Table 1. Description of trials of health behaviour change interventions: Smoking cessation.

Study	Study Design, Country, Device, and Media	Participants	Aims	Intervention	Comparator
Abroms 2014 [21]	Parallel group RCT; Country: USA; Device: Mobile telephone; Media: SMS	503 adult smokers aged ≥18 y. Mean age: Control 35.5 (SD 10.6); Intervention: 35.9 (10.7). Females: Control 62.8%; Intervention 68.7%. Study advertisements appeared to individual who google searched keywords relating to quitting smoking. Eligibility criteria included having an interest in quitting smoking in the next month.	To evaluate the effect of Text2Quit intervention on biochemically confirmed repeated point prevalence smoking abstinence.	Participants received a facilitated text messaging program designed smoking consisting of automated bidirectional text messages. Text messages were timed around the user’s quit date and provided advice on quitting smoking and were based on social cognitive theory. Messages were interactive and prompted user to track smoking, report on cravings and provide smoking status. Messages were tailored around several factors including first name, quit date, top three reasons for quitting, money saved by quitting, and use of quit-smoking medications. The first three months of intervention offered both outgoing messages and on-demand help through the use of key words. After the outgoing messages stopped, participants could still text for help using keywords. Outgoing messages peaked just prior and following the quit date. SMS messages were supplemented by a personalized web portal (text2quit.com) and emails. Duration: 6 months User involvement in development: not stated.	Participants randomized to the control group initially received a web link to Smokefree.gov, a leading website with quitting smoking information run by the NCI. During the study, Smokefree.gov launched its own texting program, SmokefreeTXT. The control group material was changed to avoid contamination of the control group with a similar texting program. At this point, 135 (26.8%) participants had been recruited into the study, 66 of whom were in the control group. Future control group participants were offered a guidebook on quitting smoking developed by the NCI containing similar advice and information as Smokefree.gov. The control group also received study-related reminder texts via SMS, particularly in the 2 weeks prior to each follow-up survey.
Borland 2013 [22]	Parallel group RCT Country: Australia; Device: Mobile telephone; Media: SMS	3530 adult smokers and recent quitters (quit within past 2 weeks) aged ≥ 18 y. Mean age 42.1 y. Females 60% Participants recruited from callers to smoking quitlines (n = 1335), and from an internet panel survey (n = 2195) composed of a mixture of known smokers and those of unknown smoking status. Participants recruited from quitlines were more highly motivated to quit.	To test the population impact of offering automated smoking cessation interventions via the internet and/or by mobile telephone.	Four intervention groups: (1) received a personalised, automated tailored cessation program based on cognitive-behavioural principles that generates 2–4 page letters of advice with suggestions about strategy; (2) received a stream of SMS that mix snippets of advice on strategy and motivation; (3) participants could use either or both parts of interventions 1 and 2 which were offered as a package; (4) participants explicitly offered either or both interventions 1 and 2, with the person encouraged to make an upfront choice although they could subsequently change their minds, and take up whatever aspects they wanted. Duration: 7 months User involvement in development: not stated.	Participants received brief information on web- and telephone-based assistance available in Australia.
Buller 2014 [23]	Parallel group RCT Country: USA; Device: Mobile telephone; Media: Application software, SMS	102 adult smokers aged ≥ 18 y. Mean age: Control 24.3 y; Intervention 25.5y. Females: Control 57%; Intervention 45%. Participants recruited through online advertising systems–eligibility criteria included interest in quitting.	To explore the usability, effectiveness and comparability to a SMS programme of a mobile application to support smoking cessation.	Participants were given a smartphone with unlimited phone, SMS and data service on which to use the mobile application. Participants received short messages in an email-like inbox and audio phase-transition messages were delivered to enhance comprehension. Participants could create lists; listen to audio testimonials and read support documents. The short messages directed participants to quitting tools and encouraged them to use the study Website to view additional resources. Duration: 12 wk. User involvement in development: “Two rounds of formative testing of REQ-Mobile with smokers 18–30 years old (59% female) confirmed usability. In Round 1 (n = 17), 76–100% of smokers completed 11 tasks. After REQ-Mobile was revised, 90% of smokers in Round 2 (n = 10) completed seven of nine tasks, and completion times decreased. In both rounds, smokers rated REQ-Mobile favourably.”	Participants were given a smartphone with unlimited phone, text and data service on which they received SMS grounded in social cognitive theory and a modified version of the Transtheoretical model.
Chan 2015 [24]	Parallel group RCT; Country: Hong Kong; Device: Mobile phone; Media: SMS	1003 adult daily smokers aged ≥18 y. Age: % 18–39, Control 35.8%, SMS intervention 39.1%. Females: control 16.1%, intervention 19.4%. Participants recruited from ‘Quit to Win Contest’ which aimed to attract and encourage smokers to quit by rewarding them with financial incentives if they had achieved smoking abstinence at a predefined follow-up. >85% of participants reported intention to quit within the next 30 days at baseline.	To examine the effectiveness of brief interventions (3 arms—one delivered by SMS, one delivered by nurse-led telephone counselling, and control) for smokers who joined the Hong Kong Quit to Win Contest to quit smoking.	The SMS group received eight mobile telephone text messages which were constructed with reference to an eight-page smoking cessation booklet received. The content of the messages included (i) warning about the health hazards of smoking, (ii) benefits of quitting, (iii) contact information of publicly available smoking cessation services, (iv) strategies of quitting and (v) encouragement and reminder of follow-up. Duration: 12 months User involvement in development: not stated	The CONTROL group did not receive any intervention above other than the self-help booklet and the contact information of the smoking cessation services at the enrolment.
Free 2011 [25]	Parallel group RCT; Country: UK; Device: Mobile telephone; Media: SMS	5800 adult smokers aged ≥ 16 y. Mean age: 36.8 5 y (SD 11.05). Female 45% Recruited through advertising. Eligibility criteria included willingness to make an attempt to quit smoking in the next month.	To evaluate the effect of mobile phone-based SMS support on the point prevalence of smoking at 6 months	Participants received daily SMS before the quit date, then 5 SMS per day for 4 wk after the quit date. Between 4 and 26 wk participants received 3 SMS per week. Message content was tailored to participant interests and concerns about quitting smoking. Participants were offered a quit buddy contactable by mobile phone and an SMS craving helpline with an instant SMS response. The SMS system was fully automated. Duration: 26 wk. User involvement in development: modifications made to intervention based on feedback from 62 participants.	Participants received fortnightly simple, short, generic SMS.
Free 2009 [26]	Parallel group RCT; Country: UK; Device: Mobile telephone; Media: SMS	200 adult smokers aged ≥ 16 y. Mean age: 36 y (SD 9.0). Female 38% Recruited through advertising. Eligibility criteria included having interest in quitting.	To evaluate the effect of mobile phone-based SMS support on the point prevalence of smoking at 4 wk.	Participants received daily SMS before the quit date, then 5 SMS per day for 4 wk after the quit date. Between 4 and 26 wk participants received 3 SMS per week. Message content was tailored to participant interests and concerns about quitting smoking. Participants were offered a quit buddy contactable by mobile phone and an SMS craving helpline with an instant SMS response. The SMS system was fully automated. Duration: 26 wk. User involvement in development: as above (Free 2011) modifications made to intervention based on feedback from 62 participants.	Participants received fortnightly simple, short, generic SMS.
Gritz 2013 [27]	Parallel group RCT Country: USA; Device: Mobile telephone; Media: Voice calls	474 adult smokers ≥ 18 y. Mean age: Control 45.7 y (SD 7.8); Intervention 43.9 y (SD 8.3). Females 30% Recruited from HIV clinic. Eligibility criteria included willingness to set a quit date within 7 days.	Assess the efficacy of a mobile telephone smoking cessation counselling intervention aimed at a multi-ethnic, economically disadvantaged HIV-positive population.	Participants received usual care (written smoking cessation materials and instructions on how to obtain nicotine patches from the clinic) plus a pre-paid mobile phone on which they received counselling and could access a supportive hotline. Duration: 12 months User involvement in development: not stated	Participants received usual care: written smoking cessation materials and instructions on how to obtain nicotine patches from the clinic.
Haug 2009 [28]	Parallel group RCT Country: Germany; Device: Mobile telephone; Media: SMS	174 adult smokers. Mean age: Control 25.4 y (SD 4.9); Intervention 1 (1 SMS) 25.2 y (SD 4.8); Intervention 2 (3 SMS) 24.3 y (SD 3.8). Females: Control 63%; Intervention 1 56%; Intervention 2 52%. Recruited university students who reported daily smoking.	Investigate the feasibility and acceptability of interactive mobile phone text messaging to support smoking cessation and the impact of different SMS frequency (intensity).	Participants received a weekly SMS with a question to assess their stage of change (transtheoretical model). Two intervention groups then received either 1 (1 SMS group) or 3 (3 SMS group) tailored feedback SMS per week. Participants attempting to quit had access to an SMS craving helpline which provided up to 60 tailored SMS responses. The SMS-COACH programme was fully automated. Duration: 14 wk. User involvement in development: not stated.	Participants received only the weekly SMS question to assess their stage of change (transtheoretical model).
McDaniel 2015 [29]	Parallel group RCT; Country: USA; Device: mobile phone; Media: IVR	1785 smokers aged ≥18 y recruited from employer and health plan quitline programmes. Mean age: Control 43.3 (SD 12.2); Low intensity IVR 44.0 (SD 11.5); High intensity IVR 43.0 (SD 12.0). Females: control 54.2%, low intensity IVR 54.1%, high intensity IVR 54.2%. Participants were recruited from the Quit For Life programme and must had achieved abstinence for at least 24 hours after their quit date, prior to randomisation.	To test adding an interactive voice response (IVR)-supported protocol to standard quitline treatment to prevent relapse among recently quit smokers.	In the two Technology Enhanced Quitline (TEQ) groups, participants were contacted for relapse risk assessments through automated IVR calls over their first 8 weeks post-quit. Two intensities of IVR monitoring were examined. TEQ-10 participants were contacted twice weekly for the first 2 weeks, then weekly for 6 weeks. TEQ-20 participants were contacted daily for the first 2 weeks, then weekly for 6 weeks. An IVR service contractor programmed and delivered the risk assessments (approximately 5 min), which included questions to identify relapse risk on five factors: lapses, cravings, negative affect, self-efficacy and motivation to remain quit. An algorithm was used to flag participants as ‘at risk’ if they answered any of the screening questions over an established threshold. Participants who exceeded the threshold were then transferred directly to a Quit Coach for a brief intervention (approximately 15 min) specifically addressing the risk factor(s) that triggered their transfer. Duration: 12 months User involvement in development: not stated.	The control group received the standard quitline without IVR monitoring.
Peng 2013 [30]	Parallel group RCT Country: Taiwan; Device: Mobile telephone; Media: Voice calls	116 student smokers in Taiwan universities aged ≥ 16 y. Mean age 19.64 (SD 1.337). Females 7.8% Recruited student smokers.	To evaluate the effectiveness of a web phone intervention that delivered phone calls and motivational and educational recorded messages to change smoking behaviour in university student smokers.	Two intervention groups: (1) participants received a phone call at 1 and 9 measuring stage of change, total number of non-smoking days if applicable, self-efficacy and decision balance and also 2 assessment calls per week for 3 wks measuring only stage of change and total number of non-smoking days if applicable; (2) participants received a phone call at 1 and 9 measuring stage of change, self-efficacy and decision balance and also 2 calls per week for 3 wks measuring stage of change and the total number of non-smoking days if applicable. Participants then received 5 to 8 reminder voice messages tailed to address the participant’s stage of change. Duration: 9 wk. User involvement in development: not stated.	Participants received a phone call at 1 and 9 wks for the purpose of measuring stage of change, self-efficacy and decision balance (no intervention given).
Pollak 2013 [31]	Parallel group RCT Country: USA; Device: Mobile telephone; Media: Voice calls	31 adult, pregnant smokers in their second trimester aged ≥ 18 y. Mean age: Control 27 y (SD 6); Intervention 29 y (SD 6). Eligibility criteria included willingness to try and quit smoking.	To assess feasibility of a SMS-based smoking cessation intervention for pregnant smokers, to determine the acceptability of a SMS-based SGR plus support messages intervention, and to obtain preliminary efficacy data for SMS-based SGR to promote cessation during pregnancy.	Participants received up to 5 SMS per day for 5 wks. Participants received “alert messages” at scheduled times that instructed participants to smoke and were designed to help them gradually cut down to 0 cigarettes by the end of the fourth week. If participants smoked at an unscheduled time it was requested that they message back “s” so the next alert would correspond with the scheduled interval. If participants messaged 3 times “off schedule,” the alert messages were stopped and resumed the next day. If this pattern continued for more than a day, the participant was called and asked if the schedule needed adjustment. Participants were asked to sign a contract stating they will not smoke more cigarettes during the study than they did before they entered the study. Participants were informed that if they responded to 80% of the alert texts, they would be entered into a $25 gift card raffle. Duration: 6 wk. User involvement in development: not stated prior to this. However, this was a pilot study which was also collecting feedback on intervention from users.	Participants were asked to choose a quit date within 2–3 wks post randomisation and then sent an SMS stating that quit date. Participants received up to 5 SMS per day for 5 wks. Each week, there was a new “theme” for a subset of the messages, such as reasons for quitting, getting ready for the quit date, partner smoking, and handling slips.
Rodgers 2005 [32]	Parallel group RCT Country: New Zealand; Device: Mobile telephone; Media: SMS	1705 adult smokers aged ≥ 16 y. Mean age 25 y. Female 58%. Eligibility criteria included interest in quitting smoking within the next month.	Assess the efficacy of SMS for supporting smoking cessation.	Participants set a quit date and received 5 SMS per day for 1 wk before and 4 wk after the quit date. Between 4 wk after the quit date and the end of the study (26 wk) participants received 3 messages per week. SMS contained information or advice on quitting smoking and some distractions (e.g. sports news, quizzes. and polls/surveys). Participants received 1 months of free outgoing text messages after their quit date. Participants were offered a quit buddy (another study participant) contactable by mobile telephone. Participants had access to an SMS craving helpline to receive an instant reply with tips on cravings. The SMS system was fully automated and a computer algorithm was used to match the SMS sent to the participant characteristics. Duration: 26 wk. User involvement in development: “The messages were developed by a multidisciplinary team including young adults, Maori health researchers, and experts in adolescent health, nutrition, cognitive behavioural therapy, and smoking cessation.”	Participants only received one text message every 2 wk, thanking them for being in the study, providing study centre contact details, informing them that those who completed follow-up would be rewarded with a free month of text messaging (whether they quit or not), and reminding them of the time until their free month at the end of follow-up.
Shi 2013 [33]	Cluster RCT Country: China; Device: Mobile telephone; Media: SMS, web links via SMS	179 adolescent smokers aged ≥ 16 y. Mean age: Control 16.9 y (SD 0.7); Intervention 17.6y (SD 1.1). Females: Control 15%; Intervention 14%. Recruited adolescents who reported smoking at least 1 cigarette per week for at least 12 weeks.	To test whether a mobile telephone SMS messaging based smoking cessation intervention package could increase the self-reported smoking abstinence and reduce daily cigarette consumption in adolescent smokers from 6 vocational schools in metropolitan Shanghai.	Participants from three intervention schools received interactive smoking cessation intervention delivered via mobile telephone SMS messaging. SMS messages were sent at a time that was common to smoking in the baseline survey every day. A stage-matched protocol was used to provide tailored assistance messages that matched participants’ stage of readiness to quit. Participants were encouraged to send SMS messages to investigators to obtain counselling and clear up confusion. Participants were also given online support by sending web links to their mobile telephones and encouraged to use online chatting relating to their cessation experience. Participants were asked about their smoking status every week and provided feedback depending on whether they were improving or relapsing via SMS. Duration: 12 wk. User involvement in development: “We conducted focus group discussions with adolescent smokers to identify their needs and attitudes towards the intervention.”	Participants received a printed self-help pamphlet based on focus group discussions with adolescent smokers and organised according to the Transtheoretical Model and stages of change.
Skov-Ettrup 2014 [34]	Parallel group RCT Country: Denmark; Device: Mobile telephone; Media: SMS	1619 adolescent and young adult smokers aged ≥ 15 y. Mean age: Control 19.5 (SD 3.2); Intervention 19.4 (SD 3.1). Females: Control 58.3%; Intervention 60.3%. Recruited participants from smokers who had signed up to Xhale.dk (an internet- and text message-based smoking cessation service. Eligibility criteria included having set a quit date between 14th February 2007 and 1st August 2009.	To test whether tailored SMS messages delivered at a higher frequency result in higher abstinence among users of an internet-based smoking cessation programme. Also to test whether baseline self-efficacy and beliefs about smoking were predictors of smoking cessation in adolescents and young adults.	Participants received a weekly SMS message up to 4 wks before their quit date, and a daily message 1–3 days before the quit date. Then they received 2 tailored SMS messages per day during a period of 4 wks. For the following 4 wks, the frequency of SMS messages declined to 4–5 SMS messages per wk. The system generated 3 types of tailored messages based on three different tailoring parameters: self-efficacy, beliefs about smoking and themes chosen by the user. Information about these parameters was obtained from the baseline questionnaire. The tailoring was a combination of content matching, descriptive and evaluative feedback. Duration: 12 months User involvement in development: not stated.	Participants received SMS messages to their mobile telephones once daily for 5 wks beginning 5 days before the chosen quit date. Weekly messages were sent for the following 3 wks. All participants received the same message on each day during their attempt counted from their preferred quit date. Messages were personalized by including the participant’s username. Otherwise they were untailored.
Vidrine 2006 [35]	Parallel group RCT Country: USA; Device: Mobile telephone; Media: Voice calls	95 HIV positive adult smokers aged ≥ 18 y. Mean age: Control 43.1 y (SD 8.1); Intervention 42.6 y (SD 8.2). Females: Control 17%; Intervention 27.1%. Recruited from HIV care centre. Eligibility criteria included willingness to set a quit date in the next 7 days.	Assess the efficacy of a mobile telephone smoking cessation counselling intervention aimed at a multiethnic, economically disadvantaged HIV-positive population.	Participants set a quit date with their physician and received a personalized smoking cessation plan and a general self-help materials. Participants were given a prepaid mobile telephone and received 8 phone-counselling sessions during 2 months. The counselling sessions were more often close to the quit date. Participants could also call the hotline when they needed additional smoking cessation support. The phone counselling and support was provided by a study researcher. Duration: 3 months User involvement in development: not stated	Participants received usual care: they set a quit date with their physician who offered a 10-wk supply of nicotine replacement therapy and received the personalized smoking cessation plan and a general self-help materials.
Whittaker 2011 [36]	Parallel group RCT Country: New Zealand; Device: Mobile telephone; Media: SMS, Video message	226 young adult smokers aged ≥ 16 y. Mean age 27 y (SD 8.7). Females 47% Recruited through advertising. Eligibility criteria included ‘wanting to quit’.	To determine whether a video-based smoking cessation intervention delivered via mobile telephone was effective at increasing smoking cessation rates.	Participants nominated a quit day between 1 and 3 wks from randomisation and 2 time periods during which they wished to receive SMS. Participants were directed to an online brief description and photograph of the 6 role models and asked to select a role model from whom they would receive messages. The video messages were filmed as video diaries during a quit attempt, with the role models discussing issues they had found difficult and the techniques and coping strategies they used to remain smoke-free. The intervention was arranged into a chronological schedule of mobile phone messages that included the role model videos, SMS, and other video messages (animations about reasons to stop smoking; and “truth” campaign mass media advertisements supplied by the American Centres for Disease Control and Prevention). Participants could review video messages they had been sent (and rate them if desired), change their selected time periods, and change selected role model using a website. Participants could also ask for extra support messages on demand by texting keywords to the study shortcode. Duration: 6 months User involvement in development: 180 young people participated in the consultation stage involving focus groups, an online survey, content pre-testing, selection of role models, and a pilot study.	Participants nominated a quit day between 1 and 3 wks from randomisation and 2 time periods during which they wished to receive SMS messages. Participants received one video message every 2 weeks with general health messages and reminders about the study.
Ybarra 2012 [20]	Parallel group RCT Country: Turkey; Device: Mobile telephone; Media: SMS	151 adult smokers aged ≥ 18 y. Mean age: Control 35.6 (SD 10.3); Intervention 36.1 (SD 9.5). Females: Control 32%; Intervention 46.1%. Recruited though in-person outreach and advertisements. Eligibility criteria included ‘seriously thinking about quitting in the next 15 days’.	To provide estimates of effect size to better inform a power analysis for a larger trial with a small-scale trial looking at the efficacy of a SMS-based smoking cessation programme in a Middle Eastern setting.	Participants received daily SMS for 6 wks. Participants generally received 5 SMS per day in the pre-quit phase and then received more SMS as the quit day approached. The highest number of messages was sent on the quit day and the day after; and then the number of messages began to taper down until the last week where participants were sent 1 SMS per day. Duration: 3 months User involvement in development: not stated. However this was a pilot trial and included data collection on intervention acceptability and recommendations for improvements.	Participants were given general quitting information in a 7 page brochure.
Ybarra 2013 [37]	Parallel group RCT Country: USA; Device: Mobile telephone; Media: SMS	164 young adult smokers aged ≥ 18 y. Mean age: Control 21.6 (SD 2.1); Intervention 21.6 (SD 2.1). Females: Control 44.4%; Intervention 43.6%. Recruited through advertisements. Eligibility criteria included seriously thinking about quitting smoking in the next 30 days.	To develop and pilot test a SMS-based smoking cessation programme for young adults.	Smoking cessation group participants were exposed to a 6-week smoking cessation program with content that was tailored to where participants were in the quitting process (i.e., Day 1 to 14 or the Pre-Quit phase, Day 15 to 21 or the Early Quit phase, or Day 22 to 42 or the Late Quit phase). Participants received SMS at Post-Quit Day 2 and 7 that asked their smoking status. If participants reported smoking, they were sent relapse SMS that focused on helping them recommit to quitting. Frequency of messages varied according to quitting stage. Intervention group participants had access to (a) Another person in the program that a participant was assigned to so they could SMS one another for support anonymously during the programme; (b) Immediate, on-demand SMS aimed at helping the participant through a craving. A project Web site provided additional resources. Duration: 3 months User involvement in development: Stop My Smoking USA intervention was refined for young adult smokers in US. Involved needs assessments focus groups (n = 35), content advisory team (n = 10), and tests of technological feasibility (n = 40) with young people aged 18–25.	Participants in the sleep/activity group received text messages at the same rate as the smoking cessation group in order to match the level of attention that the smoking cessation group was receiving; however, content of the text messages was aimed at improving participants’ sleep and physical activity habits within the context of how it would help the participant quit smoking

RCT, randomized controlled trial; SD, standard deviation; SMS, short message service; SCA, smoking cessation adviser; SGR, scheduled gradual reduction.