Evaluating the effectiveness of Smoke-Free Home SafeCare, an integrated intervention, among families at risk for secondhand smoke exposure and child maltreatment in the United States: a study protocol for a hybrid type 1 trial

Abstract

Background

Secondhand smoke exposure (SHS) and child maltreatment (CM) are preventable yet have negative lifelong impacts on health. When considered together, the risk for negative health outcomes may be compounded, especially for people living in low-resource settings. Evidence-based interventions exist for preventing CM and reducing SHS among families with low resources; however, no programs jointly target SHS exposure and maltreatment risk.

Methods

This study is a hybrid type 1 trial to examine the effectiveness of a systematically braided intervention to target CM risk and SHS in the home. Fifty SafeCare Providers will be randomized to deliver either standard SafeCare (i.e., the SafeCare model alone; active treatment control; n = 25) or Smoke-Free Home SafeCare (SFHSC; treatment condition; n = 25), the braided intervention that includes both SafeCare and the Smoke-Free Homes: Some Things are Better Outside intervention to N = 500 families. Aim 2 is to assess family-level outcomes. The primary outcome is a full home smoking ban, validated by air nicotine monitors; secondary outcomes include parenting and smoking outcomes. Aim 3 is to evaluate process and implementation outcomes, including cost–benefit. We will use multilevel models and ROC analyses to evaluate and validate the primary outcome. We will use tests of non-inferiority to evaluate secondary outcomes. Cost-effectiveness analyses will be used to assess cost–benefit of SFHSC.

Discussion

This study will be the first to document the outcomes of a multi-component intervention to address cumulative risk factors that impact cancer risk among children whose parents are at risk or involved in child-protective services. Integrating an evidence-based intervention that targets SHS exposure in the home with a broadly disseminated CM prevention intervention may be a sustainable way to help reduce the compounded effects of SHS in the home and CM.

Trial registration

Clinicaltrials.gov, NCT05000632. Registered on August 11, 2021.

Administrative information

Note: the numbers in curly brackets in this protocol refer to SPIRIT checklist item numbers. The order of the items has been modified to group similar items (see http://www.equator-network.org/reporting-guidelines/spirit-2013-statement-defining-standard-protocol-items-for-clinical-trials/).

Title {1}	Evaluating the effectiveness of Smoke-Free Home SafeCare, an integrated intervention, among families at risk for secondhand smoke exposure and child maltreatment in the United States: A study protocol for a Hybrid Type 1 trial
Trial registration {2a and 2b}.	This trial is registered at clinicaltrials.gov (clinical Trials.gov ID: NCT05000632)
Protocol version {3}	Trial version 2, March 2024.
Funding {4}	This trial is funded by the National Cancer Institute
Author details {5a}	Elizabeth W Perry Mohlinga, Shannon Self-Browna, Kaitlyn Koontza, Regine Haardörferb, Daniel J. Whitakera, Claire A. Spearsa, Jidong Huanga, Michele Keglerb a School of Public Health, Georgia State University b School of Public Health, Emory University
Name and contact information for the trial sponsor {5b}	The trial sponsor is the School of Public Health at Georgia State University. 140 Decatur St. SE, Atlanta, GA 30303
Role of sponsor {5c}	The sponsor had no role in the study design; collection, management, analysis, interpretation, or reporting of the data; report preparation; or publication decisions

Introduction

Background and rationale {6a}

Secondhand smoke: prevalence and impact on young children

Secondhand smoke (SHS) exposure is preventable but responsible for severe disease burden, particularly for children [1]. While the prevalence of SHS exposure has declined in the past 60 years [2], disparities in SHS exposure persist [3]. Population-level findings from the USA suggest that SHS exposure among people who were non-Hispanic Black, living below the poverty line, with less education, and children aged 3–11 was disproportionately prevalent [2, 4] and remained relatively unchanged from 2011 to 2018 years [5]. Nearly two out of five children in the USA aged 3 to 11 years were exposed to SHS between 2017 and 2018 [2, 4]. While smoke-free air laws have been enacted for public places in most states throughout the USA [6], children can still be exposed to SHS at home and in vehicles. Thus, there is a great need for SHS prevention programming in the home environment for families with young children, single parents, people living in low-resourced areas, and parents with less than a college education [7].

There is no safe level of SHS for children [8] as it is associated with a host of adverse health and developmental outcomes among children, including sudden infant death syndrome, low birth weight, premature deliveries, congenital birth defects, respiratory and middle ear infections, more severe asthma, and impaired lung growth [4, 5, 9]. SHS in childhood is associated with a higher risk for several different types of cancers [10, 11]. Moreover, children who are exposed to SHS have higher rates of behavioral problems, attention-deficit hyperactivity disorder, and reduced problem-solving compared to children who were not exposed to SHS [12, 13].

Child maltreatment: prevalence and impact on young children

Child maltreatment (CM), which includes neglect as well as physical, sexual, and emotional violence, is also a significant public health problem. The economic burden of CM in the USA is estimated to be US $2 trillion due to costs related to healthcare, the criminal justice system, child welfare, and reduced productivity potential [14]. The economic burden of CM in the USA in 2012 was higher than the costs to society related to stroke and type 2 diabetes [15], which warrants an urgent investigation into effective prevention efforts. In 2022, nearly 600,000 children in the USA were estimated to have experienced child maltreatment [16]. Young children (0–5 years) bear the highest risk of maltreatment with 66% of fatalities occurring in children under 3 years old [17, 18].

Exposure to CM can disrupt socioemotional development and negatively impact health and well-being throughout the life course. Brain imaging studies indicate that CM exposure in a child’s early years can alter the neural structure and function of the brain [19]. People who experience CM are at a higher risk of developing chronic diseases, including lung cancer and premature death from lung cancer [20]. They also have a higher risk of experiencing mental health problems compared to people who have not experienced CM [21]. Further, children living in low-resourced households are at a greater risk of experiencing CM compared to children from higher SES households [22, 23]. This may be due, in part, to direct and indirect impacts of low socioeconomic status (SES) and chronic and substantive stressors, such as employment with long hours and little pay, lack of funds for childcare, and systemic oppression [24].

Cumulative risk for children living in low SES households: SHS exposure and child maltreatment

Both CM and SHS exposure individually have severe impacts on health throughout the life course. However, when considered together and in the context of families with low resources, exposure to both CM and SHS may compound the risk of experiencing negative health outcomes in both the short- and long-term for children living in low-resourced households. Evidence-based interventions exist for preventing CM and reducing SHS among families with low resources; however, no programs jointly target SHS exposure and maltreatment risk. Families with CM are served by existing systems (i.e., state/county child-protective services or child welfare) which allow for infrastructure to disseminate and deliver evidence-based programming; however, no such systems exist for SHS. Therefore, integrating evidence-based SHS prevention into an existing evidence-based CM prevention program that is widely disseminated in child-protective service systems could be one way to achieve public health impact if an integrated program is effective.

Interventions targeting two or more health outcomes

In 2022, the Cancer Moonshot, an initiative of the National Cancer Institute, was renewed to marshal resources to reduce the cancer death rate by half in the following 25 years [25]. In their recent manuscript, Villalobos and Chambers (2023) challenged the field, that to better advance cancer outcomes and reach Cancer Moonshot 2047 goals, delivering multiple interventions in an integrated way for multiple populations versus implementing siloed, single disease-focused interventions for one population at a time are urgently needed [26]. Integrated interventions, especially those where there is synergy, also support the movement toward whole-person care, where multiple factors are considered to promote health or disease rather than looking at separate organs and body systems. Ultimately, Villalobos and Chambers suggested that studying multi-component interventions could increase external generalizability, address limited capacity challenges, and achieve greater public health impact.

Best practices based on current evidence to integrate multiple interventions suggest that interventions can be bundled or blended. The bundled approach means to deliver interventions simultaneously or intentionally sequenced over time to address multiple health outcomes [26]. The blended approach means that components from two or more interventions have been integrated into a holistic intervention. Systematic braiding, developed by Guastafero and colleagues (2017) and subsequently tested [27, 28], is one existing approach to blend two interventions targeting multiple health risks into a holistic intervention. This approach focuses on maintaining fidelity to the curriculum for each model and the programs’ implementation infrastructure. There are four phases of systematic braiding: phase 1: content development; phase 2: rapid prototyping and development of assessment tool; phase 3: acceptability and feasibility pilot; phase 4: gather feedback and modify curriculum; and phase 5: test braided intervention in a larger randomized trial.

Objectives {7}

This study will be the first to document outcomes of a systematically braided intervention to address cumulative risk factors that impact cancer risk among children whose parents are at risk for CM or are involved in child-protective services as the result of CM. There are three aims of this study; this protocol paper focuses on the study protocol only for aims 2 and 3.

Aim 1 of this study (completed in 2022) was to use systematic braiding to integrate Some Things are Better Outside, a brief evidence-based intervention to reduce SHS exposure by reducing in-home smoking, with SafeCare®, an evidence-based positive parenting program to reduce child maltreatment. During aim 1, the integrated intervention Smoke-Free Home SafeCare (SFHSC) was piloted with ten families and the curriculum was refined by 10 SafeCare providers. For a more in-depth description of the methods and results of aim 1, please see [29].

The goal of aim 2 (data collection in progress) is to evaluate the impact of SFHSC on (a) the establishment of a smoke-free home, (b) the maintenance and sustainability of a smoke-free home, and (c) parenting outcomes among child-protective services-involved and high-risk families with a child under age 6. We will compare two treatment groups: Standard SafeCare (as usual) and Smoke-Free Home SafeCare. Our hypotheses for aim 2 are as follows: (1) the SFHSC intervention will be more effective in establishing a full home smoking ban than the Standard SafeCare intervention and (2) SFHSC will be as effective as Standard SafeCare in improving parenting outcomes (i.e., non-inferiority [30], Hahn, 2012).

The goal of aim 3 (data collection in progress) is to examine process measures to assess implementation fidelity and cost differences between SFHSC and standard SafeCare and the potential scalability of SFHSC. We hypothesize that SFHSC providers will achieve equivalent SafeCare fidelity ratings to standard SafeCare providers. We anticipate that SFHSC will have increased costs due to delivery time but that the reductions in secondhand smoke exposure will offset the costs. We expect that the added costs of SFHSC will be smaller than the added benefits of SFHSC. We expect that SFSC will also be highly cost-effective, with its benefits outweighing its costs. For aim 3, we will also assess relevant participant-level implementation outcomes, including parent engagement and satisfaction.

Trial design {8}

The current study is a hybrid type 1 implementation effectiveness parallel group cluster randomized trial. We will use block randomization and a sequence of computer-generated random numbers to allocate SafeCare Provider to either group (1:1 allocation ratio). For our main outcome (i.e., smoke-free home rules), we will be using superiority analysis; for secondary outcomes (i.e., parenting outcomes), we will be using non-inferiority analyses.

Methods: participants, interventions and outcomes

Study setting {9}

The project takes place in states with medium to high rates of adult cigarette use, according to the CDC [31] that also have an ongoing SafeCare implementation that has been sustained for at least 1 year. States that have met these criteria and have SafeCare agencies enrolled in the study include Texas, Arkansas, Colorado, Arizona, Pennsylvania, Montana, Iowa, and Oklahoma. SafeCare agencies serve both Spanish- and English-speaking families, so we have created parent materials in both English and Spanish. Additional partnerships with SafeCare agencies in other states that fall under inclusion criteria may be established based on recruitment needs and saturation of the workforce. Accredited SafeCare agencies in the states where the study is taking place serve both at-risk and families involved in child-protective services (CPS). CPS-involved families have been referred to CPS because of a CM incidence, while at-risk families have not been referred to CPS. At-risk families may be self-referred or referred to SafeCare from a community-based organization as the result of family or environmental risk factors that increase CM risk for young children. Stressors that may increase the risk for CM include mental health or substance use challenges, intimate partner violence, financial challenges, a parent/caregiver or child with disabilities, previous trauma, lack of adequate housing, multiple children under age 5 in the home, and parent/caregiver under age 20.

Eligibility criteria {10}

Parent participants are eligible if they (a) are 18 years old or older; (b) are the parent or caregiver (i.e., biological mother, biological father, legal guardian, grandparent) of a child between ages 0 and 5 (or 0 to 9 in Oklahoma, consistent with the standard implementation procedures for SafeCare Oklahoma); (c) currently smoke tobacco products (i.e., cigarettes, cigars, little cigars/cigarillos, or e-cigarettes/vapes) or have someone in the home for more than three nights a week who smokes any tobacco product; (d) allow smoking in the home sometimes; and (e) have not finished more than two sessions in at least one of the SFHSC eligible modules (i.e., Safety or Health). Both Spanish- and English-speaking families are eligible to participate in this study as we have Spanish and English versions of intervention materials.

Provider participants are eligible if they (a) completed the SafeCare workshop and have completed or are in progress for field Certification (standard National SafeCare Training and Research Center (NSTRC) criteria for delivering SafeCare) and (b) are employed at an accredited SafeCare agency. Providers will be excluded from the study if they disclose plans for significant employment leave, resignation, or promotion to a position that does not include direct clinical services during the study period.

Who will take informed consent? {26a}

The Institutional Review Boards at Georgia State University and Emory University granted ethical approval for all research activities. Research staff will obtain informed consent from all potential parent and provider participants over the phone. SafeCare providers who express interest in study participation following an informational webinar will be contacted via phone by a member of the research team to verbally go over the details of the study procedures, incentives, risks, benefits, and voluntariness and answer any questions. Providers who are interested in participating will be emailed the IRB-approved consent form and will discuss the details of the study procedures, incentives, risks, benefits, and voluntariness with a research team member over the phone. Similarly, the research team will contact interested parent participants by phone and will verbally go over the details of the study procedures, incentives, risks, benefits, and voluntariness and answer any questions. If a provider or parent chooses to participate during the consent phone call, he or she will verbally indicate their consent and their response will be recorded. The parent will be emailed a copy of the informed consent form. After verbal consent is obtained, the baseline assessment will be conducted for parents and the providers will be asked to complete the provider demographics.

Additional consent provisions for collection and use of participant data and biological specimens {26b}

This trial does not involve collecting biological specimens for storage.

Interventions

Explanation for the choice of comparators {6b}

Two interventions are being tested in the current trial: standard SafeCare (i.e., the SafeCare model alone; active treatment control) and Smoke-Free Home SafeCare (treatment condition), the braided intervention that includes both SafeCare and the Smoke-Free Homes: Some Things are Better Outside (SFH) intervention. Standard SafeCare was chosen as the comparator because the purpose of the study is to evaluate the intervention effects of the added SHS prevention program integrated into SafeCare. Below, we describe the individual interventions and then describe Smoke-Free Home SafeCare, the integrated intervention that is being evaluated in this study.

Intervention description {11a}

The SafeCare model

SafeCare is an 18-session home-based behavioral parenting program for parents of children ages 0 to 5 that addresses skills related to promoting positive parenting practices and reduced child maltreatment [32–34]. SafeCare is delivered in the home in both child-protective service settings and high-risk prevention settings by home visitors (i.e., SafeCare Providers) and is implemented in 29 US states and 8 countries. If a person is experiencing housing instability or housing challenges, sessions may take place in a location where the participant does not live, or virtually, at the discretion of the SafeCare provider. The specific setting in which SafeCare is delivered (at-risk prevention or CPS-involved) depends on the agency’s funding source.

SafeCare consists of 18 sessions, typically delivered weekly, divided into 3 modules (6 sessions per module). The three modules teach skills related to (1) parent–child/parent–infant interaction (PCI/PII), (2) home safety, and (3) child health. The parent–child interaction module targets behaviors to promote a safe, stable, nurturing relationship, and encourage social and emotional health in children through establishing daily routines and play activities. The home safety module offers parent education on common home hazards to promote a safe home environment for children. In this module, the provider and parent work together to identify and eliminate safety and health hazards and discuss the importance of parent supervision. The Child Health module offers parent education on common childhood illnesses and injuries; providers help parents implement a structured decision-making process to determine when and how to care for their child when sick or injured. In each module, SafeCare Providers use the explain-model-practice-feedback approach to teach the parent target SafeCare skills [35].

As part of NSTRC Implementation standards, fidelity monitoring occurs monthly for SafeCare Providers and is assessed by Certified SafeCare Coaches and Trainers (more about fidelity monitoring of SafeCare is described in aims 2 and 3).

Smoke-free homes: some things are better outside (SFH)

SFH is a brief evidence-based 6-week intervention that is effective in promoting home smoking bans and reducing secondhand smoke among people living in the USA [36–38]. SFH is made up of four parts: one mailing of print materials, followed by one 15–20-min coaching call, followed by two additional mailings of print materials that are sent to the participant. In the coaching call, the coach provides strategies to encourage and lead the participant through the five-step guide to creating a smoke-free home. The main outcomes of SFH are to create a smoke-free home and reduce secondhand smoke exposure, not smoking cessation; however, there are smoking cessation materials and support included in the print materials. SFH is grounded in Social Cognitive Theory and the Transtheoretical Model Stages of Change and uses persuasion, role modeling, goal setting, environmental cues, and written and verbal reinforcement of actions. Fidelity monitoring of the coaching call is a standard part of SFH implementation.

Smoke-Free Home SafeCare

Smoke-Free Home SafeCare (SFHSC) was developed by systematically braiding SafeCare and SFH, piloted, and refined during aim 1 of this study [29]. SFHSC consists of the standard three six-session SafeCare modules (i.e., parent–child/infant interaction, home safety, and child health) over 18 sessions, but includes the SFH intervention braided into the either Safety or Health module. The order of delivery for each module and the specific braided module used is determined by the provider. SFHSC is delivered by certified SafeCare providers or trained providers working toward certification who are employed by accredited agencies already delivering SafeCare in CPS or at-risk prevention settings, depending on the agency. Providers in the SFHSC condition receive additional training and coaching to deliver SFHSC before delivering the intervention and throughout the study. The initial and ongoing provider training process for providers in both study conditions is described in detail below.

Intervention training and support for providers

Standard SafeCare

All SafeCare providers taking part in the trial will have completed the SafeCare Provider workshop, which is an NSTRC training and implementation requirement for all SafeCare providers. Before their first research family, providers in the Standard SafeCare group will be asked to complete a preparation call with the research team to discuss study procedures. Providers can earn US $20 for participating in this task. Apart from the preparation call, no additional training beyond standard SafeCare implementation coaching will be required. As part of standard SafeCare implementation fidelity monitoring requirements, all standard SafeCare providers will be asked to take part in one fidelity assessment per month with their assigned SafeCare Coach for their organization. Fidelity will be assessed via standard implementation procedures, which include uploading session recordings to the SafeCare portal, their coach listening to the session and rating fidelity on the SafeCare fidelity monitoring form, followed by a meeting where the coach and provider discuss their fidelity and the coach offers the provider positive and corrective feedback.

Smoke-Free SafeCare

Providers in the SFHSC group will receive an additional 3-h workshop delivered virtually by senior trainers at the NSTRC who will also act as SFHSC coaches for fidelity monitoring (see below for more details on the fidelity). SFHSC providers will be compensated US $150 for completing the SFHSC workshop. Before serving their first SFHSC family, the providers will have one preparation call with their SFHSC coach to discuss study procedures and ensure that the provider is prepared to deliver the content of the SFHSC sessions. Providers will then have a coaching meeting with their SFHSC coach to discuss fidelity monitoring for their first two sessions with their first two SFHSC families (four sessions total, 45–60 min per session). When a provider achieves fidelity with two SFHSC families (85% fidelity or above), they will be certified in SFHSC. SFHSC Providers will be compensated US $100 for completing the pre-session call and four coaching meetings to review the fidelity assessment (US $20 per task). To ensure continued fidelity for SFHSC, there will be one additional fidelity assessment conducted for the remaining research families that each SFHSC provider serves. SFHSC providers will be asked to record and upload every SFHSC session for every family to the SafeCare portal. The SFHSC coach will then select one session to review the remaining families for each provider.

Provider support for hybrid project research tasks

Providers in both conditions will be asked to participate in one refresher training on study methods per year throughout the study period. Separate research refresher training will be offered for SFHSC providers and providers in the Standard SafeCare condition. During the training, the research team will review study tasks, procedures, and intervention materials. The providers will also have the opportunity to ask questions and share the challenges and successes they are facing so the research team can help support and problem-solve collaboratively. Providers will be compensated US $60 for attending each 1-h refresher training.

Criteria for discontinuing or modifying allocated interventions {11b}

The research team piloted the integrated intervention during aim 1 of the study and made modifications. Both interventions are evidence-based, minimal risk, and broadly disseminated. Given this, the interventions will not be modified during the trial.

Strategies to improve adherence to interventions {11c}

The research team will maintain regular contact with both provider and parent participants throughout the research study. As part of NSTRC SafeCare training implementation standards, the providers are also trained in rapport building and cultural competency with the parents, which serves as a strategy to improve adherence to SafeCare.

Relevant concomitant care permitted or prohibited during the trial {11d}

Relevant concomitant care is not applicable to this study.

Provisions for post-trial care {30}

No injuries are expected during this study. Participants are instructed in the informed consent form to contact the research team as soon as possible if they feel they have been harmed. There are no provisions for any ancillary and post-trail care, and no funds have been set aside to compensate participants if they have been harmed.

Outcomes {12}

Outcomes for aim 2

A description of measures, relevant intervention components, assessment time points, and associated intervention for aim 2 outcomes are presented in Table 1. Below are additional descriptions of the measures.

Table 1.

Aim 2 primary and secondary outcomes for the hybrid type 1 trial evaluating Smoke-Free Home SafeCare

Construct	Primary or secondary outcome	Relevant intervention component	Description	Baseline	8 weeks	20 weeks	1 year
Smoke-free home rules	Primary	SFH	Self-reported presence of a full home smoking ban. Participants had a full smoking ban if smoking was not allowed anywhere inside their home [38]	X	X	X	X
Validation of smoke-free home rules	Primary	SFH	Measured using a passive air nicotine monitor in the family’s home [38]		X		X
Additional information about smoke-free home rules	Secondary	SFH	Self-reported smoking bans in vehicles, enforcement of smoking bans in the home and vehicles, types of tobacco products included in the smoking ban, exceptions to smoke-free home/vehicle rules, type of living arrangement, and confidence and importance of establishing smoke-free home rules [36, 38]	X	X	X	X
Positive parenting behaviors	Secondary	SafeCare	Self-reported parenting behaviors will be measured using the Parenting Young Children Survey (PYCS; [39]. The PYCS is a validated scale to measure proactive positive parenting, limit setting, and supporting positive behavior	X	X	X	X
Parenting stress	Secondary	SafeCare	Self-reported parenting stress will be assessed using the Parent Stress Index (PSI) Short Form [40]. The PSI is a validated 36-item scale to measure stress in parenthood, such as parent distress, dysfunctional interactions, and stress associated with having a difficult child	X	X	X	X
Perceived general stress	Secondary	SafeCare and SFH	Self-reported perceived stress will be assessed using the Perceived Stress Scale [41]. The PSS is a validated scale used to assess nonspecific, appraised levels of stress in the past month	X	X	X	X
Child health assessment	Secondary	SafeCare	The Child Health Assessment consists of 15 items adapted from [42], which measures self-perceived knowledge when having a sick child and self-efficacy for parents when a child is sick	X	X	X	X
Parent supervision and injury questionnaire	Secondary	SafeCare	The Parent Supervision and Injury Questionnaire is a 17-item measure that assesses parent knowledge and self-efficacy about supervision, frequency of injuries by category (e.g., burns, falls, cuts, crushing injury, electrical outlet, poisoning), and frequency of doctor and emergency room visits. These items were used in previous SafeCare research [43]	X	X	X	X
Tobacco product history and current use	Secondary	SFH	Current tobacco use and previous use and exposure to SHS will be assessed using up to 19 items that have been used in Smoke-Free Homes: Some Things Are Better Outside research [36–38]. Items assess who smokes in the home if the participant has ever lived in the same household as someone who smoked, tobacco products ever used and currently used by the participant; how many days in the past week anyone has smoked in the same room as the child; and tobacco products currently being used in the home by the participant or someone else living in the home	X	X	X	X
Smoking cessation	Secondary	SFH	Smoking cessation will be assessed using seven items that have been used in Smoke-Free Homes: Some Things Are Better Outside research [36–38]. Items assess past cessation attempts, types of tobacco products the participant tried to quit using, including when the last cessation attempt was, how many times the participant attempted to quit, how many times the participant stopped smoking for more than one day, methods and resources used to help quit, and medications currently being used to help quit	X	X	X	X
Covariates	NA	NA	Standard demographics for parents include age (parent and child), sex, gender, race, ethnicity, education, employment status, income, relationship status, children (i.e., number of children living in the home, ages of target child), living situation, disability status, and the number of smokers living in the home. Shortened demographic characteristics are asked at follow-up assessments	X	X	X	X

Primary outcome

The primary outcome measure, the current presence of a full home smoking ban, is related to the SFH intervention target and has been validated in Smoke-Free Homes: Some Things Are Better Outside research [36–38]. Participants have a full smoking ban if smoking is not allowed anywhere in the home at any time at the time of completing the assessment. A partial ban is if smoking is allowed in some places or at some times, and no ban is if smoking is allowed anywhere inside the home. We will also assess what smoking products were covered by the ban (i.e., cigarettes, cigars, little cigars/cigarillos, and electronic nicotine delivery systems (ENDS)). Self-report data on home smoking bans have been shown to be highly valid and reliable [36–38]. We also will ask when the participant began restricting the smoking ban in their home (i.e., within the past month, within the past 6 months, within the past 6–12 months, 1–2 years, 3–5 years, or more than 5 years). The self-reported full smoking ban will be further validated using a passive air nicotine monitor placed in a room where the participant spends most of their time for 7 days. Passive air nicotine monitors have been used in previous Smoke-Free Homes: Some Things Are Better Outside research [38]. The passive air nicotine monitor is placed in the room in which the family spends the most amount of time for 7 days.

Secondary outcomes

Secondary outcomes related to SafeCare intervention targets include self-reported positive parenting behaviors over the past month [39], current parenting stress [40], perceived stress over the past month [41], current self-perceived knowledge and efficacy related to child health [42], and child supervision, safety, and injuries [43].

Secondary outcomes related to SFH intervention are not overtly targeted by the intervention but are measured because they are related to the main outcome and may be related to intervention spillover effects. Secondary SFH outcomes include current environmental factors that could affect SHS (i.e., type of home, if the participant rents or owns the home, if the landlord allows smoking), current vehicle situation and smoking rules in the vehicle, and current confidence in and importance of establishing smoke-free home rules. Current and prior lifetime tobacco use of the participant, tobacco products currently being used by someone else in the home, lifetime exposure to SHS, smoking in the same room or vehicle as the child in the past 7 days, and reasons for smoking indoors will be assessed [36–38]. Lastly, smoking cessation over the past 7 days will also be measured (i.e., past cessation attempts, types of tobacco products (i.e., cigarettes, cigars, little cigars/cigarillos, and ENDS)), and methods and resources used to help quit during the last cessation attempt.

Covariates

Standard demographics for parents include age (parent and child), sex, gender, race, ethnicity, education, employment status, income, relationship status, children (i.e., number of children living in the home, ages of target child), living situation, disability status, and the number of people who smoke who are living in the home.

Outcomes for aim 3

A description of implementation and process measures and assessment time points for aim 3 outcomes are presented in Table 2. Below are additional descriptions of the measures for aim 3.

Table 2.

Aim 3 process and time and cost-benefit outcomes

Construct	Description	Participant	When data be collected	Implementation outcome type
Time diaries	Providers will be asked to complete one time diary [44] per SafeCare session for each family for the target intervention module (sessions 1-6 of Health or Safety in Standard SafeCare or the Health or Safety in SFHSC). The time diaries ask providers to indicate the time spent preparing for the SafeCare session, during the session, and post-session	Provider	After each SafeCare session in the target intervention module	Implementation outcome
Session fidelity	Fidelity monitoring is a standard part of both SafeCare and SFH. SFHSC fidelity is a combination of SafeCare fidelity and SFH fidelity items. Fidelity will be assessed by a coach and providers will also be asked to complete self-rated fidelity items. See aim 3 outcomes for more details on the fidelity monitoring processes	Provider	Self-rated is collected weekly; coach-rated fidelity monitoring is described in aim 3 outcomes	Implementation outcome
Parent engagement	Provider-reported family engagement is measured using 11 items from the SafeCare Family Engagement Survey [43]. Items assess helpfulness of SFHSC/SafeCare, if the family liked and was engaged, if the family used target skills	Provider	After each session	Process outcome

Time diaries

Provider time diaries were used in previous SafeCare research [44]. Providers will be asked to complete one time diary per SafeCare session for each family for the target intervention module via Qualtrics survey for each family a provider has who is completing Safety or Health in both study conditions. The data from the time diaries will be used for the cost analyses.

Session fidelity

Fidelity for this study will be assessed in two ways: coach-rated fidelity (NSTRC standard) and self-report fidelity for both Standard SafeCare and SFHSC. Both fidelity methods are described in detail below. As an NSTRC implementation standard, SafeCare providers are required to audio-record SafeCare sessions and submit audio recordings via the NSTRC portal. For coach-rated fidelity, certified SafeCare coaches listen to audio recordings of sessions, score each session for fidelity based on the SafeCare Provider Fidelity Checklist [45], and offer positive and corrective feedback to providers if needed. In one state, due to state regulations, the providers are unable to audio record SafeCare sessions for coach-rated fidelity. Therefore, it is standard for coach-rated fidelity with SafeCare providers in this state to be conducted in person, without audio recordings. The providers must achieve 85% fidelity to maintain SafeCare certification. Fidelity monitoring is also a standard part of the SFH intervention [36–38] and SFH fidelity will be integrated with SafeCare fidelity for the SFHSC providers.

Coach-rated fidelity

For providers in the Standard SafeCare group, session fidelity will be assessed per ongoing NSTRC implementation standards by the provider’s pre-assigned coach. Providers in the SFHSC group, however, will be asked to audio record all SafeCare sessions and submit the recordings to the SafeCare portal. After achieving SFHSC certification (described above), SFHSC fidelity will be monitored for the remaining families that a provider serves by the assigned SFHSC Coach. The SFHSC Coach will monitor fidelity by reviewing one audio recording per SafeCare provider for the remainder of the study. For SFHSC providers in the state that does not allow audio recordings, SFHSC Coaches will rely on self-rated fidelity and maintain contact with the provider. The SFHSC providers will be rated on the combined fidelity checklist that was created for the braided intervention in aim 1 of the current study, which includes items from the SafeCare Provider Fidelity Checklist [45] and the standard SFH fidelity items [36–38].

Self-rated fidelity

To accommodate state restrictions regarding recording sessions, the study team developed self-rated fidelity items to be completed by all providers in this study. Self-rated fidelity includes items from the SafeCare Provider Fidelity Checklist [45] and SFH fidelity items [36–38]. Self-rated fidelity items for SafeCare include whether the provider performed the fidelity item and their self-rating for that item. Self-rated fidelity will be completed for each session for each family that a provider serves and will be collected via Qualtrics

Parent engagement and satisfaction

Parent engagement items will be provider-reported and split across SafeCare sessions and will be collected weekly (up to six items per session), separately for each family via Qualtrics survey, while a provider has a family in the Safety or Health module (the research module). Parent satisfaction will be parent-reported and assessed using the SafeCare Parent Satisfaction Measure [43] at the 20-week assessment time point via REDCap.

Provider exit interview

SFHSC providers will be invited to participate in a brief exit interview to gather information about the SFHSC curriculum and delivery experiences.

Provider covariates

Standard demographics for providers include age, biological sex, gender, race, ethnicity, highest level of education completed and field of study, position at agency (full-time, part-time, contractor), income, years of experience working with families and delivering SafeCare, smoking status, and smoke-free home rules.

Participant timeline {13}

Figure 1 presents the participant timeline for parents, including the time schedule of enrollment, interventions, and assessments.

Fig. 1.

Parent participant timeline for the Smoke-Free Home SafeCare Trial

Note. ^aFor standard SafeCare, the target research module (safety or health) lasts six sessions/6 weeks. The entire Standard SafeCare intervention includes three six-session modules that last 18 weeks. ^bFor SFHSC, the target research module (SFHSC safety or SFHSC health) lasts six sessions/6 weeks. The entire SFHSC intervention includes three six-session modules that last 18 weeks. ¹Indicates primary outcomes. ²Indicates secondary outcomes. *Both standard SafeCare and SFHSC consist of 3 6-week modules that take place over 18 sessions. SFHSC families receive the SFH materials braided into either the Safety or Health modules

Sample size {14}

The sample size was determined based on previous SFH research [36–38] assuming 20% attrition, adjusting for clustering using design effects (DEFF = 1.5), and accounting also for the margin of equivalence in the non-inferiority analysis [46]. Assumptions were adequate power at 0.8 with alpha at 0.05 for the primary outcome, a current self-reported full smoking ban. Using the effect size from previous smoke-free home research, together with the power analysis for the non-inferiority analysis, we calculated that we needed 500 parent participants to allow us to detect an absolute difference of 16.4% in smoke-free homes between the two study arms. We used SAS 9.4 to conduct the power calculations (PROC POWER) and general math and the formula outlined in Merbook and Teerenstra (2015) to calculate the sample size.

Recruitment {15}

To recruit providers, the research team received state-level SafeCare administrator approval to discuss the study with SafeCare Agency directors. Pending approval from agency directors, the research team scheduled a 30-min recruitment webinar to present the study to the agency director, team leads, and SafeCare providers. People who attended the recruitment webinar were compensated US $5 for their time. After the webinar, the providers had the opportunity to reach out to the research team to learn more about and consent to participate in the study. Provider consent happens on an individual basis. We have several agencies that have agreed to participate in the study; however, additional agencies may be added to the study if the research team deems it necessary for recruitment.

Once a provider is enrolled, they connect the research team to parents on their caseload who are willing to hear more about a SafeCare research opportunity. Providers share information about the research study (verbally and using fliers and/or branded magnets) with the parent either at intake or before the second session of the Home Safety or Child Health modules. If the parent is interested in learning more about participating in the research study, their provider will then help connect the parent to the research team in one of three ways: (1) the provider can call the research team directly when they are with the family, (2) parents can scan the QR code for the study on the recruitment flier and can call or text the research team, and (3) providers can share the family’s contact with the research team and the research team will contact the parent. On the initial call with an interested participant, the research team screens the parent for eligibility. All families who contact the research team receive a US $5 gift card for their time regardless of whether they are eligible, consent to participate, or choose to enroll in the study. Parents who are eligible and interested in participating in the study review the informed consent form with a member of the research team, and those who consent to participate are enrolled in the study. The provider will then continue Standard SafeCare or SFHSC with the enrolled parent. If a parent or provider chooses to not participate in the study, families will still receive SafeCare through the agency to which they have been referred as implementation at these agencies is ongoing.

Assignment of interventions: allocation

Sequence generation {16a}, concealment mechanism {16b} and implementation {16c}

Randomization takes place at the provider level and is stratified by state. Providers who consent to participate will be randomized to standard SafeCare or SFHSC using a single sequence of computer-generated (using Microsoft Excel’s rand function) random numbers. The Project Coordinator will generate the allocation sequence only once a new provider is enrolled in the study; the project coordinator will also enroll providers and assign them to intervention conditions. Providers will deliver the intervention condition to which they were randomized to parents in their caseload who choose to enroll in this study. If a parent does not want to enroll in the study, they will still receive SafeCare as part of the ongoing SafeCare implementation.

Assignment of interventions: blinding

Who will be blinded {17a}

After participants are assigned to each treatment condition, study personnel, including MPIs, Co-Is, and research staff conducting the research assessments will be blinded to the treatment condition until the database is locked. The project coordinators and the main statistician will be unmasked to handle randomization codes, deliver support for interventions, and complete reports.

Procedure for unblinding if needed {17b}

Unblinding will only happen if there is staff turnover in the project coordinator position.

Data collection and management

Plans for assessment and collection of outcomes {18a}

Aim 2 data collection

Self-reported data from parents (described below) will be collected at four assessment time points: at baseline, at 8 weeks (after completing the safety or health module), 20 weeks (after completing the entire SafeCare intervention), and after 1 year post-baseline. All self-reported parent data will be collected via REDCap virtually (either over the phone or via Zoom) with a member of the research team. Smoke-free home validation via air nicotine monitors will be collected at 8 weeks and 1 year. A parent will be mailed the air monitor, will leave the air monitor in place for 1 week, and then will mail the monitor back to the research team in a pre-paid envelope. A parent can earn up to US $220 for participating in this study (US $50 for each survey (4 surveys) and US $10 for each air nicotine monitor (two time points)).

Aim 3 data collection

We will use a combination of data collection methods to collect process (i.e., parent engagement, parent satisfaction) and implementation outcome data (i.e., cost measures and fidelity) for aim 3. Self-reported data from providers (i.e., time diaries, self-report fidelity, and parent engagement) will be collected via Qualtrics surveys. Qualtrics surveys will be sent weekly via email to a provider that has a family enrolled in the study that is completing the target intervention modules (i.e., either the Safety or Health modules). A provider will be asked to complete one Qualtrics survey per research module session (Safety or Health or SFHSC Safety or Health; six sessions) for each family they have enrolled in the study. Providers can earn US $10 for each Qualtrics survey they complete (six surveys per family, US $60 per family for completing all the Qualtrics surveys).

Fidelity monitoring is an essential part of the SafeCare implementation and SFH implementation process and is described in detail above. Typical NSTRC standards require Coach-rated fidelity assessed via audio-recorded sessions uploaded to the SafeCare portal for all SafeCare Providers. Coach-rated fidelity ratings for both intervention groups will be exported from the SafeCare portal and will be used with self-rated fidelity ratings in the analyses for aim 3. Provider self-rated fidelity will be collected via Qualtrics surveys. Parent satisfaction for each SafeCare module will be collected along with the 20-week parent self-report measures from aim 2 via REDCap.

Plans to promote participant retention and complete follow-up {18b}

To promote retention and complete follow-up, research staff will be in regular contact with research participants. We will also collect contact information of people who know the parent participant that the research team could contact in case the research team is not able to reach the parent directly.

Data management {19}

De-identified data will be collected from providers and parents through Qualtrics and REDCap. Once exported from these platforms, data will be de-identified and stored in a password-protected file in an online drive. To promote data quality, range checks will be conducted during the cleaning process.

Confidentiality {27}

All participants will be assigned a participant ID after consenting to the study. This number will be linked with identifying information in a master file kept in a password-protected folder on a secure network drive accessible only by the project coordinators. De-identified data collected from providers and parents through REDCap and Qualtrics will be securely stored, as both platforms employ high-level security measures to ensure data are protected from malicious data breaches and require a password to download the data. Once these data are downloaded, they will be stored on a secure network password-protected drive accessible only by a limited number of research team members. Data from air nicotine monitors will be entered into the downloaded datasets by the statistician. SafeCare fidelity audio recordings are uploaded directly to the NSTRC Portal, a secure, web-based data collection system used by all certified providers as part of standard NSTRC implementation. Research staff and SafeCare trainers must have a password to access the portal. Qualitative data from SFSC provider exit interviews will be de-identified and kept on a secure network drive. All research staff are trained as mandated reporters. Confidentiality will be broken only in the most extreme of circumstances; if a provider or research staff observes or learns of abusive behavior toward the child, the incident will be reported to the Department of Children and Families in the state where the mother resides.

Plans for collection, laboratory evaluation and storage of biological specimens for genetic or molecular analysis in this trial/future use {33}

The air nicotine monitors will be collected to validate self-report smoke-free home data. Air monitors will be mailed to the participant, and the participant will mail the monitor back to the research team. The research team will store the monitors in a locked cabinet and deliver them to the laboratory to assay and conduct the gas chromatographic analysis. Air nicotine monitors will have an ID number that will be linked to the participant ID in the password-protected online file, but no identifying information will be included on the monitor. The lab will then store the air monitors until the study is completed.

We will not collect biological specimens for genetic or molecular analysis in this trial.

Statistical methods

Statistical methods for primary and secondary outcomes (aim 2) {20a}

We will conduct both intent-to-treat and per-protocol analyses. We will use frequency distributions to summarize categorical data and measures of central tendency to summarize continuous data. We will assess how well randomization has created comparable groups by assessing control and intervention participants on all relevant baseline criteria (e.g., demographics and smoking behaviors) using appropriate bivariate statistics. If there is a significant imbalance between groups due to the randomization, the relevant variables will be used as control variables in the RCT analyses. All analyses will control for age, race, ethnicity, education level, and number of children. We will explore sex as a biological variable as a covariate and will retain it in the model if there is sufficient variability. All analyses will be considered statistically significant at α=0.05. Analyses will be conducted using SAS 9.4 [47] and HLM8 [48].

Primary outcome

The primary outcome of interest is self-reported home smoking rules, which will be validated with air nicotine monitor data (established using ROC analyses) at 8 weeks post-baseline (or after the SFHSC module is completed). We will use complete case data and multilevel models accounting for the nesting of participants in SafeCare providers with group assignment predicting a binary smoke-free home status (full ban/no ban). For the air nicotine monitors, time-weighted average airborne nicotine will be assayed, and the amount of nicotine collected by the air monitor will be determined in the laboratory using gas chromatographic analysis. The air nicotine monitor data will be used to validate the self-reported smoke-free home rule data at 8 weeks and 1 year (sustainability) using ROC analyses, which have been previously validated in SFH research [49]. We will assess maintenance by analyzing the 20-week self-report data and sustainability by using the self-report and nicotine monitor data to validate the self-report.

Secondary outcomes

The parenting outcomes will be assessed using a test of non-inferiority [30] to ensure that the SFH intervention does not have unintended consequences on typical SafeCare parenting outcomes. To assess non-inferiority, we will conduct models parallel to the effectiveness analyses, estimating standardized intervention effects for both groups for each of the child–parent relationship quality indicators for parent–child relations (measured by PYCS) [39] and parenting stress (measured by the PSI) [40]. Non-inferiority is established if the upper bound of the one-sided 90% CI is below the margin of equivalence, d = 0.30. If non-inferiority is established, we will assess the superiority of SFHSC over SafeCare using the two-sided 95% CI [50].

Statistical methods for additional analyses: implementation outcomes (aim 3)

The goal of aim 3 is to examine process measures to assess implementation fidelity and cost differences between SFHSC and standard SafeCare and the potential scalability of SFHSC. We hypothesize that SFHSC providers will achieve equivalent SafeCare fidelity ratings to standard SafeCare providers. We anticipate that SFHSC will have increased time costs in delivery, but that these will be offset by the reductions in SHS exposure. We expect that the added costs of SFHSC will be smaller than the added benefits of SFHSC. We expect that SFSC will also be highly cost-effective, with its benefits outweighing its costs. For aim 3, we will also assess relevant participant-level implementation outcomes, including parent engagement and satisfaction.

Fidelity

Fidelity will be assessed through two-level random effects models where ratings are nested in providers and the program is the key predictor. We will use the same non-inferiority approach described above in aim 2.

Time and cost–benefit

For each provider, the amount of time spent on training, delivery, and coaching will be aggregated by adding the time (in minutes) spent on training, coaching, and each time diary collected from the same individual. Using these data, we will estimate the average difference in time in training/preparation, delivery, and coaching between SafeCare and SFHSC providers. The incremental costs per abstinent household associated with SFHSC will be calculated using methods commensurate with existing cost-effectiveness smoking cessation studies[51]. Specifically, we will calculate the materials and opportunity costs for the additional time incurred for SFHSC providers, which represents the added costs per provider associated with SFHSC compared with SafeCare.

The additional number of households that become smoke-free in SFHSC compared with those in SafeCare will be obtained from the analysis in aim 2. The incremental costs per abstinent household will be calculated by dividing the total added costs for SFHSC by the additional number of households that become smoke-free under SFHSC. The estimates of healthcare costs attributable to secondhand smoke exposure at home for each child and each adult will be based on existing studies [52] and adjusted for inflation. The added benefits of SFHSC will be constructed by multiplying the healthcare savings resulting from a reduction in SHS exposure, assuming secondhand smoke exposure in homes with home smoke-free rules will be zero, measured in dollars per household, by the additional number of households that become smoke-free in SFSC. The added costs of SFSC will then be compared with its added benefits.

Parent engagement and satisfaction

Engagement and satisfaction will be assessed statistically (i.e., engagement and completion) using parallel methods to those used in aim 2 and for fidelity.

SFHSC provider edit interview

Data collected from SFHSC providers during the exit interview will be analyzed using the narrative analysis method. We will use an open-coding process with multiple coders to generate the inductive and deductive themes across and within cases. To ensure interrater reliability, research team members will simultaneously examine and code the data. Coding differences will be discussed and rectified until an inter-coder agreement threshold of 80% is achieved [53].

Interim analyses {21b}

Interim analyses will not be conducted for this trial.

Methods for additional analyses {20b}

If the sample size allows exploratory analyses, we will assess intervention impact and sustainability among relevant sub-groups (e.g., English-speaking versus Spanish-speaking) as well as moderators of the intervention effect. Moderators of interest include sociodemographic characteristics (e.g., sex as a biological variable, age), the number of people who smoke in the home, smoking history and habits, and provider experience.

Methods in analysis to handle protocol non-adherence and any statistical methods to handle missing data {20c}

Missing data patterns will be investigated. If needed, a combination of full information maximum likelihood (FIML) and multiple imputations, as suggested by the type of variables with missing data and the mechanisms identified of said missingness, may be used in the analyses. In terms of protocol non-adherence, we will conduct longitudinal analyses using mixed models, which will allow for the inclusion of all baseline participants’ data, regardless of whether they completed the intervention, through FIML estimation.

Plans to give access to the full protocol, participant-level data and statistical code {31c}

De-identified participant data will be made available at the end of the study. Statistical codes will be made available upon request.

Oversight and monitoring

Composition of the coordinating center and trial steering committee {5d}

The research team is made up of two universities that meet monthly. One university manages the majority of the day-to-day aspects of the trial and the data and provides organizational support. The other university provides additional management and logistical oversight throughout the project. The data management team is made up of a postdoctoral research associate, a research associate, and investigators from both universities: one university will oversee and manage all of the data while it is being collected and will conduct the cost-effectiveness analyses. The second university will receive de-identified data upon study completion to conduct the analyses related to primary and secondary outcomes.

We will not utilize a trial steering committee for this study.

Composition of the data monitoring committee, its role and reporting structure {21a}

Data will be monitored throughout the study by the university that has access to the identifiable data. A data monitoring committee will not be put in place, given the intervention is minimal risk and is occurring in the context of ongoing child welfare and high-risk prevention services.

Adverse event reporting and harms {22}

We anticipate minimal risks to participants in this study. If an adverse event occurs after the participant provides verbal consent to the study but prior to beginning the intervention or if it occurs after a participant is discontinued from the study, it will not be reported. If an adverse event occurs after a consenting participant begins the intervention, it will be reported to the IRBs at both institutions.

Plans for communicating important protocol amendments to relevant parties (e.g., trial participants, ethical committees) {25}

Important protocol changes to date (e.g., expanding eligibility criteria) were approved by all investigators, the study funder, and both IRBs and are described below. Any future protocol amendments, if needed, will be approved by all study investigators and IRBs. If an amendment is needed that changes the aims and scope of the study, the study funder will need to approve the proposed changes, in addition to study investigators and IRBs.

Changes to the initial protocol made and approved to date

Due to unforeseen challenges in recruiting participants for the research study, we have implemented the following changes to our methods. The changes detailed below and the reasons for the protocol changes are presented below and are reflected in this manuscript. Any subsequent amendments to this protocol, if necessary, will be approved by all PIs and submitted to the IRB at both institutions for approval.

Parent participants

We made six changes to our protocol for parent participants. First, we initially proposed that we would recruit mothers only. However, we expanded the criteria to include all parents and caregivers of young children engaging in the SafeCare program, which includes biological mothers, biological fathers, legal custodians, and grandparents. Second, we removed the criterion that a family must start SafeCare or SFHSC with the Safety or Health module—now they can start in any module. We made this change because some SafeCare implementations must start with a SafeCare module that is mandated by the state based on the family’s needs, which led to unnecessary exclusion for these families. Third, we increased the compensation for each family survey from US $30 to US $50 due to inflation and the total amount of time it took to complete the surveys, which was longer than originally projected. Fourth, we expanded the age range for children in the home in one state, such that parents of children ages 0 to 9 years in this state are eligible to participate, which complies with family requirements for SafeCare implementations in this state. Fifth, we expanded the criteria to include families even if the child does not live in the home. Families receiving SafeCare may be involved with child protection, and as such, their child may not be currently living with their biological parents even while the parent is engaged in the SafeCare program. Sixth, we expanded eligibility to also include Spanish-speaking families after receiving feedback from providers that SFHSC would be relevant for the Spanish-speaking families they serve.

Provider participants

We made five changes related to our protocol for provider participants. First, we initially proposed to recruit providers and families from agencies in Oklahoma and Iowa due to high adult smoking rates and successful and established state-wide SafeCare implementations. We chose to expand partner sites in the following states: Arkansas, Arizona, Colorado, Montana, Pennsylvania, and Texas due to recruitment challenges and saturation within agencies. Second, we expanded our study setting from providers working exclusively with CPS-involved families only to also include providers working with at-risk families. Given much research has shown little distinct differences between families experiencing cumulative risk, irrelevant of CPS involvement, the inclusion criteria were expanded to allow for greater opportunities in recruitment. We increased provider compensation for (a) completing one session preparation call (providers in both conditions) and four coaching calls for the first two families a provider serves (SFHSC condition only) from US $0 to US $100 (US $20 per task) and (b) completing six family Qualtrics surveys (for each session per family) from US $50 to US $60 due to unanticipated time and burden of these study requirements. Third, we expanded eligibility criteria to include both certified SafeCare providers and providers with certification in progress to expand our recruitment opportunities. Fourth, because providers in one state are unable to upload audio recordings of sessions to complete coach-rated fidelity using standard NSTRC implementation methods, we developed self-rated fidelity assessments to still collect fidelity data from those providers. We chose to expand the collection of self-rated fidelity to all providers for potential exploratory analyses. Fifth, due to slower-than-anticipated recruitment, we added refresher training for providers in both conditions to review study procedures and materials during the study period. After providers enrolled in the study, there often was a delay between the initial workshop and the providers serving their first eligible research family. Thus, we chose to add additional opportunities for providers for them to review study procedures. Providers can participate in one refresher training per year and are compensated US $60 for attending these webinars.

Dissemination plans {31a}

When available, the study findings will be disseminated at professional research conferences, through peer-reviewed manuscripts, and via reports and presentations to NSTRC agencies and their providers.

Discussion

No evidence-based programs exist that jointly target SHS exposure and maltreatment risk, two adverse exposures that individually and collectively have severe negative impacts on child health and health throughout the lifespan. This study will be the first to document the outcomes of a multi-component intervention to address cumulative risk factors that impact cancer risk among children whose parents are at risk or involved in child-protective services. Integrating an evidence-based intervention that targets SHS exposure in the home with a broadly disseminated CM prevention intervention may be a way to help reduce the negative effects of childhood exposure to maltreatment and the compounded effects of SHS in the home and CM. The implementation context of the CM intervention in the US could allow for broad and sustainable dissemination of this multi-component intervention to improve child health and health throughout the lifespan.

Innovation

There are five main innovations for this research. First, given that the SFH intervention was developed as a stand-alone intervention, the current study is innovative in that we are adapting the delivery of the SFH intervention into a broadly disseminated parenting intervention. If effective, this approach could significantly enhance the reach of the SFH intervention. SafeCare reaches over 8000 families annually, and it is just one of several broadly disseminated evidence-based parenting interventions in the USA. If effective, SFHSC could serve as a model demonstrating that SFH can be integrated into widely disseminated programs that serve families where secondhand smoke is common.

Second, this is the first study to promote a smoke-free home intervention with CPS-involved families and families at risk of being involved with CPS. These families tend to have lower resources, higher stress, and higher smoking rates than families not involved or at risk of being involved with CPS [2, 4, 43]; as such, implementing interventions to reduce secondhand smoke exposure may be one strategy to reduce this health disparity.

Third, the importance of integrating evidence-based programs that target multiple outcomes has become increasingly discussed in the scientific literature in recent years [26]. Integrated interventions targeting multiple health outcomes related to cancer are also a recent priority strategy of the National Cancer Institute to achieve Cancer Moonshot 2047 goals and reduce cancer deaths [25]. Systematic braiding is a structured approach to developing a blended intervention that addresses two or more health outcomes and has been developed and tested by parenting researchers [27, 28]. If effective, this study offers further validation and an application of systematic braiding, which can inform future efforts and work toward achieving Cancer Moonshot goals.

The fourth innovation advances science into the understanding of how program integration impacts target outcomes and program implementation costs within an implementation science framework. Our secondary outcome of this study is to explore whether the braided intervention has the same or a weaker effect on parenting outcomes. Further, we will examine differences in delivery time and costs to determine if the implementation of a braided intervention could occur without a significant increase in overall program resources and costs. Lastly, the SFH intervention has demonstrated the sustainability of a full home smoking ban for up to 6 months [36–38]. The current study will explore the sustainability of a smoke-free home for up to 1 year.

Limitations

The current study is a randomized trial, the gold standard in intervention research and implementation science. However, as with all empirical research, there are limitations to this study. First, the survey data are self-reported and may reflect biased responses, which may be particularly relevant for families who might be worried about a CPS report (e.g., smoking in the home or around their child, parent stress, parenting behavior, child injuries, child health); however, we will be using air nicotine monitors to validate the self-report data on smoking in the home. Second, the time diaries for the providers may introduce recall bias. To address this, we ask the providers to complete these within a week of seeing their family and provide paper copies to record their time spent on certain program tasks. Third, only providers and families in eight US states are included in this study. While these states are geographically and socio-demographically diverse, the limited number of states included could limit the generalizability of CPS-involved and at-risk families in the USA.

Trial status

The protocol presented in this manuscript was Protocol Version 2, March 15, 2024. Recruitment for the trial commenced in April 2022, and we have recruited nearly 8% of the total participants required for this study to date. We anticipate that recruitment will be completed by December 2025.

Abbreviations

SFH

Smoke-Free Homes: Some Things are Better Outside

CM

Child maltreatment

SHS

Secondhand smoke

SFHSC

Smoke-Free Home SafeCare

CPS

Child-protective services

IRB

Institutional Review Board

NSTRC

National SafeCare Training and Research Center

SES

Socio-economic status

Authors’ contributions {31b}

EWPM supported the proposal development, led the writing of the protocol paper, and supported in the trial operations. SSB is a multiple principal investigator; she co-conceived the study, led the proposal and protocol development, and oversaw the trial operations. MK is a multiple principal investigator; she co-conceived the study, led the proposal development, and supported in the trial operations. RH is the lead trial methodologist and contributed to the study design and development of the proposal. DW, CS, JH, are co-investigators and contributed to the study design and the development of the proposal. KK contributed to the study operations. All authors read and approved the final manuscript.

Funding {4}

This study was funded by the National Cancer Institute 1R01CA248551-01A1. The funder did not play a role in study design, data collection, analyses, or in the writing of this manuscript.

Availability of data and materials {29}

Georgia State University and Emory University will have access to the final trial dataset; however, Emory University will only have access to de-identified data.

Declarations

Ethics approval and consent to participate {24}

We obtained ethical approval from the Institutional Review Boards at Georgia State University and Emory University to conduct this research (H21543).

Consent for publication {32}

A model consent form will be made available upon request.

Competing interests {28}

The authors declare that they have no competing interests.