Family and carer smoking control programmes for reducing children's exposure to environmental tobacco smoke

Behrooz Behbod; Mohit Sharma; Ruchi Baxi; Robert Roseby; Premila Webster

doi:10.1002/14651858.CD001746.pub4

. 2018 Jan 31;2018(1):CD001746. doi: 10.1002/14651858.CD001746.pub4

Family and carer smoking control programmes for reducing children's exposure to environmental tobacco smoke

Behrooz Behbod ^1,^2,^✉, Mohit Sharma ¹, Ruchi Baxi ¹, Robert Roseby ³, Premila Webster ¹

Editor: Cochrane Tobacco Addiction Group

PMCID: PMC6491082 PMID: 29383710

Abstract

Background

Children's exposure to other people's tobacco smoke (environmental tobacco smoke, or ETS) is associated with a range of adverse health outcomes for children. Parental smoking is a common source of children's exposure to ETS. Older children in child care or educational settings are also at risk of exposure to ETS. Preventing exposure to ETS during infancy and childhood has significant potential to improve children's health worldwide.

Objectives

To determine the effectiveness of interventions designed to reduce exposure of children to environmental tobacco smoke, or ETS.

Search methods

We searched the Cochrane Tobacco Addiction Group Specialised Register and conducted additional searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PsycINFO, Embase, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Education Resource Information Center (ERIC), and the Social Science Citation Index & Science Citation Index (Web of Knowledge). We conducted the most recent search in February 2017.

Selection criteria

We included controlled trials, with or without random allocation, that enrolled participants (parents and other family members, child care workers, and teachers) involved in the care and education of infants and young children (from birth to 12 years of age). All mechanisms for reducing children's ETS exposure were eligible, including smoking prevention, cessation, and control programmes. These include health promotion, social‐behavioural therapies, technology, education, and clinical interventions.

Data collection and analysis

Two review authors independently assessed studies and extracted data. Due to heterogeneity of methods and outcome measures, we did not pool results but instead synthesised study findings narratively.

Main results

Seventy‐eight studies met the inclusion criteria, and we assessed all evidence to be of low or very low quality based on GRADE assessment. We judged nine studies to be at low risk of bias, 35 to have unclear overall risk of bias, and 34 to have high risk of bias. Twenty‐one interventions targeted populations or community settings, 27 studies were conducted in the well‐child healthcare setting and 26 in the ill‐child healthcare setting. Two further studies conducted in paediatric clinics did not make clear whether visits were made to well‐ or ill‐children, and another included visits to both well‐ and ill‐children. Forty‐five studies were reported from North America, 22 from other high‐income countries, and 11 from low‐ or middle‐income countries. Only 26 of the 78 studies reported a beneficial intervention effect for reduction of child ETS exposure, 24 of which were statistically significant. Of these 24 studies, 13 used objective measures of children's ETS exposure. We were unable to pinpoint what made these programmes effective. Studies showing a significant effect used a range of interventions: nine used in‐person counselling or motivational interviewing; another study used telephone counselling, and one used a combination of in‐person and telephone counselling; three used multi‐component counselling‐based interventions; two used multi‐component education‐based interventions; one used a school‐based strategy; four used educational interventions, including one that used picture books; one used a smoking cessation intervention; one used a brief intervention; and another did not describe the intervention. Of the 52 studies that did not show a significant reduction in child ETS exposure, 19 used more intensive counselling approaches, including motivational interviewing, education, coaching, and smoking cessation brief advice. Other interventions consisted of brief advice or counselling (10 studies), feedback of a biological measure of children's ETS exposure (six studies), nicotine replacement therapy (two studies), feedback of maternal cotinine (one study), computerised risk assessment (one study), telephone smoking cessation support (two studies), educational home visits (eight studies), group sessions (one study), educational materials (three studies), and school‐based policy and health promotion (one study). Some studies employed more than one intervention. 35 of the 78 studies reported a reduction in ETS exposure for children, irrespective of assignment to intervention and comparison groups. One study did not aim to reduce children's tobacco smoke exposure but rather sought to reduce symptoms of asthma, and found a significant reduction in symptoms among the group exposed to motivational interviewing. We found little evidence of difference in effectiveness of interventions between the well infant, child respiratory illness, and other child illness settings as contexts for parental smoking cessation interventions.

Authors' conclusions

A minority of interventions have been shown to reduce children's exposure to environmental tobacco smoke and improve children's health, but the features that differentiate the effective interventions from those without clear evidence of effectiveness remain unclear. The evidence was judged to be of low or very low quality, as many of the trials are at a high risk of bias, are small and inadequately powered, with heterogeneous interventions and populations.

Plain language summary

Can interventions for parents and people caring for children reduce children's exposure to tobacco smoke?

Background

Children exposed to cigarette smoke (environmental tobacco smoke) are at greater risk of lung problems, infections, and serious complications including sudden infant death syndrome. Preventing exposure to cigarette smoke in infancy and childhood might significantly improve children's health worldwide. Parental smoking is a common source of cigarette exposure for children. Older children are also at risk of exposure to cigarette smoke in child care or educational settings.

Study characteristics

We searched six databases for relevant research. This is an update of a previously published review, and the date of the most recent search was February 2017. We found 78 studies on the effects of interventions aimed at family and carers with the goal of reducing children’s exposure to tobacco smoke. These studies included parents and other family members, child care workers, and teachers involved in the care and education of infants and young children (from birth to 12 years of age), and used a variety of interventions, including different kinds of counselling, brief advice, and educational materials.

Key results

Only 26 studies reported that an intervention was successful in reducing children’s exposure to tobacco smoke. These studies used a range of interventions. Nine studies used more intensive counselling methods or motivational interviewing, but in other studies, these types of interventions were not effective. Of the 52 studies that did not show a significant reduction in child tobacco smoke exposure, 19 used intensive counselling methods or motivational interviewing. One study successfully reduced children's asthma symptoms by using motivational interviewing. This review does not show whether any particular interventions reduced parental smoking and child smoke exposure more effectively than others.

Quality of evidence

The quality of evidence ranged from low to very low. Future studies should aim to provide evidence of higher quality by addressing study design problems, including more participants, and describing interventions in more detail.

Summary of findings

Background

Active smoking has been recognised as harmful to the smoker for over six decades, since the landmark Doll and Hill publication (Doll 1950), but it was not until 1974 that the medical literature first discussed parental smoking, exposure to environmental tobacco smoke (ETS), and the effects of ETS on children (Harlap 1974). Overwhelming evidence indicates that parental smoking is associated with a range of adverse health effects for children (NHMRC 1997). Perhaps its most obvious association is with increased risk, increased severity, and greater likelihood of admission to hospital of children with lower and upper respiratory tract disease (Strachan 1997; Strachan 1998, respectively). An increasing body of evidence describes an association between parental smoking and increased risk of serious bacterial infections such as meningitis among children (Iles 2001). In addition, Lam 2001 reported that ETS exposure increases health service use and costs, and Chiswell 2017 described associated poorer surgical outcomes.

Furthermore, parental smoking confers a significantly increased risk of sudden infant death syndrome (SIDS) (Golding 1997). This effect is present regardless of which parent is the smoker (Blair 1999), and it is the strongest modifiable risk factor for SIDS. In addition, research across several continents over the last two decades has found that children of smokers have an increased risk of uptake in adolescence, perhaps as a result of role modelling and/or increased access to cigarettes (Mays 2014). There is also an increased risk of respiratory symptoms persisting into adulthood among children exposed to ETS from their parents or carers, but who do not themselves take up smoking later in life (Pugmire 2014).

Parental smoking is a common but preventable source of infant and childhood morbidity. The World Health Organization (WHO) has identified the need to reduce parental smoking as a key element of action to encourage health and development in early childhood, particularly among those living in difficult social and economic circumstances (WHO 1999; WHO 2013). In some countries, strong relationships between socioeconomic status and environmental quality are evident (Moore 2012), and strategies to reduce smoking and improve child health outcomes must be underpinned by recognition of finite resources and the limited control that some individuals and families have over environmental and social situations.

Infants' and toddlers' exposure to smoking occurs primarily within the home environment, as this is where they spend most of their time. Older children may also be exposed to smoking in a variety of child care and educational settings in which they spend their time. As children increase their time spent in commercial and informal child care settings, the importance of child care workers' behaviours increases. Similarly, environments in which young children are exposed extend beyond the home and include shopping centres, meeting places, and other social environments.

Tobacco cessation strategies and interventions to reduce ETS have had mixed success, often providing small benefits on an individual level (Rosen 2014). Systematic reviews have previously demonstrated that individual counselling increases cessation rates (Lancaster 2017), and that simple advice from a physician may have a positive effect in triggering quit attempts (Stead 2013). In relation to children's exposure in utero and during the early years, smoking cessation interventions for pregnant women can be effective in reducing smoking (Coleman 2015; Chamberlain 2017). Although smoke‐free legislation in England has contributed to the 79% reduction in children’s ETS exposure since 1998 (Jarvis 2015), variability is ongoing, and children in families from lower socioeconomic status remain at greater risk of ETS exposure (Moore 2012). Globally, 80% of the world's smokers live in low‐ and middle‐income countries (WHO 2014), which have demonstrated less political will to enforce smoke‐free legislation (Pugmire 2017).

Objectives

To determine the effectiveness of interventions designed to reduce exposure of children to environmental tobacco smoke, or ETS.

Methods

Criteria for considering studies for this review

Types of studies

Controlled trials with or without random allocation.

Types of participants

People (parents and other family members, child care workers, and teachers) involved in the care and education of infants and young children (from birth to 12 years of age).

Types of interventions

We included all mechanisms for the reduction of children's ETS exposure, including smoking prevention, smoking cessation, and any other tobacco control programmes targeting the participants described above. These included health promotion, social‐behavioural therapy, technology, and educational and clinical interventions.

We included studies in which the primary aim was to reduce children's exposure to ETS (thereby preventing adverse health outcomes), but where secondary outcomes included reduction or cessation of familial/parental/carer smoking, or changes in infant and child health measures. We also included studies where the primary outcome was reduction or cessation of familial/parental/carer smoking, resulting in reduced exposure for children.

We excluded studies on uptake of smoking by minors.

We did not restrict inclusion based on who delivered the programmes. These could include researchers, general practitioners, midwives, paediatricians, community and hospital nurses, health promotion agencies, tobacco control and anti‐cancer organisations, or health departments.

Types of outcome measures

The primary outcome measures were children's exposure to tobacco smoke, child illness and health service utilisation, and the smoking behaviours of children's parents and carers. We included studies where the only outcome was parental or carer smoking status.

We used biological verification of exposure to or absorption of ETS as the 'gold standard', but we did not require this as an inclusion criterion. Where biological verification of exposure/absorption conflicted with the parental report of exposure, we regarded the biologically verified result as correct.

Outcomes for children

Exposure to ETS: biochemical measures of children's exposure to ETS based on air monitoring for levels of nicotine or other measures of ETS (including parent‐reported behaviour change, as described in the next section)
Absorption of ETS: biochemical measures of children's absorption of ETS through cotinine in urine, blood, saliva, or hair
Frequency of childhood illness events, respiratory problems (changes in lung function or symptom scores)
Use of health services: admission to hospital; frequency of use of general practitioners (GPs); frequency of medication use

Outcomes for parents and carers

Behaviour change in relation to children's exposure to ETS: We noted any reported bans or restrictions on smoking at home or in other environments or in designated smoking areas outside the home
Smoking behaviour, including cessation, reduction, or uptake, using biochemically validated measures of smoking behaviour (e.g. thiocyanates; cotinine levels in blood, urine, or saliva), or self‐report
Maternal postpartum smoking status
Costs and cost‐effectiveness associated with interventions and outcomes

We reported biochemical confirmation of parental self‐reported quit status or changes in behaviour such as moves to smoke outside, but we did not exclude studies without this measurement. Most studies did not use biochemical validation. However, there is conflicting evidence regarding the validity of self‐report of smoking status. Some trial authors suggest that self‐report is reasonably accurate in community settings (Dwyer 1986; Velicer 1992; Patrick 1994), whereas others suggest that parental self‐reports of smoke consumption and ETS are frequently underestimated (Jarvis 1987; Ford 1997; Matthews 1999). For example, in clinical situations where a clinician is the interviewer, social bias may influence the report towards the socially desired response.

Researchers and clinicians often prefer to use levels of nicotine or its breakdown products, by contrast, as a measure of real reductions in smoking or ETS. Cotinine is a metabolic breakdown product of nicotine with a half‐life of about one day (Haley 1983). Its half‐life is longer in non‐smokers such as infants and young children (Idle 1990). Smoke exposure can be detected by hair cotinine (Zahlsen 1994; Nafstad 1997; Al‐Delaimy 2002a; Al‐Delaimy 2002b), and absorption by urinary cotinine (Jarvis 1984; Bakoula 1995). Long‐term exposure is best estimated by hair cotinine, whereas urinary cotinine is more informative of short‐term exposure. Saliva cotinine approximates to blood cotinine concentrations, and collection is simple and non‐invasive.

Search methods for identification of studies

This is the fourth update of this review. Search methods for the previous searches are described in previously published versions of this review (Roseby 2002; Priest 2008; Baxi 2014).

Nia Wyn Roberts, Outreach Librarian, Bodleian Health Care Libraries, updated the search. We searched the Cochrane Central Register of Controlled Trials (Issue 2011) in the Cochrane Library, MEDLINE (OvidSP) (1948 to the present), Embase (OvidSP) (1974 to the present), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EbscoHOST) (1980 to the present), PsycINFO (OvidSP) (1967 to the present), and the Education Resource Information Center (ERIC) (ProQuest) (1966 to the present). In June 2011, we conducted a search for articles from 2007 to 2011. The Trial Search Co‐ordinator searched the CochraneTobacco Addiction Group Specialised Register. We conducted the most recent search in February 2017.

We obtained and reviewed reports of all references identified as possibly describing randomised controlled trials (RCTs) or controlled trials (CTs), and we checked the reference lists of all identified RCTs and CTs to identify potentially relevant citations. We made enquiries regarding other known published and unpublished studies so that we could include these results in our review.

We have presented search strategies for the key databases in Appendix 1 (MEDLINE); Appendix 2 (Embase); Appendix 3 (CINAHL); Appendix 4 (PsycINFO); Appendix 5 (ERIC); and Appendix 6 (the Cochrane Library).

Data collection and analysis

Two review authors (BB and MS) independently screened studies for inclusion using Covidence. Three review authors independently undertook assessment of quality and extraction of included study details and results. For this update, BB reviewed all studies; and MS, RB, and RR each reviewed one‐third of the studies and compared results. We created a data extraction spreadsheet in Microsoft Excel.

We extracted information on methods, participants, intervention and control conditions, and outcomes. We were particularly interested in aspects of intervention development that may have contributed to a stronger, more appropriate or sustained intervention. We extracted information on the theory underlying the intervention development and content, process indicators and descriptions of community consultation and/or participation in the planning and implementation of the intervention, incentives (if present), and concerns regarding intervention programmes. We also recorded any information about costs, either in terms of evaluations of cost‐effectiveness, or simply where costs were mentioned. Where possible, we examined outcomes by gender, age, and socioeconomic status.

We resolved differences between reviewers' screening and extraction results by discussion or by consultation with a third review author. Given the heterogeneity of study design and characteristics, we considered a quantitative estimate of effect to be inappropriate and therefore provided a narrative synthesis.

Assessment of risk of bias in included studies

Two review authors independently assessed risk of bias for all included studies, including those included in previous versions of this review. We categorised risk of bias as high, low, or unclear for randomisation, allocation concealment, incomplete data, blinding of outcome assessment, and other bias, in accordance with methods described in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). We resolved differences by discussion.

Sequence generation (checking for possible selection bias)

We have described the methods used to generate the allocation sequence and have assessed these methods as having:

low risk of bias (any truly random process, e.g. random number table, computer random number generator);
high risk of bias (any non‐random process, e.g. odd or even date of birth, hospital or clinic record number); or
unclear risk of bias (insufficient information provided with which to judge).

Allocation concealment (checking for possible selection bias)

We have described the methods used to conceal the allocation sequence in sufficient detail to determine whether intervention allocation could have been foreseen in advance of, or during, recruitment, or changed after assignment. We have assessed these methods as having:

low risk of bias (e.g. telephone or central randomisation; consecutively numbered sealed opaque envelopes);
high risk of bias (open allocation; unsealed or non‐opaque envelopes; alternation; date of birth); or
unclear risk of bias (insufficient information provided with which to judge).

Blinding (checking for possible detection bias)

We have described the methods reported, if any, to blind study participants and personnel from knowledge of which intervention a participant received. With educational interventions (such as those assessed in this review) it is often not possible to blind participants to group allocation, and hence we did not evaluate blinding based on performance bias but rather based solely on the potential to introduce detection bias. It is possible for outcome assessors to be blinded to group allocation and we have noted where there was partial blinding. We have assessed study methods as having high risk of bias, low risk of bias, or unclear risk.

When investigators objectively measured findings (e.g. biochemical validation, household air nicotine monitors), we assessed blinding as adequate to prevent detection bias.

Incomplete outcome data (checking for possible attrition bias through withdrawals, dropouts, or protocol deviations)

Within each included study, we have described for each outcome or class of outcomes the completeness of data, including attrition and exclusions from analysis. We have noted whether attrition and exclusions were reported, the numbers included in the analysis at each stage (compared with the total number of randomised participants), reasons for attrition or exclusion where reported, and whether missing data were balanced across groups.

Other bias (e.g. selective reporting bias)

We have noted any other potential sources of bias that were not related to the four sources discussed above.

Overall risk of bias

We made explicit judgements about whether studies were at high, moderate, or low risk of bias, according to the criteria given in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). With reference to the specific types of bias discussed above, we assessed the likely magnitude and direction of bias, and whether we considered it likely to impact study findings.

Results

Description of studies

We included 78 studies in this review, 21 of which were identified in the most recent update; see the search study flow diagram in Figure 1 (Abdullah 2015; Blaakman 2015; Borrelli 2016; Chen 2016; Collins 2015; Cooper 2014; Daly 2016; Eakin 2014; Hafkamp‐de 2014; Harutyunyan 2013; Joseph 2014; Kegler 2015; Nicholson 2015; Ortega 2015; Pollak 2015; Schuck 2014; Streja 2014; Ulbricht 2014; Walker 2015; Wang 2015; Yucel 2014). We have summarised the characteristics of included studies below, and have provided further detail in the Characteristics of included studies table.

We identified five additional studies for which outcome data are not yet available; we identified three of these in the previous update (Johnston 2010; Rosen 2011; Wagener 2012; Hutchinson 2013; Risica 2016). We have provided information about these ongoing studies in the Characteristics of ongoing studies table.

We have listed 35 studies as excluded. The most common reasons for exclusion were study design; participants not meeting inclusion criteria; outcomes not related to environmental tobacco smoke exposure; and lack of outcome data. Further information is available in the Characteristics of excluded studies table.

Intervention setting

One study evaluated outcomes for smoking mothers who called a telephone smoking cessation assistance counselling service (Davis 1992), and another recruited participants from callers to a 2‐1‐1 service (Kegler 2015). Seven studies introduced interventions in a school setting (Zhang 1993; Elder 1996; Ekerbicer 2007; Halterman 2011; Schuck 2014; Wang 2015; Chen 2016). Five further studies introduced interventions in other community settings (Conway 2004; Herbert 2011; Prokhorov 2013; Eakin 2014; Ulbricht 2014; see Characteristics of included studies for futher details).

Eight studies recruited from general healthcare settings (Harutyunyan 2013; Streja 2014; Yucel 2014; Abdullah 2015; Blaakman 2015; Collins 2015; Pollak 2015; Walker 2015; see Characteristics of included studies for futher details). Twenty‐five studies took place in well‐child healthcare settings, and recruited participants postnatally, at well‐child health visits or at infant immunisation clinics. Fourteen of these studies were peripartum, recruiting participants via maternity hospitals, from their records, or through midwives and general practitioners (Woodward 1987; Greenberg 1994; Severson 1997; Armstrong 2000; Van't Hof 2000; Emmons 2001; Ratner 2001; Pulley 2002; Schonberger 2005; Wiggins 2005; Culp 2007; French 2007; Hannover 2009; Cooper 2014). Chilmonczyk 1992, Vineis 1993, Eriksen 1996, Fossum 2004, Zakarian 2004, Abdullah 2005, Kallio 2006, Winickoff 2010, Baheiraei 2011, Hafkamp‐de 2014, Joseph 2014, and Daly 2016 used well‐child health check visits to a doctor or maternal child health nurse. Chellini 2013 recruited from hospital and public health facility waiting rooms, as well as from supermarkets.

Twenty‐six studies reported interventions conducted in an ill‐child healthcare setting. Fourteen of these identified families through their children's respiratory problems (Hughes 1991; McIntosh 1994; Wahlgren 1997; Irvine 1999; Wilson 2001; Hovell 2002; Krieger 2005; Ralston 2008; Borrelli 2010; Butz 2011; Halterman 2011 (recruited from school rather than healthcare setting); Wilson 2011; Stotts 2012; Borrelli 2016). Investigators conducted 10 studies in non‐respiratory ill‐child healthcare settings (Groner 2000; Hovell 2000; Wakefield 2002; Kimata 2004; Chan 2005; Chan 2006a; Hovell 2009; Phillips 2012; Tyc 2013; Nicholson 2015). Patel 2012 and Ralston 2013 targeted children presenting to the emergency department, approximately 40% of whom had a respiratory presenting complaint. Hovell 2000 and Hovell 2009 recruited mothers from a Special Supplemental Nutrition Program for Women, Infants, and Children, and looked at the effectiveness of counselling on smoking rates and children's ETS exposure among women of low income, high risk, and ethnically diverse backgrounds.

Two additional studies conducted in paediatric clinics did not specify whether they were conducted in the context of well‐child or ill‐child health visits (Curry 2003; Nuesslein 2006), and Yilmaz 2006 recruited children visiting paediatric clinics for treatment of primary conditions or for a well‐child visit.

Main target of intervention

Children's ETS exposure can be reduced by encouraging avoidance of children's exposure to cigarettes smoked, for example, by moving the child or the smoker to a different location, reducing the number of cigarettes smoked by the parent or carer, or having the smoker cease smoking altogether. The aims of studies identified by this review were heterogeneous. Here, we consider only smoking and ETS targets; we do not describe other intervention components, such as healthy eating (e.g. Elder 1996), asthma management (e.g. Hughes 1991), or household safety (e.g. Culp 2007).

Of the 78 included studies, 18 aimed solely for parental or carer smoking cessation or reduction (Vineis 1993; Zhang 1993; Severson 1997; Groner 2000; Emmons 2001; Wakefield 2002; Curry 2003; Kimata 2004; Chan 2005; Wiggins 2005; Kallio 2006; Nuesslein 2006; Ralston 2008; Borrelli 2010; Ralston 2013; Cooper 2014; Pollak 2015; Borrelli 2016). Twenty‐five studies aimed solely for reducing children's exposure to cigarettes smoked (Chilmonczyk 1992; Davis 1992; Elder 1996; Wahlgren 1997; Hovell 2000; Wilson 2001; Pulley 2002; Baheiraei 2011; Butz 2011; Herbert 2011; Wilson 2011; Stotts 2012; Chellini 2013; Prokhorov 2013; Tyc 2013; Harutyunyan 2013; Hafkamp‐de 2014; Schuck 2014; Streja 2014; Ulbricht 2014; Collins 2015; Kegler 2015; Nicholson 2015; Ortega 2015; Chen 2016), while 30 studies aimed for a combination of parental or carer cessation, reduction, or avoidance (Woodward 1987; Hughes 1991; Greenberg 1994; McIntosh 1994; Eriksen 1996; Irvine 1999; Armstrong 2000; Hovell 2000; Conway 2004; Fossum 2004; Zakarian 2004; Abdullah 2005; Krieger 2005; Schonberger 2005; Chan 2006a; Yilmaz 2006; Culp 2007; Ekerbicer 2007; Hovell 2009; Winickoff 2010; Halterman 2011; Patel 2012; Eakin 2014; Joseph 2014; Yucel 2014; Abdullah 2015; Blaakman 2015; Walker 2015; Wang 2015; Daly 2016). Five studies aimed to prevent reuptake of smoking postpartum (Van't Hof 2000; Ratner 2001; French 2007; Hannover 2009; Phillips 2012).

All studies aimed to achieve changes in behaviour in some way to reduce child ETS exposure. Eleven studies did not expressly include an educational or knowledge‐building component in their interventions but instead targeted change in attitudes and behaviours (Chilmonczyk 1992; Zhang 1993; Wahlgren 1997; Hovell 2000; Curry 2003; Zakarian 2004; Chan 2005; Nuesslein 2006; Cooper 2014; Abdullah 2015; Ortega 2015).

Location of studies

Most studies were reported from high‐income countries. Forty‐five studies were from North America, with 42 from the USA and three from Canada. Four studies were from Australia, and one was conducted in both Australia and New Zealand (Walker 2015). Three studies were from each of the UK, Germany, and the Netherlands. Two studies were from Italy (Vineis 1993; Chellini 2013). One study was reported from each of Finland (Kallio 2006), Japan (Kimata 2004), Sweden (Fossum 2004), Norway (Eriksen 1996), Taiwan (Chen 2016), and Spain (Ortega 2015). Fifteen of the studies conducted in high‐income countries specifically targeted disadvantaged, low‐income, and/or culturally diverse populations. Eleven studies were reported from low‐ or middle‐income countries, with six from China (Zhang 1993; Abdullah 2005; Chan 2005; Chan 2006a; Abdullah 2015; Wang 2015), three from Turkey (Yilmaz 2006; Ekerbicer 2007; Yucel 2014), and one from each of Iran (Baheiraei 2011) and Armenia (Harutyunyan 2013).

Participants

Twenty‐four studies targeted mothers only. Hovell 2009, Yucel 2014, and Pollak 2015 targeted mothers but invited partners or other family members to participate in counselling. One study targeted fathers by educating their non‐smoking wives (Chan 2006a). Thirty‐six studies targeted both parents. Zhang 1993 targeted fathers only; Borrelli 2010, Wilson 2011, Patel 2012, and Ralston 2013 targeted carers; Elder 1996 targeted teachers only; Wahlgren 1997, Butz 2011, and Stotts 2012 targeted families; and Krieger 2005, Halterman 2011, Harutyunyan 2013, Prokhorov 2013, and Kegler 2015 targeted households.

Age group

We stratified studies according to age groups of children: infants (younger than one year); preschoolers (up to age six); and school age (six to twelve years). Twenty‐three studies examined measures to reduce ETS exclusively for infants. Nineteen studies examined measures to reduce ETS for children up to and including preschool age, and 18 studies considered measures for children up to and including school age. One study followed pregnant women between 13 and 29 weeks' gestation for 12 months (Pollak 2015). Eight studies examined interventions to reduce ETS that included older age groups: Wahlgren 1997 included parents of children aged 6 to 17 years; Hovell 2002 and Borrelli 2016 included parents of children aged 3 to 17 years; Chan 2006a included parents of children from birth to 15 years; Yilmaz 2006 included mothers of children younger than 16 years of age; Streja 2014 included parents or guardians of children from 2 to 14 years of age; and Borrelli 2010, Chellini 2013, Prokhorov 2013, Tyc 2013,Kegler 2015, and Nicholson 2015 included children younger than 18 years of age. Five studies did not provide children's ages (Curry 2003; Chan 2005; Nuesslein 2006; Ralston 2008; Ralston 2013).

Theoretical framework

Forty‐five of the 78 studies expressly employed a theoretical framework in the design and/or development of the intervention. Fifteen studies used motivational interviewing (Emmons 2001; Curry 2003; Chan 2005; French 2007; Hannover 2009; Borrelli 2010; Baheiraei 2011; Halterman 2011; Phillips 2012; Stotts 2012; Ralston 2013; Eakin 2014; Blaakman 2015; Kegler 2015; Borrelli 2016). Seven used a social learning model (Greenberg 1994; Elder 1996; Conway 2004; Fossum 2004; Harutyunyan 2013; Ulbricht 2014; Blaakman 2015), and six used the stages of change component of Prochaska's transtheoretical model (Abdullah 2005; Krieger 2005; Ralston 2008; Winickoff 2010; Patel 2012; Ralston 2013). Chen 2016 combined transtheoretical and I‐change models, and Winickoff 2010 combined the transtheoretical stages of change model with social learning theory, the health beliefs model, cognitive‐behavioural theory, Wagner's chronic care model, and behavioural and systems theory. Several studies combined motivational interviewing with other frameworks, including stages of change (Ralston 2013; Wang 2015), Maori and Aboriginal holistic models of health (Walker 2015), the teachable moment (Borrelli 2016), cognitive‐behavioural therapy (Joseph 2014), cognitive‐behavioural skill building (Schuck 2014), and social cognitive theory. Kegler 2015 combined motivational interviewing with both the transtheoretical stages of change model and social cognitive theory, while Pollak 2015 combined motivational interviewing with both the teachable moment model and cognitive‐behavioural couples therapy.

McIntosh 1994 developed activities for the parent manual based on behaviour modification theory. Wahlgren 1997 tailored the programme to individual families and incorporated several behavioural modification techniques, including stimulus control, shaping, personal feedback, and contingency contracting. Groner 2000 employed the health belief model, and Wakefield 2002 used a harm minimisation approach that was based on previous research indicating that restrictions produced significantly lower urinary cotinine levels. Ratner 2001 utilised Marlatt's relapse model. Chan 2006a used Fishbein's theory of reasoned action and Ajzen's theory of planned behaviour in developing its educational intervention. Hovell 2009 used the behavioural ecological model in developing the counselling intervention. Herbert 2011 used a family‐centred assessment and intervention model to empower families to reduce cigarettes smoked in the home. Tyc 2013 and Nicholson 2015 used behavioural contracting, problem solving, and social reinforcement. Ortega 2015 used the 5 As (Ask, Advise, Assess, Assist, and Arrange) approach, and Streja 2014 employed the Health Behaviour Framework (previously the Adherence Model).

Acceptability of intervention to participants

Six studies appear to have involved consultation with potential participants as part of the development of the intervention (Hughes 1991; Davis 1992; Hovell 2000; Borrelli 2010; Streja 2014; Chen 2016). Davis 1992 employed focus groups with smokers and non‐smokers to understand their beliefs and attitudes towards smoking and cessation in order to develop improved self‐help materials. Borrelli 2010 conducted focus groups to better understand Latino culture and to modify the motivational interviewing technique accordingly.

Process indicators

Process indicators provide important information regarding the integrity of the way in which interventions were implemented. However, only 32 of the 78 studies described process indicators well (Hughes 1991; Chilmonczyk 1992; Davis 1992; Greenberg 1994; McIntosh 1994; Eriksen 1996; Severson 1997; Hovell 2000; Emmons 2001; Hovell 2002; Wakefield 2002; Fossum 2004; Zakarian 2004; Abdullah 2005; Wiggins 2005; Culp 2007; Hannover 2009; Hovell 2009; Borrelli 2010; Winickoff 2010; Stotts 2012; Tyc 2013; Cooper 2014; Eakin 2014; Hafkamp‐de 2014; Joseph 2014; Schuck 2014; Abdullah 2015; Blaakman 2015; Kegler 2015; Borrelli 2016; Daly 2016). More specifically, 11 studies reported that they maintained regular monitoring and support with those responsible for providing the intervention (Hughes 1991; Greenberg 1994; Emmons 2001; Culp 2007; Hannover 2009; Hovell 2009; Borrelli 2010; Eakin 2014; Hafkamp‐de 2014; Abdullah 2015; Daly 2016), and 19 reported that they evaluated the extent to which participants received, read, undertook, or adhered to the intervention as intended (Davis 1992; McIntosh 1994; Severson 1997; Hovell 2002; Wakefield 2002; Zakarian 2004; Abdullah 2005; Wiggins 2005; Culp 2007; Hovell 2009; Winickoff 2010; Stotts 2012; Cooper 2014; Joseph 2014; Schuck 2014; Abdullah 2015; Blaakman 2015; Kegler 2015; Borrelli 2016). Among those that commented on the monitoring of study implementation, one study recommended prompting providers over the course of the study to ensure appropriate implementation (Severson 1997). Another study reported the collection of qualitative data showing the opinions of nurses delivering the intervention (Fossum 2004).

Biological verification of children's exposure and absorption

Thirty studies used biological evidence of children's ETS absorption by measuring cotinine in urine or saliva, and 14 studies used environmental monitors of children's exposure to ETS. Eight of the 14 used passive sampling nicotine monitors as a primary study outcome. One study also measured particulate matter in the child's bedroom and living room (Butz 2011). The remaining studies used air nicotine monitors to promote or verify the accuracy of parent reporting of smoking behaviours. Wahlgren 1997 reported using air nicotine monitors in a room where greatest exposure to ETS was reported for two weeks before clinic visits to verify parent reports of cigarette consumption. Hovell 2000, Hovell 2002, Zakarian 2004, and Hovell 2009 used inactive air nicotine monitors placed in three rooms where children’s greatest ETS exposure was reported, to promote accurate self‐reporting of smoking behaviours by mothers. These studies also placed active air monitors for a selected proportion of the total sample: Hovell 2000 in a randomly selected half of the sample; both Hovell 2002 and Zakarian 2004 in 20% of the sample; and Hovell 2009 in a randomly selected 24% of the sample at six months. Zakarian 2004 reported randomly selecting these homes and placing monitors in the homes one week before data collection, while Hovell 2002 did not report how the 20% of homes were selected but reported that they were used only for baseline and post‐test measures. Cost was given as a reason for not using active air nicotine monitors across the whole sample. Eakin 2014 placed two monitors for seven days in the room where the child slept and in another room identified as a major activity room by the carer. Streja 2014 placed two monitors, each for one of two consecutive seven‐day periods in a major activity room. Kegler 2015 used passive air monitors after the three‐month visit for all participants reporting full or no bans, and for half of the participants reporting partial bans. However, investigators did not specify the location of the monitors. Borrelli 2016 placed two monitors for seven days at baseline and after call 5, they placed one in the room where the child spent the most time, and the child wore one.

Eleven interventions used feedback to parents of biological evidence of children's ETS absorption as a stimulus for parental behaviour change (Chilmonczyk 1992; McIntosh 1994; Wilson 2001; Wakefield 2002; Ekerbicer 2007; Wilson 2011; Harutyunyan 2013; Ulbricht 2014; Yucel 2014; Wang 2015; Daly 2016). Twenty‐three studies used biological validation of parental smoking cessation by measuring cotinine in urine, saliva, or serum (Woodward 1987; Irvine 1999; Hovell 2000; Hovell 2002; Fossum 2004; Zakarian 2004; Abdullah 2005; Kallio 2006; Nuesslein 2006; French 2007; Hovell 2009; Winickoff 2010; Phillips 2012; Tyc 2013; Cooper 2014), and/or expired carbon monoxide (Emmons 2001; Ratner 2001; Curry 2003; Abdullah 2005; Schonberger 2005; Borrelli 2010; Stotts 2012; Cooper 2014).

Length of follow‐up

For this review we determined length of follow‐up as extending from completion of the intervention to time of data collection. Length of follow‐up is important to determine, as it affects the extent to which sustainability and long‐term outcomes can be assessed. While short‐term reductions in children's ETS exposure have provided some benefit for children's health outcomes, the ultimate goal is long‐term and sustained change in order to maximise the positive impact on children's health and well‐being as they grow and develop. Twenty‐eight studies included in this review reported follow‐up of at least 12 months from the end of the intervention. Another 24 studies reported shorter follow‐up periods of between 6 and 12 months. Wahlgren 1997 debriefed participants at the six‐month follow‐up and reported ongoing follow‐up 8 and 18 months after that. Long‐term effectiveness was particularly difficult to assess in the remaining studies, specifically those with follow‐up periods of six months or less. McIntosh 1994 reported follow‐up periods that ranged between four and six months. Stotts 2012 reported a follow‐up period of six months from baseline, but it was unclear what the follow‐up was post intervention. The remaining studies (24) used a follow‐up time of less than six months.

Sample size

Thirty‐nine of the 78 studies mention conducting a power calculation in the design of their studies (Woodward 1987; Greenberg 1994; McIntosh 1994; Severson 1997; Wahlgren 1997; Irvine 1999; Armstrong 2000; Groner 2000; Hovell 2000; Emmons 2001; Wakefield 2002; Conway 2004; Krieger 2005; Schonberger 2005; Wiggins 2005; French 2007; Ralston 2008; Hannover 2009; Hovell 2009; Borrelli 2010; Baheiraei 2011; Butz 2011; Halterman 2011; Wilson 2011; Phillips 2012; Chellini 2013; Harutyunyan 2013; Prokhorov 2013; Ralston 2013; Cooper 2014; Ulbricht 2014; Abdullah 2015; Ortega 2015; Pollak 2015; Walker 2015; Wang 2015; Borrelli 2016; Chen 2016; Daly 2016). Of these, McIntosh 1994, Wahlgren 1997, Borrelli 2010, Harutyunyan 2013, Cooper 2014, Pollak 2015, and Daly 2016 explicitly mention that the statistical power of their study was limited by the small sample size. Although Streja 2014 did not present a power calculation, the authors did include a lack of statistical power as one of their limitations.

Risk of bias in included studies

To meet inclusion criteria for this review, studies had to be controlled trials. For this update, we assessed risk of bias for all of the included studies. We have summarised this assessment in Figure 2 and Figure 3.

Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

Allocation

Investigators rarely described the method of randomisation in sufficient detail to permit assessment of whether allocation was concealed at the time of trial entry. For example, it was common for studies to merely state that participants were randomised. Quasi‐randomisation was not uncommon even in large trials. Twelve and 32 studies, respectively, were at high and unclear risk of bias from poor randomisation and lack of randomisation. Ten and 43 studies, respectively, were at high and unclear risk of bias from allocation concealment, with many studies not describing allocation concealment.

Blinding (detection bias)

Very few trials had any blinding of participants or providers, largely due to pragmatic issues associated with administering an educational intervention. We have noted in the Characteristics of included studies tables where there was blinding of outcome assessors. We classified those trials without adequate blinding of outcome assessors or that used a subjective measure of outcome assessment as having high risk of bias. Nine and 10 studies, respectively, were at high and unclear risk of bias from blinding of outcome assessment.

Incomplete outcome data

Attrition from withdrawals and exclusions from trials were common, and often studies did not clearly specify the reasons for this. Attrition presents a potentially serious risk of bias in these studies. We have provided in the Characteristics of included studies table levels of attrition for each study, and information about any intention‐to‐treat analyses performed. Eighteen and six studies, respectively, were at high and unclear risk of bias due to incomplete outcome data.

Other potential sources of bias

We judged 22 studies to be at high risk of "other potential sources of bias". In 12 of these studies, this related to systematic differences in the characteristics of treatment groups (Pulley 2002; Culp 2007; French 2007; Ralston 2008; Hovell 2009; Butz 2011; Phillips 2012; Prokhorov 2013; Hafkamp‐de 2014; Abdullah 2015; Ortega 2015; Borrelli 2016). In four studies, this was due to potential exposure misclassification (Eakin 2014; Hafkamp‐de 2014; Joseph 2014; Daly 2016); in four this was due to a lack of intention‐to‐treat analysis (Pulley 2002; Hannover 2009; Patel 2012; Prokhorov 2013); in three this was due to the possibility of contamination between groups (Chan 2006a; Hafkamp‐de 2014; Abdullah 2015); in one it was due to a Hawthorne effect (Ortega 2015); and in another to the possibility of social desirability bias resulting from the interview format (Abdullah 2015).

Effects of interventions

See: Table 1; Table 2; Table 3

Summary of findings for the main comparison. Summary of findings: community‐based interventions for reducing children's exposure to environmental tobacco smoke.

Community‐based interventions for reducing children's exposure to environmental tobacco smoke (ETS)
Patient or population: people who smoke and are involved in the care of young children (birth to 12 years of age) Settings: community Intervention: behavioural interventions Comparison: usual care or minimal intervention
Intervention type and outcomes¹	Impact	No. of participants²  (studies)	Quality of the evidence  (GRADE)	Comments
Multi‐component, counselling‐based interventions assessed with biochemical validation of ETS exposure and self‐report length of follow‐up: 3 to 12 months	Of 7 studies in this group, 3 found that the intervention group was significantly more likely than the control group to implement full home smoking bans. One study found that the geometric mean hair nicotine level in the intervention group significantly decreased from 0.30 ng/mg to 0.23 ng/mg (P = 0.024), but not in the control group. Four studies found no significant differences in the change in cotinine levels between intervention and control groups.	2880  (7 studies)	+‐‐‐ VERY LOW³
Multi‐comoponent, education‐based interventions assessed with biochemical validation of ETS exposure length of follow‐up: 6 months	One study, with similar children’s urinary cotinine levels at baseline, found that cotinine levels were significantly lower (Z = ‐3.136; P = 0.002) in the intervention group (1.29 ng/mL) than in the control group (1.78 ng/mL) at 6 month follow‐up. The other study found no significant differences between intervention and control groups in child urine cotinine levels.	307  (2 studies)	+‐‐‐ VERY LOW⁴
In‐person counselling (no additional components) assessed with biochemical validation of ETS exposure and self‐report length of follow‐up: 1 to 12 months	Of the 6 studies in this group, 3 found significantly greater reductions in cotinine levels in the intervention compared with the control group. Two studies found that the intervention group was significantly more likely to implement home smoking bans. Two studies found no significant intervention impacts.	1001  (6 studies)	+‐‐‐ VERY LOW⁵
Telephone counselling assessed with biochemical validation of ETS exposure length of follow‐up: 9 months	One study found no significant difference in the proportion of children with low urinary cotinine levels (< 10 ng/mL) amongst parents receiving telephone counselling or a note regarding their child’s cotinine result.	347  (1 study)	++‐‐ LOW⁶
ETS: environmental tobacco smoke  GRADE Working Group grades of evidence  High quality: Further research is very unlikely to change our confidence in the estimate of effect.  Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.  Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.  Very low quality: We are very uncertain about the estimate.

Interventions in the ill‐child setting for reducing children's exposure to environmental tobacco smoke (ETS)
Patient or population: people who smoke and are involved in the care of young children (birth to 12 years of age) Settings: healthcare ‐ ill‐child setting Intervention: behavioural interventions Comparison: usual care or minimal intervention
Intervention type and outcomes¹	Impact	No. of participants²  (studies)	Quality of the evidence  (GRADE)	Comments
Multi‐component, counselling‐based interventions assessed with biochemical validation of ETS exposure and self‐report length of follow‐up: 5 to 12 months	Three studies found no significant differences between intervention and control groups.	746 (3 studies)	+‐‐‐ VERY LOW³
Multi‐component, education‐based interventions assessed with biochemical validation of ETS exposure and self‐report length of follow‐up: 6 to 13 months	One study reported significantly lower child's ETS exposure at home by any smoker at 12 months' follow‐up (52% vs 58%; P = 0.03). Six studies found no significant differences between intervention and control groups.	2936 (7 studies)	+‐‐‐ VERY LOW⁴
In‐person counselling (no additional components) assessed with biochemical validation of ETS exposure, self‐report length of follow‐up: 3 to 18 months	Eight studies appeared to show intervention benefits based on self‐reported ETS exposures but no significant differences between intervention and control groups in objective measures of exposure (e.g. cotinine).	1835 (8 studies)	+‐‐‐ VERY LOW⁵
Telephone counselling	No studies examined telephone counselling delivered in the ill‐child setting and measured ETS exposure.
Brief interventions Assessed with presence of home and car smoking ban length of follow‐up: 24 weeks	One study showed no significant differences between intervention and control groups in changed smoking policy: OR 2.0 (95% CI 0.166 to 24.069).	100 (1 study)	+‐‐‐ VERY LOW⁶
GRADE Working Group grades of evidence  High quality: Further research is very unlikely to change our confidence in the estimate of effect.  Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.  Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.  Very low quality: We are very uncertain about the estimate.

Interventions in the well‐child setting for reducing children's exposure to environmental tobacco smoke (ETS)
Patient or population: people who smoke and are involved in the care of young children (birth to 12 years of age) Settings: health care ‐ well‐child setting Intervention: behavioural interventions Comparison: usual care or minimal intervention
Intervention type and outcomes¹	Impact	No. of participants²  (studies)	Quality of the evidence  (GRADE)	Comments
Multi‐component, counselling‐based interventions assessed with biochemical validation of ETS exposure, self‐report length of follow‐up: 2 to 12 months	One study found significant reduction in ETS exposure at home in the intervention group at age 6 years, but only on per‐protocol analysis (OR 0.71, 95% CI 0.59 to 0.87). One study found an increase in smoking bans in the home (19.3%) and in the car (7%) after 8 weeks' follow‐up in the intervention group, but not in the comparison group (2.5% increase in home ban and 0% change in car ban). One study found no significant difference between intervention and control groups in children’s urinary cotinine levels.	8005 (3 studies)	+‐‐‐ VERY LOW³
Multi‐component, education‐based interventions assessed with biochemical validation of ETS exposure, self‐report length of follow‐up: 2 to 12 months	One study found that maternal self‐reported smoking at home around the infant was significantly less in the intervention group (8.6%) than in the control group (23.8%) (P < 0.05). Three studies found no evidence of effect of the intervention.	1401 (4 studies)	++‐‐ LOW⁴
In‐person counselling (no additional components) assessed with biochemical validation of ETS exposure, self‐report length of follow‐up: 3 to 90 months	One study found significantly greater reductions in geometric mean urinary cotinine in the intervention group (decrease from 48.72 ng/mg to 28.68 ng/mg) compared to the control group (decrease from 40.43 to 36.32 ng/mg). In addition, the intervention group had a significantly greater increase in the proportion of households with smoking bans at home (15% to 33.3%) compared to the control group (11.5% to 19.5%). One study found a significantly beneficial reduction in kitchen and TV room air nicotine levels in the intervention group than in the control group (P < 0.05). One study found no difference in serum cotinine concentrations between the intervention and control groups.	1483 (3 studies)	++‐‐ LOW⁵
Telephone counselling assessed with self‐report length of follow‐up: 6 months	One study found a greater proportion with partial home smoking bans in the intervention group (62.7%) than in the control group (56.4%), as well as a higher biochemically validated quit rate for the intervention group (10.6%) than for the control group (4.5%) at 6 months.	952 (1 study)	++‐‐ LOW⁶
Brief interventions assessed with self‐report length of follow‐up: not specified	One study found no significant difference in home (OR 1.04, 95 CI 0.47 to 2.28) or car smoking bans (OR 1.47, 95 CI 0.69 to 3.11) between intervention and control groups.	218 (1 study)	+‐‐‐ VERY LOW⁷
CI: confidence interval; OR: odds ratio  GRADE Working Group grades of evidence  High quality: Further research is very unlikely to change our confidence in the estimate of effect.  Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.  Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.  Very low quality: We are very uncertain about the estimate.

Date	Event	Description
1 January 2018	New search has been performed	Review update: Added 21 new studies, date of last search February 2017
1 January 2018	New citation required but conclusions have not changed	Review update with changes to review authors

Date	Event	Description
26 March 2014	Amended	Changed date for 'Assessed as up‐to‐date'
26 March 2014	Amended	Changed contact to Ruchi Baxi
18 December 2013	New citation required but conclusions have not changed	Added review authors
18 December 2013	New search has been performed	Updated review; added 21 studies; date of last search September 2013
22 June 2011	Amended	Converted additional table to appendix to correct pdf format
8 August 2008	New search has been performed	Updated review
3 July 2008	New citation required but conclusions have not changed	Added review authors

Searched February 2017
1	exp Smoking/
2	Tobacco Smoke Pollution/
3	1 or 2
4	Smoking Cessation/
5	Environmental Medicine/
6	exp Environmental Pollution/
7	Public Health/
8	Health Education/
9	Health Promotion/
10	Psychotherapy/
11	4 or 5 or 6 or 7 or 8 or 9 or 10
12	exp Family/
13	Child Day Care Centers/ or Child Care/
14	Schools, Nursery/
15	(child* or carer* or caregiver* or parent* or brother* or sister* or sibling* or nanny or nannies).ti,ab.
16	12 or 13 or 14 or 15
17	3 and 11 and 16
18	limit 17 to ("newborn infant (birth to 1 month)" or "infant (1 to 23 months)" or "preschool child (2 to 5 years)" or "child (6 to 12 years)")
19randomisedd controlled trial.pt.
20	controlled clinical trial.pt.
21	randomized.ab.
22	placebo.ab.
23	drug therapy.fs.
24	randomly.ab.
25	trial.ab.
26	groups.ab.
27	19 or 20 or 21 or 22 or 23 or 24 or 25 or 26
28	Research Design/
29	Follow‐Up Studies/
30	exp evaluation studies/
31	Prospective Studies/
32	Retrospective Studies/
33	Comparative Study/
34	Cross‐Sectional Studies/
35	27 or 28 or 29 or 30 or 31 or 32 or 33 or 34
36	18 and 35
37	limit 36 to yr="2007 ‐Current"
38	(2011* or 2012*).yr,dp,ed.
39	37 and 38

Searched February 2017
1	*smoking/
2	*smoking cessation/
3	*environmental health/
4	*pollution/
5	*public health/
6	*health education/
7	*psychotherapy/
8	2 or 3 or 4 or 5 or 6 or 7
9	*family/
10	*schools/
11	*school/
12	*nursery/
13	*nurseries/
14	*day care/
15	*child care/
16	*house/
17	*home/
18	(carer* or caregiver* or parent* or famil* or brother* or sister* or sibling* or nanny or nannies).ti,ab.
19	9 or 10 or 11 or 12 or 13 or 14 or 15 or 16 or 17 or 18
20	child/
21	newborn/
22	20 or 21
23	1 and 8 and 19 and 22
24randomisedd controlled trial/
25randomisationn/
26	controlled study/
27	evidence based medicine/
28	clinical trial/
29	(clin* adj5 trial?).ti,ab.
30	((singl* or doubl* or trebl* or tripl) adj5 (blind or mask*)).ti,ab.
31	placebos/
32	placebo*.ti,ab.
33	methodology/
34	comparative study/
35	"evaluation and follow up"/
36	prospective study/
37	(control* or prospective* or volunteer?).ti,ab.
38	24 or 25 or 26 or 27 or 28 or 29 or 30 or 31 or 32 or 33 or 34 or 35 or 36 or 37
39	23 and 38
40	limit 39 to yr="2007 ‐Current"
41	(2011* or 2012*).yr,dp,em.
42	40 and 41

Searched February 2017
S31	S15 and S29 Limiters ‐ Published Date from: 20110101‐20121231; Age Groups: Infant, Newborn: birth‐1 month, Infant: 1‐23 months, Child, Preschool: 2‐5 years, Child: 6‐12 years
S30	S15 and S29 Limiters ‐ Published Date from: 20070101‐20111231; Age Groups: Infant, Newborn: birth‐1 month, Infant: 1‐23 months, Child, Preschool: 2‐5 years, Child: 6‐12 years
S29	S16 or S17 or S18 or S19 or S20 or S21 or S22 or S23 or S24 or S25 or S26 or S27 or S28
28	TI ( control* pr prospectiv* or volunteer* ) or AB ( control* or prospectiv* or volunteer* )
S27	(MH "Evaluation Research")
S26	(MH "Comparative Studies")
S25	(MH "Study Design") OR (MH "Cross Sectional Studies") OR (MH "Prospective Studies+")
S24	TI random* or AB random*
S23	TI placebo* or AB placebo*
S22	(MH "Placebos")
S21	TI tripl* n5 blind* or AB tripl* n5 blind* or TI tripl* n5 mask* or AB tripl* n5 mask* or TI trebl* n5 blind* or AB trebl* n5 blind* or TI trebl* n5 mask* or AB trebl* n5 mask*
S20	TI doubl* n5 blind* or AB doubl* n5 blind* or TI doubl* n5 mask* or AB doubl* n5 mask*
S19	TI singl* n5 blind* or AB singl* n5 blind* or TI singl* n5 mask* or AB singl* n5 mask*
S18	TI clin* n5 trial* or AB clin* n5 trial*
S17	(MH "Random Assignment")
S16	(MH "Clinical Trials+")
S15	S1 and S9 and S14
S14	S10 or S11 or S12 or S13
S13	TI ( child* or carer* or caregiver* or parent* or famil* or brother* or sister* or sibling* or nanny or nannies ) or AB ( child* or carer* or caregiver* or parent* or famil* or brother* or sister* or sibling* or nanny or nannies ) or MW ( child* or carer* or caregiver* or parent* or famil* or brother* or sister* or sibling* or nanny or nannies )
S12	(MH "Child Care+")
S11	(MH "Schools, Nursery")
S10	(MH "Family+")
S9	S2 or S3 or S4 or S5 or S6 or S7 or S8
S8	(MH "Psychotherapy")
S7	(MH "Health Promotion")
S6	(MH "Health Education")
S5	(MH "Public Health")
S4	(MH "Environmental Pollution+")
S3	(MH "Medicine, Environmental")
S2	(MH "Smoking Cessation")
S1	(MH "Smoking+")

Searched February 2017
1	exp tobacco smoking/
2	Smoking Cessation/
3	Environmental Medicine/
4	exp pollution/
5	Public Health/
6	Health Education/
7	Health Promotion/
8	Psychotherapy/
9	2 or 4 or 5 or 6 or 7 or 8
10	exp Family/
11	exp health education/
12	day care centers/ or child day care/
13	Child Care/
14	(child* or carer* or caregiver* or parent* or famil* or brother* or sister* or sibling* or nanny or nannies).ti,ab.
15	10 or 11 or 12 or 13 or 14
16	1 and 9 and 15
17	limit 16 to 100 childhood <birth to age 12 yrs>
18	limit 17 to yr="2007 ‐Current"
19	(2011* or 2012*).yr,dp.
20	18 and 19

Methods	Country: Hong Kong, China  Setting: community (maternal and child health centres)  Type: RCT
Participants	952 parents from a birth cohort who were listed as smokers in the '1997 Birth Cohort Study' of the Department of Community Medicine, University of Hong Kong
Interventions	Intervention: 20 to 30 minutes of telephone counselling with information based on individual needs; no NRT information given unless asked, and even then, information given was kept minimal. Stage‐based printed self‐help materials (based on baseline) provided just once.  Control: Recieved stage‐based printed self‐help material only.
Outcomes	At 6 months:  • Parental quitting: self‐reported 7‐day prevalence quit rate, self‐reported 24‐hour point prevalence quit rate, self‐reported continuous abstinence rate, biochemically validated (CO or urine cotinine or both) quit rate, reported implementation of total or partial smoking ban at home
Type of intervention	Well‐child (child health check)
Notes	Retention: 837/952
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomised; method not described
Allocation concealment (selection bias)	Low risk	Numbered sealed opaque envelopes
Incomplete outcome data (attrition bias)   All outcomes	Low risk	Losses to follow‐up 11% intervention/4% control. Included as continuing smokers
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	"Independent interviewer...was unaware of subjects' group allocation... All respondents who reported they were not smoking during the preceding 7 days were invited to attend the research centre for biochemical validation."

Methods	Country: Shanghai, China Setting: community (households) Type: RCT
Participants	318 households with smoking parents or caregivers who had children aged 5 years or younger at home
Interventions	Intervention: • Counselling, conceptualised on the basis of the protection motivation theory developed by Rogers 1975 • Smoking hygiene intervention (SHI) with brief advice to quit SHI: • Keeping child away from household members' and other people's smoke • Avoiding smoking in the car or in closed areas near the child • Not taking the child into smoky environments • Enforcing a strict no‐smoking policy at home and in the car Control: • Placebo intervention included counselling on child development issues • No SHI or second‐hand smoke (SHS) exposure reduction or quit smoking counselling provided by the study counsellor. When queries on smoking or SHS were raised by participants, they were given the hotline number of the Shanghai CDC's smoking cessation clinic.
Outcomes	Child exposure: Primary outcomes at 6 months: • Participant‐reported improvement in smoking hygiene in the household (smoking restriction by household members at home) • Reduced exposure of child to SHS inside the home measured by mean number of cigarettes per week • Reduction in children's urine cotinine concentrations Secondary outcomes: • Total SHS exposure to child from all smokers inside and outside the home • Household members smoking cigarettes around the child • Smoking behaviour of household members (reducing the mean number of cigarettes smoked daily, making a quit smoking attempt for at least 24 hours, and quitting smoking) Child illness: Respiratory illness incidence among children as reported by key household members Target behaviour change: Secondary outcome at 6 months: • Smoking behaviour of household members (reducing mean number of cigarettes smoked daily, making a quit smoking attempt for at least 24 hours, and quitting smoking). Verified by CO measure
Type of intervention	Community‐based
Notes	Conflict of interest: none declared Source of funding: Flight Attendant Medical Research Institute (FAMRI), USA, grant 072233_CIA; and American Academy of Pediatrics, Julius B. Richmond Center of Excellence
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random numbers were computer‐generated by the project manager (not counsellors) before participant recruitment.
Allocation concealment (selection bias)	Low risk	Counsellor opened a serially numbered, opaque, and sealed envelope to reveal the random assignment of each smoker to intervention or control group.
Incomplete outcome data (attrition bias)   All outcomes	High risk	Large dropout rate; more than 40% of the households in each group were not available. This was the result of many households relocating to a new residential area, farther from the original study area. Analysis does not appear to be intention‐to‐treat.
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	Not blinded but objective measure (cotinine)
Other bias	High risk	In addition to dropout rate: • Small possibility of cross‐contamination between intervention and comparison groups • Dosing (i.e. contact duration and frequency) of the intervention was not equal for the intervention and comparison groups • Social desirability bias due to interview format

Methods	Country: Australia  Setting: community (child health nurse home visits)  Type: RCT
Participants	181 women recruited from a postnatal ward who had given birth to a single live infant, identified as 'at risk' (1 or more of identified physical domestic violence, identified childhood abuse by either parent, sole parenthood, or ambivalence to pregnancy; as well as 3 or more of maternal age < 18 years, unstable housing, financial stress, poor maternal education, low family income, social isolation, history of mental health disorder, drug or alcohol abuse, and domestic violence other than physical abuse)
Interventions	Intervention: • Home‐based intervention focused on establishing trust with families, enhancing parenting self‐esteem and confidence, providing guidance for child development including crying and sleep behaviour, promoting preventive child health care and facilitating access to child health centres • Weekly home nurse visits for first 6 weeks, fortnightly for 3 months, then monthly until 6 months postpartum  Control: • Usual care
Outcomes	At 4 months: • Health outcomes only reported at 12 months  • Maternal self‐report of smoking behaviour and observations by research assistants of smoking behaviour in the home  • Child health questionnaire
Type of intervention	Well‐child (peripartum)
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"A random number table was computer generated."
Allocation concealment (selection bias)	Low risk	The random number table was "used by a clerical officer not involved in determining eligibility to determine intervention status".
Incomplete outcome data (attrition bias)   All outcomes	Low risk	Similar rates of retention at 12 months in both arms (76% intervention, 77% control)
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	"Data were collected in the home by a researcher who was naive to the intervention status of the participants and was not involved in providing healthcare to the participants."

Methods	Country: Iran Setting: recruited from health centres, intervention face‐to‐face/on phone RCT
Participants	130 families with healthy infants younger than 12 months
Interventions	Intervention: • Counselling (motivational interviewing) of mothers and fathers Control: • Usual care (health visits for checking infant's growth and developmental milestones) • Parents given a pamphlet and sticker depicting a smoke‐free home
Outcomes	Infant urinary cotinine at baseline and at 3 months Change in parental smoking Home and car smoking bans
Type of intervention	Well‐child (child health check)
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No information provided
Allocation concealment (selection bias)	Unclear risk	No information provided
Incomplete outcome data (attrition bias)   All outcomes	Low risk	4/65 lost to follow up in control group and 5/65 in intervention group
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	The statistical analyst and outcome assessors were blinded to the group assignment, the control group was uninformed of the counselling processes.

Methods	Country: USA Setting: community (home) Type: RCT
Participants	165 caregivers and their infants born at ≤ 32 weeks' gestational age, within 6 weeks of discharge from the NICU
Interventions	Intervention: • Counselling provided by 1 of 2 research nurses trained in motivational interviewing and actively supervised by an expert in the field • Sessions included smoking cessation or relapse prevention counselling for willing caregivers who were current or former smokers, while second‐hand smoke exposure control efforts were explored and reinforced for all • Motivational interviewing technique used: elicit‐provide‐elicit • Trialists also offered information on resources (e.g. smokers quit line, pharmacotherapy) Control: • Brief asthma education at baseline only
Outcomes	Child exposure: • Postintervention infant exposure to second‐hand smoke assessed via caregiver‐reported data from survey that occurred closest to completion of the intervention (5‐month survey) • Salivary cotinine samples obtained at study end (8 months after NICU discharge) used as an objective measure of infant SHS exposure Child illness: • Respiratory symptoms assessed by asking caregivers to quantify in the past 2 weeks number of days with wheeze/cough, number of nights awakened because of wheeze/cough, number of days having taken rescue medication, and number of symptom‐free days Child health service utilisation: • Asked caregiver about numbers of visits to primary care provider and emergency department, and hospitalisations for wheezing or breathing problems since the prior survey Target behaviour change: • Smoking ban in home/car, caregiver confidence, and motivation to quit smoking
Type of intervention	Community‐based
Notes	Conflict of interest: none declared Source of funding: grant from the Halcyon Hill Foundation (Halterman, PI), which had no involvement in submission of this manuscript for publication
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method not specified
Allocation concealment (selection bias)	Low risk	Concealed envelope system, stratified by caregiver‐reported routine infant SHS exposure
Incomplete outcome data (attrition bias)   All outcomes	Low risk	12.7% of participants dropped out (18.1% in the treatment group vs 7.3% in comparison group)
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	Assessments were completed by study team members blinded to the infants' randomisation category. Objective measure also used (cotinine)

Methods	Country: USA Setting: recruited from various sites including hospital in‐patient settings and clinics, Latino cultural events. Intervention involved counselling visits and phone calls. Type: RCT
Participants	Latino caregivers who smoked and had a child with asthma
Interventions	Group 1: Behavioral action model (BAM). This was modelled on clinical guidelines for smoking cessation. The model focused on increasing the smoker’s self‐efficacy to quit by teaching problem solving and coping skills. Group 2: Precaution adoption model (PAM). This model used feedback on the caregiver’s carbon monoxide level and the child’s second‐hand smoke exposure, using motivational interviewing techniques. Eight weeks of transdermal nicotine patches were available free of charge if participants were ready to quit.
Outcomes	Passive nicotine monitors at baseline and at 3 months after completion of treatment Level of functional morbidity due to asthma Smoking cessation by caregiver; self‐report and expired air CO concentration (continuous abstinence, 7‐day point prevalence abstinence)
Type of intervention	Child with health problems (respiratory disorders)
Notes	Attrition 37/133
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomised by computer‐generated sequence
Allocation concealment (selection bias)	Unclear risk	No information provided
Incomplete outcome data (attrition bias)   All outcomes	High risk	Attrition 37/133
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	Self‐report assessments administered by research assistants blinded to the treatment condition
Other bias	High risk	Selection bias. Some participants were enrolled from other studies, so it may be difficult to elicit study‐specific effects. Inconsistencies in presentation of data: BAM group (n = 68) had results for n = 49 at the end of the study, and not all were accounted for. Similarly in the PAM group, n = 65 and completed n = 49 at end of treatment, and not all were accounted for. Outcomes presented for 'acculturation' and 'asthma morbidity', but no details on how these were assessed.

Methods	Country: USA Setting: community (home and telephone) Type: RCT
Participants	560 smoking primary caregivers (parents) of both children with asthma and healthy children
Interventions	• Precaution adoption model intervention (PAM; motivational interviewing to deliver feedback on child's second‐hand smoke (SHS) exposure and smokers' carbon monoxide levels and cessation induction strategies). • Home visit (for aim 1/teachable moment): Parents of children with asthma received NIH guideline‐based asthma education, while parents of healthy children received child wellness counselling. All participants received identical smoking cessation counselling via motivational interviewing. Verbal and graphical feedback was provided regarding smoking level, carbon monoxide level, how quitting could reduce disease risk and symptoms, the child's SHS exposure, risk of smoking on the child's SHS exposure, and how risks could be reduced by quitting smoking or reducing SHS exposure. • Telephone counselling (for aim 2/intervention intensity): Both PAM and enhanced PAM received six 15‐ to 20‐minute calls regarding asthma symptoms and management for 4 months after the home visits. Enhanced PAM also received smoking cessation and a second round of SHS exposure feedback.
Outcomes	Child exposure: 2 passive nicotine monitors (dosimetry) placed for 1 week during each of the 2 measurement periods (baseline and after call 5) ‐ 1 in the room where the child spends the most time and 1 worn by the child. Parent‐reported SHS exposure assessed by structured interview Child illness: asthma morbidity (numbers of asthma‐related hospitalisations, school days missed due to asthma, days with asthma symptoms, and Asthma Functional Morbidity Scale scores) Child health service utilisation: asthma‐related hospitalisations Target behaviour change: proportion of participants who quit; verified by expired air carbon monoxide testing at all follow‐up intervals
Type of intervention	Child with health problems (respiratory disorders)
Notes	Conflict of interest: none declared Source of funding: NIH grant R01 HL062165‐06
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Urn randomisation (form of adaptive biased‐coin randomisation)
Allocation concealment (selection bias)	Low risk	Allocation sequence could not be accessed by staff.
Incomplete outcome data (attrition bias)   All outcomes	High risk	Although no significant difference was seen in the counselling call completion rate, this rate was only 55% by 12‐month follow‐up.
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	Objective measure used ‐ air nicotine
Other bias	High risk	• At baseline, comparison group (healthy children) was significantly different from the 2 intervention groups (PAM and enhanced PAM) with respect to child and parent age, cigarettes smoked per day, years smoked, nicotine dependence, and % household smoking ban. Note that randomisation only occurred for the 2 intervention arms. • Potential detection bias in that the half‐life of carbon monoxide is 4 to 6 hours, and so 7‐ and 30‐day point prevalence abstinence cannot be verified beyond that time frame.

Methods	Country: USA Settings: hospital and home RCT (3 arms)
Participants	Inner city families with a child aged 6 to 12 years with asthma, residing with a smoker
Interventions	Health coach/air clear group: two air cleaners and four 30‐ to 45‐minute nurse health coach home visits, and a behavioural intervention to reduce child second‐hand smoke exposure Air cleaner group: two air cleaners and 4 asthma education sessions Control group: asthma education during 4 nurse home visits
Outcomes	Six‐month follow‐up from baseline: • Child urinary cotinine at baseline and at 6‐month follow‐up • Asthma symptom‐free days • Acute asthma healthcare events • Change in air quality • Caregiver smoking frequency and location
Type of intervention	Child with health problems (respiratory disorders)
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomised in 1:1:1 ratio with random block sizes; randomisation performed by study co‐ordinator using the function in the database
Allocation concealment (selection bias)	Low risk	All study staff, including all investigators, were blinded to subsequent group assignment.
Incomplete outcome data (attrition bias)   All outcomes	Low risk	91.3% followed up
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	All study staff, including all investigators, were blinded to subsequent group assignment.
Other bias	High risk	Children randomised to the control group had caregivers who smoked significantly more at baseline and follow‐up than those in either intervention group.

Methods	Country: Hong Kong, China  Setting: hospital (paediatric wards/outpatient settings)  Type: RCT
Participants	80 parents of sick children presenting to a clinic or admitted to a children’s ward of a major Hong Kong hospital
Interventions	Intervention: individualised motivational intervention for 30 minutes with nurse counsellor; appropriate stage‐matched intervention used to "increase motivation and lower resistance to quit"; telephone reminder 1 week after the intervention  Control: healthy diet counselling for their sick children as a placebo intervention
Outcomes	One‐month follow‐up:  • Parent report of daily cigarette consumption in past 30 days
Type of intervention	Child with health problems (ill‐child health care)
Notes	Retention: 77/80
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Randomized controlled trial"; no further information provided
Allocation concealment (selection bias)	Unclear risk	Randomised after completion of questionnaire; no further information provided
Incomplete outcome data (attrition bias)   All outcomes	Low risk	Low loss to follow‐up: 77 (of 80) participants followed‐up successfully
Blinding of outcome assessment (detection bias)   All outcomes	Unclear risk	"At 1 month, trained interviewers who were blinded to the group assignment delivered telephone follow‐up calls to both groups to evaluate the primary and secondary outcomes using a standardized questionnaire." Self‐reported outcome only; bias possible

Methods	Country: Italy  Setting: well‐child, in the community  RCT
Participants	218 women 30 to 49 years of age with children
Interventions	Brief counselling and 3 gifts. Both groups received self‐help booklet.
Outcomes	Reported smoking restrictions in home and car Change in smoking status reported
Type of intervention	Well‐child (child health check)
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random number table used
Allocation concealment (selection bias)	Unclear risk	Not stated
Incomplete outcome data (attrition bias)   All outcomes	Low risk	12 of 218 lost to follow‐up and ITT analysis performed
Blinding of outcome assessment (detection bias)   All outcomes	Unclear risk	Not discussed for observer; objective measure not used

Methods	Country: Taiwan Setting: community (schools) Type: RCT
Participants	75 parent and child dyads in 6 elementary schools (grades 3 to 6); school was the unit of assignment
Interventions	Intervention: Parent‐child dyads received an interactive programme comprising 3 weekly group sessions and 1 individual telephone counselling session 4 weeks after group sessions. Control: Written materials related to tobacco information were received by mail 4 times during the same time period instead of the intervention sessions.
Outcomes	Child exposure: urine cotinine as well as parent and child reports of children's exposure to parental smoking Target knowledge change: Aims of intervention were to instil knowledge regarding the mechanism of the harmful effect of ETS, to correct people's perceptions of the smoking patterns that lead to ETS exposure at home, to introduce strategies for reducing ETS, and to assist parent‐child dyads in formulating strategies for maintaining a smoke‐free home.
Type of intervention	Community‐based
Notes	Conflict of interest: none declared Source of funding: National Science Council of Taiwan (NSC97‐2314‐B‐038‐043‐MY3)
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not stated
Allocation concealment (selection bias)	Unclear risk	Not stated
Incomplete outcome data (attrition bias)   All outcomes	Low risk	21% dropout rate
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	Single‐blind; objective measure (cotinine)
Other bias	High risk	Selection bias: differences in participation rates between intervention and control groups. Non‐simultaneous collection of self‐reported data and urine cotinine levels during post‐test 2 may have caused inconsistency in the data.

Methods	Country: USA  Setting: well baby check  RCT
Participants	103 mothers smoking ≥ 10 cigarettes/d with infants presenting to a well baby check
Interventions	Urine was collected from all infants and analysed for cotinine.  Intervention: A report of the infant's urinary cotinine level along with a personalised letter to the mother to be signed was returned to the child's doctor. The letter outlined ways to reduce child ETS exposure (identify location of smoking, wash hands after smoking, ensure day care home is smoke‐free, ask friends to avoid smoking in the presence of the infant when visiting) but did not discuss cessation. The physician called the mother by telephone to further explain the results.  Control: usual care
Outcomes	At 2 months, all participants were contacted to obtain a second urine sample from the infant for analysis.
Type of intervention	Well‐child (child health check)
Notes	Retention: 56/103 (54%)
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"randomly assigned by computer on an individual basis to intervention or control groups"
Allocation concealment (selection bias)	Low risk	See above.
Incomplete outcome data (attrition bias)   All outcomes	Low risk	High loss to follow up ‐ 43% control and 48% intervention; "however, it is unlikely that exclusion bias would mask a true impact of the intervention. Characteristics of those who complied were similar to those of the noncompliers... even with the reduced participation... the data were adequate to indicate that the response to the intervention was poor"
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	Outcomes biochemically verified

PERMALINK

Family and carer smoking control programmes for reducing children's exposure to environmental tobacco smoke

Behrooz Behbod

Mohit Sharma

Ruchi Baxi

Robert Roseby

Premila Webster

Abstract

Background

Objectives

Search methods

Selection criteria

Data collection and analysis

Main results

Authors' conclusions

Plain language summary

Summary of findings

Background

Objectives

Methods

Criteria for considering studies for this review

Types of studies

Types of participants

Types of interventions

Types of outcome measures

Outcomes for children

Outcomes for parents and carers

Search methods for identification of studies

Data collection and analysis

Assessment of risk of bias in included studies

Sequence generation (checking for possible selection bias)

Allocation concealment (checking for possible selection bias)

Blinding (checking for possible detection bias)

Incomplete outcome data (checking for possible attrition bias through withdrawals, dropouts, or protocol deviations)

Other bias (e.g. selective reporting bias)

Overall risk of bias

Results

Description of studies

1.

Intervention setting

Main target of intervention

Location of studies

Participants

Age group

Theoretical framework

Acceptability of intervention to participants

Process indicators

Biological verification of children's exposure and absorption

Length of follow‐up

Sample size

Risk of bias in included studies

2.

3.

Allocation

Blinding (detection bias)

Incomplete outcome data

Other potential sources of bias

Effects of interventions

Summary of findings for the main comparison. Summary of findings: community‐based interventions for reducing children's exposure to environmental tobacco smoke.

Summary of findings 2. Summary of findings: interventions in the ill‐child setting for reducing children's exposure to environmental tobacco smoke.

Summary of findings 3. Summary of findings: interventions in the well‐child setting for reducing children's exposure to environmental tobacco smoke.

1.1. Analysis.

Tobacco smoke exposure outcomes

Household air quality

Child health outcomes

Results according to child age

Results according to setting

Biological validation of parents' self‐report

Cost data and cost‐effectiveness

Discussion

Limitations of methods employed

Authors' conclusions

Implications for practice.

Implications for research.

What's new

History

Acknowledgements

Appendices

Appendix 1. MEDLINE (Ovid SP) search strategy

Appendix 2. Embase (Ovid SP) search strategy

Methods	Country: USA  Setting: community  RCT
Participants	143 Latino parents of children aged 1 to 9 who reported smoking at least 6 cigarettes a week
Interventions	Intervention: 6 home and telephone sessions over a 4‐month period delivered by lay trained bicultural and bilingual Latina community health workers. Focused on problem solving aimed at lowering target child's exposure to ETS in the household. Intervention methods included contracting, shaping, positive reinforcement, problem solving, and social support to assist families in achieving their ETS goals.  Control: survey completion only
Outcomes	3‐Month and 12‐month follow‐up:  • Child hair nicotine and cotinine  • Parent report of child's past month exposure from all sources in the household over previous 30 days as measured by numbers of cigarettes  • Confirmed reduction based on both parents' reports and children's hair biomarkers
Type of intervention	Community‐based
Notes	Retention: 127/143 (89%)
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"randomized"; no further details given
Allocation concealment (selection bias)	Unclear risk	Not specified
Incomplete outcome data (attrition bias)   All outcomes	Low risk	81% provided data at all assessments, "and analyses showed attrition introduced no significant biases".
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	Biochemical validation used

Methods	Country: UK Setting: hospital (antenatal clinic) Type: RCT
Participants	1051 smoking 12‐ to 24‐week pregnant women who currently smoke 5 or more cigarettes per day and who smoked at least 10 cigarettes per day before pregnancy
Interventions	Intervention: biochemically validated smoking cessation with transdermal nicotine patches (15 mg per 16 hours) for 4 weeks, followed by another 4 weeks if abstinent Control: visually identical placebo
Outcomes	Child exposure: maternal self‐reported prolonged and total abstinence from smoking validated by exhaled CO and/or salivary cotinine Child illness: birth outcomes, infant impairment, infant respiratory symptoms up to age 2 Target behavioural change: smoking cessation
Type of intervention	Well‐child (antenatal health check)
Notes	Conflict of interest: NM reports personal fees from Novartis and personal fees from Elsevier, outside of the submitted work; TC reports personal fees from Pierre Fabre Laboratories, France, outside the submitted work. Source of funding: HTA programme project number 06/07/016
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Internet‐based randomisation that was stratified by recruiting site
Allocation concealment (selection bias)	Unclear risk	All pharmacists, research staff, and trial participants blinded to treatment allocations, but unclear about allocation concealment
Incomplete outcome data (attrition bias)   All outcomes	Low risk	By 2‐year follow‐up, 14% in NRT group and 15% in control group dropped out.
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	Double‐blind and objective measure
Other bias	High risk	• Smoking data were not sought from all participants at predetermined time points, but were obtained opportunistically at multiple, different times between 8 and 54 months after childbirth, rendering smoking behaviour data difficult to interpret. • Smoking outcomes at 2 years were self‐reported, which may lead to bias; furthermore, these outcomes were not assessed in about 40% of participants.

Methods	Country: USA Setting: home Quasi‐experimental controlled study
Participants	Pregnant women in rural counties (first‐time mothers) with follow‐up until the child was 12 months old
Interventions	Intervention: home visits with the goal of promoting the health and development of first‐time mothers and infants (The Community‐Based Family Resource and Support (CBFRS) Program). The programme had 3 main foci: maternal health, child health and safety, and family functioning and parenting. Child's exposure to ETS was 1 part of this intervention. Control: received standard health department services that did not include home visits
Outcomes	Mother's reported number of cigarettes smoked per day at baseline, and when infant was aged 6 and 12 months Numbers of hospital admissions and emergency room visits, and visiting health department clinics for well‐child care Knowledge: Mother asked 6 questions (a set) about the effect of smoking on her child's growth and development
Type of intervention	Well‐child (peripartum)
Notes	Part of a wider intervention federally funded programme, which also included several interventions unrelated to ETS
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not applicable
Allocation concealment (selection bias)	Unclear risk	Not applicable
Incomplete outcome data (attrition bias)   All outcomes	High risk	Overall dropout from analysis rate was fairly low (26%), but dropout rate was higher in the control group (dropout 49/205 intervention group, 43/150 in control group). Characteristics of dropouts as a whole are described. No intention‐to‐treat analysis was carried out. Under these circumstances, attrition bias is certainly possible.
Blinding of outcome assessment (detection bias)   All outcomes	High risk	Outcomes were assessed at interview by research staff, who were independent of the intervention staff. However, outcome assessors could very likely have been aware of which groups participants were in, as this was decided geographically, and blinding is not mentioned. The paper found a positive intervention effect.
Other bias	High risk	Not an RCT, so very open to selection bias ‐ significant difference in number of years of education between groups. Not much baseline questionnaire info provided, so unclear whether e.g. knowledge re smoking differed from the start between the 2 groups

Methods	Country: USA  Setting: paediatric clinics serving ethnically diverse population of low‐income families  RCT
Participants	303 self‐identified women smokers whose children received care at participating clinics
Interventions	Intervention: During clinic visit, women received brief motivational message from the child’s clinician, a guide to quitting smoking, and a 10‐minute interview with a nurse or study interventionist. Women also received as many as 3 outreach telephone counselling calls from the clinic nurse or interventionist in the 3 months following the visit.  Control: usual care
Outcomes	3‐Month and 12‐month follow‐up:  • Maternal self‐reported 7‐day abstinence  • Maternal CO testing
Type of intervention	Mixed/not stated
Notes	Retention: 81% at 12 months
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Participants "determined their randomization group by choosing a Ping‐Pong ball out of a brown paper bag. The bag contained several Ping‐Pong balls that were either white or yellow, and the color of the selected ball indicated their study group".
Allocation concealment (selection bias)	High risk	See above.
Incomplete outcome data (attrition bias)   All outcomes	Low risk	19% lost at final follow‐up; counted as smokers. Similar numbers lost to follow‐up in both groups
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	Biochemical validation used in subset: "We determined the comparability of compliance with testing between the intervention and control groups and then examined the effect on self‐reported rates of abstinence of adjusting outcomes by the percentage of abstainers who tested above the cut‐off point."

Methods	Country: Australia Setting: community well‐child health clinic Type: RCT
Participants	1424 parents of children aged 0 to 4 years attending well‐child health checks
Interventions	Interventions: Arm 1: • Computer‐delivered care ‐ tailored on‐screen information and a printed self‐help report regarding the risks of infant SHS exposure, how to reduce exposure risk, advice on quitting smoking, and contact details of the free quit line • Child health nurse‐delivered care ‐ During the subsequent clinic consultation, nurses provided a brief intervention focussing on risk reduction for the infant and offering NRT to parents/carers who were smokers. Contact details of the quit line were again provided, and nurses discussed the importance of complete home smoking bans, providing advice to address any barriers to their implementation. Arm 2: • Same as above, plus infant urine cotinine measured and results shared with parent, child health nurse, and their GP. A guide to preventing infant SHS exposure and strategies for quitting smoking were also included. Control: • Usual care from child health nurses
Outcomes	Child exposure: Primary outcome: Parent/carer reported infant exposure to SHS, defined as a person smoking in the infant's presence in the past 3 days. At 12‐month follow‐up, if parent/caregiver reported the infant as NOT exposed, this was validated with urine cotinine test. Secondary outcomes: parent/caregiver smoking status and household smoking ban status of the home Target behavioural change: proportion who quit and proportion with complete household smoking ban
Type of intervention	Well‐child (child health check)
Notes	Conflict of interest: unclear Source of funding: Financial Markets Foundation for Children, Community Health and Anti Tuberculosis Association, Centre for Health Research & Psycho‐oncology (CHeRP and infrastructure support from the Hunter Medical Research Institute)
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Clinics were randomly assigned to 1 of 2 treatment arms or to a control arm via random number function in SAS statistical software.
Allocation concealment (selection bias)	Unclear risk	Services not blind to study allocation but unclear about allocation concealment
Incomplete outcome data (attrition bias)   All outcomes	Low risk	Between 11% and 15% lost to follow‐up or declined to participate at 12‐month follow‐up
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	Objective measure (cotinine)
Other bias	High risk	• Variability in quality and consistency of advice given to parents/caregivers to access NRT may bias the effect estimate towards the null. • Exposure misclassification; non‐smoking parents/caregivers had partners who smoked and this was not measured. Furthermore, self‐reported SHS exposure was not validated at baseline assessment. • Not blinded, meaning prone to detection and performance bias

Methods	Country: USA  Setting: telephone smoking cessation helpline  RCT. Randomised by day of the week, but counsellors blinded to the guide being used
Participants	630 smoking mothers with children younger than 6 years of age calling the helpline
Interventions	Callers to a telephone smoking cessation assistance service were randomised to receive 1 of 3 self‐help guides. One was specifically written for the target audience, another was received from the American Lung Association, and 1 was developed by the National Cancer Institute. Callers to the line received individual stage‐based counselling and were sent the guide by mail.
Outcomes	Six months later, the participant was called and was interviewed for 10 minutes about the use of the guide, opinion of the guide, quit attempts and strategies to quit, and current smoking.
Type of intervention	Community‐based
Notes	Retention: 630/873 (72%)
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Quasi‐randomised: "Guides were assigned randomly to those in the target audience based on a preassigned list randomized by the day of the week."
Allocation concealment (selection bias)	Low risk	"CIS counsellors were blinded regarding which self‐help guides subjects would receive."
Incomplete outcome data (attrition bias)   All outcomes	Low risk	28% lost to follow‐up; "completion rates were similar for subjects in the three guide groups"
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	"Follow‐up interviews were conducted by trained interviewers who were blinded regarding subject assignment.... Surrogate interviews were conducted to verify the smoking status of those who reported that they had quit smoking..."

Methods	Country: USA Setting: community (Head Start programme) Type: RCT
Participants	330 caregivers (parent or legal guardian) of children aged 6 months to 6 years who reported 1 or more smokers living in the home and who spoke English
Interventions	Intervention: motivational interviewing (MI) and education MI: over 3 months, offered caregivers 4 telephone counselling sessions (15 to 30 minutes in length each) plus 1 booster 15‐minute session after 3‐month assessment, for a total of 5 sessions Education: included EPA Smoke Free Home educational activities and materials as part of the Head Start programme, including staff training workshops about risks of and strategies for reducing SHS exposure, and expert facilitation of Head Start educational activities Control: education alone
Outcomes	Child exposure: air nicotine, salivary cotinine, caregiver‐reported home smoking ban, and smoking cessation Target behavioural change: smoking cessation and home smoking ban
Type of intervention	Community‐based
Notes	Conflict of interest: unclear Source of funding: National Heart Lung Blood Institute grant HL092901
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Block randomisation scheme of groups of 10 to ensure equal group sizes. Use of random number generator
Allocation concealment (selection bias)	Low risk	Randomisation assignments were placed into sealed envelopes, which were opened after families completed baseline surveys. Research assistants who completed assessments were not masked to the intervention condition.
Incomplete outcome data (attrition bias)   All outcomes	High risk	73% and 66% of the intervention group completed 6‐ and 12‐month assessments, compared with 85% of the education‐alone group completing both assessments.
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	Not blinded but objective measure (cotinine)
Other bias	High risk	Misclassification bias; caregiver smoking status was not verified biochemically

Methods	Country: Turkey Setting: school with intervention including telephone calls RCT
Participants	Parents of school children exposed to ETS aged 9 to 11 years attending a private primary school
Interventions	Group 1: • Parents interviewed by a psychologist trained in smoking addiction Group 2: • Parents informed of child's urinary cotinine result through a letter
Outcomes	Child urinary cotinine concentrations at 9 months from baseline
Type of intervention	Community‐based
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Participants were "randomly assigned", but method was not described.
Allocation concealment (selection bias)	Unclear risk	No information provided
Incomplete outcome data (attrition bias)   All outcomes	Low risk	Full follow‐up
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	Biological measure used

Methods	Country: USA  Setting: schools  RCT. Cluster randomisation by school
Participants	96 elementary schools in 4 states
Interventions	Trial of school‐based cardiovascular health promotion, including an intervention designed to limit child ETS exposure  Intervention: consisted of promoting adoption of a formal tobacco‐free policy for the school and providing classroom‐ and home‐based programmes for students  Control: Schools participated in the evaluation but received no recommendations for policy or for classroom‐ or home‐based interventions. Control schools were not restricted from taking up tobacco‐free policies.
Outcomes	At 2 years: • School principals (or delegates) were surveyed with respect to their school's policy on tobacco and the degree to which the policy was observed.
Type of intervention	Community‐based
Notes	Retention: 96/96; this is the CATCH study
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Ten schools at each site were randomly assigned to the control condition and 7 schools each to a school‐based intervention (food service, physical education, classroom curricula) or the school‐based plus family intervention program"; no further information given
Allocation concealment (selection bias)	Unclear risk	Not specified
Incomplete outcome data (attrition bias)   All outcomes	Low risk	100% of third grade teachers and 67% of students attended Family Fun Nights; 100% of schools remained in the dietary assessment process.
Blinding of outcome assessment (detection bias)   All outcomes	Unclear risk	Not specified

Methods	Country: USA  Setting: family home  Type: RCT
Participants	291 smoking parents (or grandparents) living with a child younger than 3 years old, recruited from hospital labour and delivery logs; community health centres and healthcare providers; self‐referral
Interventions	Intervention: received a 30‐ to 45‐minute motivational interview at the parent's home with a trained health educator and 4 follow‐up telephone counselling calls (approximately 10 minutes each), aiming to reduce household ETS exposure and to increase the smoker's level of readiness for change. Feedback was provided on baseline household air nicotine, parent's CO level, and smoking‐related respiratory symptoms. Self‐help materials targeting ETS reduction and smoking cessation strategies were also provided.  Control: self‐help materials only; cessation manual; ETS reduction tip sheet; resource guide
Outcomes	ETS exposure measured by air monitors at baseline and at 6 months  Quitting and CPD by parent
Type of intervention	Well‐child (peripartum)
Notes	Retention: 247/291 (85%)
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"A computer‐generated randomization table was used."
Allocation concealment (selection bias)	Low risk	"Randomization information was kept from study staff until the baseline assessment was completed."
Incomplete outcome data (attrition bias)   All outcomes	Low risk	ITT analysis used; similar rates of follow‐up in both groups: 123/141 control, 124/150 intervention
Blinding of outcome assessment (detection bias)   All outcomes	Low risk	ETS exposure was measured by air monitors; results did not rely on self‐report.