Expanding population-level interventions to help more low-income smokers quit: Study protocol for a randomized controlled trial

Abstract

Background:

Low-income Americans have higher rates of smoking and a greater burden of smoking-related disease. In the United States, smokers in every state can access evidence-based telephone counseling through free tobacco quitlines. However, quitlines target smokers who are ready to quit in the next 30 days, which can exclude many low-income smokers. A smoke-free homes intervention may help engage smokers in tobacco control services who are not yet ready to quit. Previous research in low-income populations suggests that receiving a smoke-free homes intervention is associated with higher quit rates. This study tests whether, at a population level, expanding on quitlines to include a smoke-free homes intervention for smokers not ready to quit could engage more low-income smokers and increase long-term cessation rates.

Methods:

In a Hybrid Type 2 design, participants are recruited from 211 helplines in 9 states and randomly assigned to standard quitline or quitline plus smoke-free homes intervention arms. Participants in both arms are initially offered quitline services. In the quitline plus smoke-free homes condition, participants who decline the quitline are then offered a smoke-free homes intervention. Participants complete a baseline and follow-up surveys at 3 and 6 months. Those who have not yet quit at the 3-month follow-up are re-offered the interventions, which differ by study arm. The primary study outcome is self-reported 7-day point prevalence abstinence from smoking at 6-month follow-up.

Conclusion:

This real-world cessation trial involving 9 state tobacco quitlines will help inform whether offering smoke-free homes as an alternative intervention could engage more low-income smokers with evidence-based interventions and increase overall cessation rates.

This study has been registered at ClinicalTrials.gov (Study Identifier: NCT04311983).

1. Introduction

Although overall smoking rates among U.S. adults have declined for the last decade and reached a low of 13% in 2020, rates remain higher among particular subgroups, including those with less than a high school education (22%) and with household income <$35,000 per year (20%) [1]. Compared to other smokers, low-income smokers begin smoking at a younger age, are more likely to live and work with other smokers, have greater nicotine dependence, lower self-efficacy for quitting, lower readiness to quit, are less likely to use evidence-based quitting methods, and succeed less often when trying to quit [2–8]. They are also more likely to be diagnosed with cancer and have higher mortality rates, partly due to the illnesses being diagnosed at later stages [9,10]. Cancer is the largest contributor to a growing gap in U.S. life expectancy by education [11], and smoking has a significant independent effect on cancer disparities by level of education [12].

One of the challenges in providing cessation services to low-income populations is that typically only 20–30% of low-income smokers are ready to quit at any given time [13–15] compared to two-thirds of smokers in the general population [16]. State tobacco quitlines are an evidence-based, population-level cessation intervention; however quitlines, constrained by state budgets, typically provide their full range of services to those who are ready to quit in the next 30 days. Smoke-free homes interventions could help smokers by offering an intermediate step toward cessation for those not yet ready to quit. Creating a smoke-free home not only reduces the secondhand smoke (SHS) exposure of other people in the home [17], but helps change the smoker’s environment, which can increase the odds of successful quitting [18].

The Smoke-Free Homes: Some Things are Better Outside (SFH) intervention provides support for making a rule banning all smoking inside the home [19,20]. Although no studies have made direct comparisons, prior research has shown that low-income smokers tend to have low confidence in their ability to quit [15,21–26], whereas confidence levels in creating a smoke-free home tend to be relatively high [27]. Thus, creating a smoke-free home may be viewed by smokers as easier to accomplish than quitting [28–30]. Prior research indicates that a majority of participants will engage in the behavioral tasks of the intervention (e.g, putting up stickers, signing a pledge card) [31] and are more likely than a control group to implement a home smoking ban [19]. With regard to smoking cessation, establishing a smoke-free home is also associated with more quit attempts, longer durations of quit attempts and success in quitting [18,32–35]. In one study, participants with no prior quit attempts were more likely to make a quit attempt after creating a smoke-free home compared to participants who did not make a smoke-free home [36]. Genuine “treatment effects” also occur, such as reducing exposure to smoking and other smokers, making it less convenient to smoke at home, and disrupting smoking patterns and cues [18,37].

1.1. Study objectives

This protocol describes a study in which the primary aim is to test whether offering the SFH intervention for daily smokers not yet ready to quit will increase self-reported quit rates compared to offering the standard quitline alone. The primary outcome is self-reported 7-day point-prevalence abstinence at 6-month follow-up. We will also examine secondary outcomes including self-reported 30-day point-prevalence abstinence, 24 h quit attempts and home-smoking rules at 3- and 6-month follow-up, as well as acceptance vs. decline of the offer of intervention(s). We will evaluate the costs and benefits of implementing SFH programming using economic evaluation methods.

2. Methods

2.1. Study population

Participants are recruited through 211 in 9 states starting June 1, 2020. 211 is a nationally available telephone helpline that refers callers to organizations in their community, mostly for assistance with unmet social needs, such as rent, food, and utilities. At the time of submission of this manuscript, baseline enrollment is nearly complete. After a 211 specialist delivers standard service, they ask callers if they are daily smokers (yes/no) and if they allow smoking anywhere inside their home at any time (yes/no). The 211 information specialists are knowledgeable about additional eligibility criteria, such as English-language proficiency, in the event that callers have questions, but rely on the study team to complete all assessments for study eligibility. 211 callers who are daily smokers and do not have a home smoking ban are asked if they are interested in participating in a study for smokers. If interested, the caller’s name and phone number are shared with the study team.

2.2. Study design and procedures

We are using a Hybrid Type 2 randomized trial design [38] to compare two study arms: Arm 1, in which participants are offered standard tobacco quitline services only, and Arm 2, in which participants are first offered standard quitline services, but if the quitline offer is declined, are then offered a SFH intervention (see “Interventions” below). Hybrid designs are used to answer research questions about effectiveness and implementation simultaneously [38,39]. In this Hybrid Type 2 design, the primary aim is to determine intervention effectiveness (effects on cessation, quit attempts, smoking reduction) while secondary aims determine feasibility of an implementation strategy (effects on acceptance of intervention offer(s), actually receiving the intervention(s), and cost-effectiveness and cost-benefit analysis of the SFH intervention) [40].

Upon receipt of the contact information, members of the study team begin contacting potential participants as soon as possible to assess additional eligibility criteria, obtain verbal informed consent and administer the baseline survey over the phone. Eligible participants are English-speaking adults, 21 years and older, who smoke daily, have no home smoking ban and are not pregnant. Importantly, the sample is not restricted by readiness to quit, a common requirement in many quitline studies.

Data are collected via telephone interviews administered by trained research staff at baseline, 3-month, and 6-month follow-up. Participants receive a $25 gift card for each completed survey. Research members who make follow-up calls are not involved in any aspects of intervention delivery (including SFH coaching and mailing materials).

After completing the baseline survey, participants are randomly assigned to one of the two study arms in real-time by the survey administration program. Random assignment is stratified by state to account for state-level differences in quitline benefits, tobacco-related policies, and potential seasonal effects on study outcomes (e.g., cold weather reducing SFH rules). It is executed using balanced sets of 20 random numbers, assuring that for every 20 smokers enrolled from any state, 10 go to each study group.

Interviewer scripts for offering interventions are included as supplementary material. In Arm 1, participants are asked if they would like to receive services from their state’s tobacco quitline, and can accept or decline a referral to the quitline. All participants receive the same scripted quitline offer regardless of state. Likewise, in Arm 2, participants are first asked if they would like to receive services from the quitline. However, if they decline, they are then asked if they would like to receive the Smoke-Free Homes program. Business scholars have shown that offering a variety of products or services attracts more customers and increases sales [41], thus it is expected that by offering the SFH intervention, more smokers will stay engaged with a smoking intervention than with the quitline alone. All participants receive the quitline offer first to prioritize standard practice and cessation outcomes and SFH is offered second to assess the value of adding services to standard practice to ultimately engage more people in tobacco control services.

After completing the 3-month follow-up survey, all participants from both arms of the trial who are still smoking are re-offered an intervention. In Arm 1, participants are asked again if they are interested in receiving quitline services. In Arm 2, participants who accepted the quitline at baseline are offered SFH. Those in Arm 2 who accepted SFH at baseline are offered quitline services again. Those in Arm 2 who declined both the quitline and SFH programs at baseline are offered the quitline first, then SFH if they again decline the quitline. Fig. 1 shows offers and choices available.

Fig. 1.

Participant flow through survey completion and randomization to intervention study arm.

2.3. Interventions

Two interventions are available, depending on study arm: state tobacco quitline services and the Smoke-Free Homes program.

State tobacco quitline services:

Telephone counseling for smoking cessation is evidence-based [42,43], recommended in guidelines for clinical and community preventive services [42,44,45], and available on a population level through state tobacco quitlines. Two tobacco quitline providers for the 9 states involved – Optum and Information and Quality Healthcare (IQH) – are partners in the study. Those who accept are directly enrolled using electronic “fax-back” procedures [46], meaning that quitline coaches proactively initiate contact with the participant. Specific quitline services vary by state, but all provide phone counseling from a quit coach which can be client- or counselor-initiated single- or multi-call sessions, often supplemented with nicotine replacement therapy (NRT), and other available services, including web-based services, a mailed print quit guide, or text messages. The full range of services by state is available as a supplemental table. Coaches are trained in behavior change science and motivational interviewing. They help smokers set a quit date in the next 30 days and schedule future counseling sessions, which typically last 10–15 min, spanning 1–3 months around the quit date. Smokers also may contact the quitline outside of scheduled sessions for assistance. Coaches make three attempts to reach a smoker for each scheduled session.

Smoke-Free Homes: Some Things are Better Outside:

Participants who are randomized to Arm 2 and decline quitline services when offered at baseline are offered the SFH intervention. The SFH intervention, described in detail elsewhere, is recommended as part of the National Cancer Institute’s evidence-based programs for cancer prevention and control [19,31,47]. It guides participants though a 5-step process: (1) deciding to create a SFH; (2) talking about it with household members; (3) setting a date for the home to become smoke-free; (4) making the home smoke-free; and (5) keeping the home smoke-free. Progress from one step to the next is facilitated over a 6-week period by three mailings sent to participants’ homes and one telephone counseling call delivered by a trained Smoke-Free Homes coach. SFH coaches in this study are trained research staff; however, previous trials have demonstrated effectiveness of SFH with 211 information specialists as coaches, suggesting broad dissemination is possible [27]. Table 1 summarizes the intervention components, contents and delivery timeline.

Table 1.

Smoke-Free Homes: Some Things are Better Outside intervention components.

Program component	Contents	Timing
Mailing 1	Smoke-Free Homes Toolkit	Week 0 (acceptance of SFH offer)
	• 5-step guide • Reasons to have a smoke-free home worksheet • Truth about Second-hand Smoke factsheet • Pledge card • Stickers • Signs • Window cling
Coaching call	Supplements mailed materials, directs participants through five steps, lasts 10–20 min	Week 2
Mailing 2	• Challenges & Solutions booklet • Photo story • E-cigarette information sheet	Week 4
Mailing 3	• Newsletter • Third-hand Smoke factsheet • Stickers • Window cling	Week 6

2.4. Fidelity monitoring

Audio recordings of SFH coaching calls are collected throughout the study. The first ten calls from each trained coach are evaluated by at least 2 independent reviewers for fidelity to the coaching call protocol and feedback is provided to the coach. If a high level of fidelity is found, e.g., all components of the call are included and the rater(s) determine that rapport, empathy, and active listening occurred, then a random 10% of all future calls from that coach are assessed for fidelity. If high fidelity is not established within the first 10 calls, additional training is provided to that coach, and each call is evaluated until the protocol requirements are consistently met.

2.5. Data collection

Data are collected for telephone-administered surveys at baseline, 3- and 6-month follow-up; from quitline providers; from a SFH intervention tracking database, biochemical verification of self-reported abstinence from smoking, and verification of creating a smoke-free home via air nicotine monitors. Table 2 summarizes the survey measures.

Table 2.

Measures in baseline, 3-month and 6-month follow-up surveys.

MEASURES	Baseline	3 Months	6 Months
Primary Outcome
7 day point-prevalence cessation			x
Secondary Outcomes *
7 day point-prevalence cessation		x
30 day point-prevalence cessation, 24-h quit attempts, Rules about smoking in home		x	x
Acceptance of intervention offer(s)	x	x
Other Outcomes
Ambivalence about smoking, pessimism about quitting, nicotine dependence, readiness to quit	x	x	x
Covariates
Use of quit aids (if not quit at follow-up), depression, interest/confidence in smoke-free home, sleep quality, perceived stress, health-related quality of life	x	x	x
Household composition, housing situation (e.g., type of housing, renting or owning, landlord rules about smoking)	x	x
Interest in quitline services, smoking history, social support, social norms of smoking, social needs, socio-demographics	x
Engagement with SFH strategies and recommendations (e.g., putting up stickers, signing the pledge card), evaluation of intervention (if applicable)		x	x

^*Note. Cost Effectiveness Analysis (CEA) and Cost Benefit Analysis (CBA) results, such as cost per successful quit, are also secondary outcomes. However, the CEA and CBA are conducted using secondary data sources rather than survey items. See section on economic evaluation.

Baseline survey.

Standard measures from the North American Quitline Consortium (NAQC) Minimal Dataset for Intake [48] are used, including: age at smoking initiation; intention to quit smoking in the next 30 days; and the 2-item Heaviness of Smoking Index [49](number of cigarettes smoked per day, minutes to first cigarette after waking). Socio-demographic survey items include age, sex, race, Hispanic ethnicity, annual pre-tax household income, level of education, health insurance status and type, and ZIP code.

Other smoking variables include cessation history (ever, when the last attempt occurred, duration of last attempt), social norms of smoking (whether smoking is allowed at work, number of family and friends who smoke), interest in receiving various services from state tobacco quitlines [50]), confidence in quitting (1–10 scale), past use of NRT (ever used each of seven FDA-approved quit aids), readiness to quit smoking [51,52], ambivalence about smoking (3 items) [53], and pessimism about quitting (5-item subscale from Cessation Fatigue Scale [26]). Ambivalence about smoking has been associated with increased desire to quit [53], while pessimism about quitting has been associated with more perceived difficulty quitting, lower self-efficacy for quitting and less intention to quit [26].

We assess home smoking bans using items from the Center for Disease Control and Prevention’s (CDC) Behavioral Risk Factor Surveillance System (BRFSS) items, which include: rules about smoking in your home (smoking is not allowed in your home at any time/smoking is allowed in some places or at some times in your home/smoking is allowed anywhere inside your home/there are no rules about smoking in your home) [54]. The SFH program specifies that the home-smoking ban should include all smoking, including vaping and marijuana, thus a follow-up question asks for clarification about whether any rule applies to all smoking. Potential covariates, including the number of other smokers, non-smokers and children living in the home, information about the participant’s residence (type of home, owner or renter, property rules if renting, housing satisfaction, options for smoking outside, neighborhood safety, amount of space in the home, and housing quality) [55] are also assessed.

Other survey measures include the likelihood of experiencing various unmet social needs in the next 30 days (e.g., reliable transportation, childcare, food and housing insecurity, physical threats or harm, and having enough money for bills, necessities, unexpected expenses and a $400 emergency expense) and the 12–item Short Form Health Survey (SF-12v2) [56] which is used to measure health-related quality of life. We also record acceptance (yes/no) of each offer (quitline or SFH).

3- and 6-month follow-up surveys.

To assess point prevalence abstinence [57], participants are asked if they smoked at all in the past 7 days [58] and, if not, whether they smoked at all in the past 30 days. The 30-day measure is recommended by the NAQC [59] and is highly correlated with prolonged abstinence measures (rs = 0.85–0.88) [58,60]. Those who report smoking in the past 7 days are asked if they quit for at least 24 h in the past 3 months. Inclusion of multiple cessation measures is consistent with best research practices for measuring abstinence [61,62]. We also ask those who participated in an intervention to rate quitline services or SFH (depending on what they selected) on usefulness (Was it helpful in quitting/ making a smoke free home?) and user experience (Would you recommend it to others?), and rate the coaches who delivered the quitline or SFH coaching on helpfulness, whether they were easy to talk to, level of expertise and empathy [63–65]. Engagement (yes/no) with components of the SFH intervention is also assessed (e.g., use of specific strategies such as having a family talk or use of SFH materials such as the stickers or pledge card) [31,47].

Quitline data.

When a participant has been reached or has received the maximum number of call attempts from the quitline, the quitline providers report enrollment status to the study team, including which quitline services were accepted (e.g., web only, full program) and whether NRT was mailed to them. In addition, at the conclusion of the study, quitline providers will share a final dataset with detailed data including the date of each completed call and call attempt.

Verification of self-reported smoking abstinence and smoke-free home.

All participants who complete a 3- or 6-month follow-up survey and report 7-day point-prevalence abstinence from smoking are offered a saliva or urine cotinine test (the type of test that was available changed after data collection began) to validate their self-report (7 days is the biochemically verifiable window for cotinine [66]). Those who accept are mailed a self-test kit containing all the necessary materials for a cotinine test and visual step-by-step instructions. The test uses a standard cut-point to identify someone as a smoker [66]. Participants are asked to text or email a digital photo of the test strip to the study team, a process found to be acceptable and feasible in prior research among a similar study sample [67]. Participants who send a photo receive a $25 gift card, regardless of test results. Two members of the study team independently view each test result photo and their consensus decision is recorded.

The first 100 participants who report creating a smoke-free home are offered in-home nicotine monitoring to validate their self-report. The Secondhand Smoking Lab provides the protocol and the monitors; they also process the results [19,68]. The protocol specifies that the monitor be hung for one week in a common space in the home, such as a living room, where air freely circulates, but away from vents or fans. Participants who return the monitor in the provided pre-addressed enveloped receive a $25 gift card regardless of the lab results. The Secondhand Smoking Lab analyzes returned monitors via gas chromatography using established methods [69,70] and returns the results to the study team. Prior research in a similar sample suggests that the monitors are used as intended, returned at a high rate, and usually confirmed self-report with no systematic biases by participant characteristics [19].

SFH intervention tracking.

SFH coaches use a database that tracks completion and content of the coaching call, including participants’ stage of readiness for creating a smoke-free home (no interest/thinking about it/decided to do it/already has a smoke-free home), perceived importance of and confidence in creating a smoke-free home (1–10 scale), reasons for wanting a smoke-free home (free response), participant engagement with mailed intervention materials (free text response), information about having a family talk (whether it occurred and if so, how it went), setting a date to create a smoke-free home (date recorded), challenges to making a smoke-free home (free response), and goals and action steps regarding a smoke-free home (free response) [27]. When recording participants’ free responses, coaches can also classify the response into pre-existing categories developed for each item.

Sample size and power analysis.

We performed an a priori power analysis using G*Power [71] to determine the sample size needed to detect quit rates of 6% in Arm 1 vs. 11% in Arm 2, 8% in Arm 1 vs. 14% in Arm 2, and 10% in Arm 1 vs. 17% in Arm 2, which correspond to intent-to-treat estimates based on previous research [72,73]. Based on previous research with a similar sample of low-income smokers recruited through 211 [74], a 40% attrition rate at 6-month follow-up (n = 1188) is expected. We plan to recruit 1980 participants, which will provide 85% power to detect 6% vs. 11% difference in quit rates at the Type I error level of 0.05.

2.6. Data analysis

The primary effectiveness research question in this Hybrid Type 2 randomized trial is whether offering SFH in addition to quitline services at the population level will increase the proportion of low-income smokers who quit by 6-month follow-up. We hypothesize that smokers in Arm 2, to whom both interventions are available, will report higher rates of smoking cessation compared to participants in Aim 1 to whom only standard quitline services are available. Intent-to-treat cessation analyses that include all smokers who complete the baseline survey provide the most conservative estimate of intervention effects. The primary outcome is self-reported 7 day point-prevalence abstinence at 6-month follow-up. The Cochran–Mantel–Haenszel test will be used to test the conditional association between study arm and abstinence at 3- and 6-month follow-up, controlling for state of residence if possible, which is a proxy for benefits offered by their state quitline. For states with a large enough sample size, a Breslow-Day test will be used to examine whether there is a common odds ratio (OR) across states.

The primary implementation research question in this Hybrid Type 2 trial is whether demand for and engagement in tobacco control services, operationalized as offer acceptance and receipt of the interventions, differs by study arm. Using the same analytical strategies and statistical methods described for the effectiveness question, we will examine cumulative probabilities of accepting quitline services by including all smokers who accept the service at baseline and follow-up surveys by arm, adjusting for baseline covariates. Finding a greater likelihood of accepting quitline services in Arm 2 (vs. Arm 1) will support our hypothesis.

Finally, we will test the hypothesis that offering SFH will move smokers who are not yet ready to quit incrementally closer to quitting. Among participants still smoking at the end of the study, the level of readiness, pessimism and ambivalence at 6-month follow-up will be regressed on study arm, states, and baseline characteristics using ordinary least squares regression. Finding greater readiness to quit, greater ambivalence about smoking, and less pessimism about quitting in Arm 2 (vs. Arm 1) would support our hypothesis.

Economic evaluation.

We will use two forms of economic evaluation to assess implementation feasibility and sustainability. First, a cost-effectiveness analysis (CEA) will compare the effects of offering SFH in addition to standard quitline services, relative to the dollar value of resources used. The primary effectiveness outcome is 7-day abstinence from smoking at 6-month follow-up, and the CEA is reported as the cost per successful quit. We will also report a CEA of achieving the implementation outcomes above: acceptance and use of quitline services. We will include only the cost of providing standard quitline and SFH services in the CEA, so these results will represent the provider perspective. Second, a cost-benefit analysis (CBA) will compare the added benefits of SFH (compared to quitline alone) in dollar terms relative to the costs of providing SFH (compared to quitline alone). The CBA will consider both individual participant and societal perspectives, spanning a broader range of both costs and benefits.

In the CEA, provider costs include “fixed costs” for setting up quitline and SFH interventions, which are invariant to the number of participants. The provider also incurs “variable costs” which depend on the scope and number of activities, primarily coaching calls, but also mailings. Data on fixed costs, materials, and supplies will be obtained from accounting records of the intervention providers. Labor costs for quitline and SFH coaching will be calculated by measuring the average duration of each call (in minutes), the average wage (including fringe benefits) of coaches who make calls, and the additional time that coaches spend on unsuccessful attempts to reach participants.

The broader cost perspective used in the CBA adds participant-level costs to the provider costs (from the CEA). The primary cost to individuals using quitline or SFH is time spent on calls and any costs related to trying to quit smoking or modifying their home environment. We will measure these with quitline and SFH usage data from providers and questions on the 3- and 6-month surveys, estimating opportunity costs using average wage rates for earners of similar demographics based on Bureau of Labor Statistics data. Discomfort from quitting is an intangible short-term “cost” but will not be valued in economic terms. States may incur lost tax revenue from reduced smoking sales, but this is a transfer at the societal level (because of savings to the individual), which results in a net social cost of zero, so this is also ignored.

Benefits in the CBA for quitline and SFH are short and long-term. Short-term gains include improved health, health-related quality of life (HRQOL), reduced SHS, and lower cigarette expenditures. Changes in cigarette expenditures will be estimated and included as an individual benefit, although this is a transfer of net zero gain to society (as with sales taxes above). We will assess health, HRQOL and SHS improvements on the surveys, but conservatively assume no short-term economic value of health or SHS. Baseline to 3 to 6 month changes in HRQOL will be measured using the SF-12 measure and a standard cost-utility framework (e.g., SF-6D algorithm), reported in quality-adjusted life years (QALYs) and valued in dollar terms [75].

Long-term benefits of quitting are numerous but difficult to value, because they accrue over decades. Direct measurement and valuation of long-term benefits is beyond the scope of our study; we will instead combine our measured (short-term) effectiveness data on cessation, SFH implementation and reduced SHS with simulation models based on the literature. Using a Markov simulation model with a range of benefits based on Sloan et al. (2004) [76] and more recent studies, we will estimate a range of low to high impacts. Individual-level impacts may vary widely and differ across states. Long-term benefits to individuals include lower health care expenditure, less mortality (valued in dollars per life year), better productivity and increased earnings. Individual gains are also counted at a societal level, but Social Security, Medicaid, Medicare and VA health plans have uncertain impacts because medium-term gains from improved health may be canceled out by costs of increased survival [76,77], likewise for pension, insurance, and disability programs. At a societal level, gains also accrue from taxes on increased wages, improved intergenerational health among youth and reduced costs due to SHS.

3. Discussion

Given the socioeconomic gradient of smoking in the U.S. [1,8], there is an urgent need to engage more low-income smokers in evidence-based activities that lead to cessation. Medicaid alone spends tens of billions of dollars annually treating smoking-related illnesses [78]. The Smoke-Free Homes: Some Things are Better Outside program has helped low-income smokers quit and create a total home smoking ban [19,36] for which there is also an immediate health benefit of decreasing exposure of household members to second-hand smoke [19]. This trial will serve as a good model for scaling up smoke-free homes interventions and help argue for adding these interventions to current quitline offerings, if found to be effective and appealing to low-income smokers.

There are some limitations to this study. All states but one used the same quitline provider, however it should be noted that this quitline provider is the most commonly used in the U.S. Also, all participants were recruited through 211 which means that each caller had other needs they were calling about and the sample may not be generalizable to all low-income smokers. Participants were not offered a direct choice between the quitline and SFH, rather the SFH offer was only made after participants declined the quitline, so we may be underestimating the number of individuals who would have preferred to start with the SFH intervention. Finally, a carbon dioxide breath test may be preferable for biochemical verification of cessation of combustible tobacco products, but due to feasibility, the constraints in this multi-state study and our past experience with both tests in a similar 211 sample [67], a mailed cotinine test was used.

Despite these limitations, this is a novel and rigorous intervention trial testing the real-world implications of offering multiple programs to reach more low-income smokers. Based on our team’s extensive prior research, we hypothesize that offering pre-cessation activities like creating smoke-free homes can increase cessation rates among low-income smokers as well as increase the number of low-income smokers engaged in evidence-based interventions.

Data availability

No data was used for the research described in the article.