Trial Outcomes & Findings for Efficacy of a Smoke-Free Homes Intervention (NCT NCT04547686)

NCT ID: NCT04547686

Last Updated: 2026-08-18

Results Overview

Smoking cessation/abstinence is assessed as cotinine-validated 7-day point-prevalence abstinence at 12 months. Saliva samples were collected via mail from participants who report 7-day (and/or 30-day) point-prevalence abstinence at 12-month follow-up in order to examine cotinine levels to verify self-reported abstinence. A standard cut point for cotinine of 15 ng/ml is used to determine abstinence.

Recruitment status

COMPLETED

Study phase

NA

Target enrollment

916 participants

Primary outcome timeframe

12 months

Results posted on

2026-08-18

Participant Flow

Participants were referred by primary care providers of participating Federally Qualified Health Centers (FQHC) in Georgia, USA. Participant enrollment began November 11, 2020 and all follow-up assessments were completed by July 27, 2025.

Participant milestones

Participant milestones
Measure
Smoke-Free Homes Intervention
Participants in the intervention condition received the expanded Smoke-Free Homes intervention coupled with a connection to the quitline. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. Smoke-Free Homes Intervention: The adapted smoke-free homes intervention consists of five components, three interactive mailings and two coaching calls, focused on creating home and vehicle(s) smoking bans among smokers. The intervention is based on principles of Social Cognitive Theory and the Transtheoretical Model's stages of change. The rationale underlying the intervention is that creation of additional smoke-free environments will reduce situational and environmental cues to smoke, reduce opportunities and places to smoke, increase self-efficacy for quitting and increase motivation to quit. The intervention uses persuasion, role modeling, behavioral contracting and goal setting to move smokers through behavioral capability, outcome expectations and self-efficacy for strict smoke-free rules, creation of and compliance/enforcement with smoke-free rules, reduced cigarettes smoked per day, increased motivation to quit, increased quit attempts, and successful cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Control
The usual care/control arm received mailed information on the quitline and a connection to the quitline at their request. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Overall Study
STARTED
467
449
Overall Study
COMPLETED
262
309
Overall Study
NOT COMPLETED
205
140

Reasons for withdrawal

Reasons for withdrawal
Measure
Smoke-Free Homes Intervention
Participants in the intervention condition received the expanded Smoke-Free Homes intervention coupled with a connection to the quitline. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. Smoke-Free Homes Intervention: The adapted smoke-free homes intervention consists of five components, three interactive mailings and two coaching calls, focused on creating home and vehicle(s) smoking bans among smokers. The intervention is based on principles of Social Cognitive Theory and the Transtheoretical Model's stages of change. The rationale underlying the intervention is that creation of additional smoke-free environments will reduce situational and environmental cues to smoke, reduce opportunities and places to smoke, increase self-efficacy for quitting and increase motivation to quit. The intervention uses persuasion, role modeling, behavioral contracting and goal setting to move smokers through behavioral capability, outcome expectations and self-efficacy for strict smoke-free rules, creation of and compliance/enforcement with smoke-free rules, reduced cigarettes smoked per day, increased motivation to quit, increased quit attempts, and successful cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Control
The usual care/control arm received mailed information on the quitline and a connection to the quitline at their request. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Overall Study
Death
2
0
Overall Study
Lost to Follow-up
169
121
Overall Study
Withdrawal by Subject
32
19
Overall Study
Unhoused
1
0
Overall Study
Terminal illness
1
0

Baseline Characteristics

Efficacy of a Smoke-Free Homes Intervention

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure
Smoke-Free Homes Intervention
n=467 Participants
Participants in the intervention condition received the expanded Smoke-Free Homes intervention coupled with a connection to the quitline. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. Smoke-Free Homes Intervention: The adapted smoke-free homes intervention consists of five components, three interactive mailings and two coaching calls, focused on creating home and vehicle(s) smoking bans among smokers. The intervention is based on principles of Social Cognitive Theory and the Transtheoretical Model's stages of change. The rationale underlying the intervention is that creation of additional smoke-free environments will reduce situational and environmental cues to smoke, reduce opportunities and places to smoke, increase self-efficacy for quitting and increase motivation to quit. The intervention uses persuasion, role modeling, behavioral contracting and goal setting to move smokers through behavioral capability, outcome expectations and self-efficacy for strict smoke-free rules, creation of and compliance/enforcement with smoke-free rules, reduced cigarettes smoked per day, increased motivation to quit, increased quit attempts, and successful cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Control
n=449 Participants
The usual care/control arm received mailed information on the quitline and a connection to the quitline at their request. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Total
n=916 Participants
Total of all reporting groups
Age, Continuous
49.9 years
STANDARD_DEVIATION 12.86 • n=298 Participants
51.4 years
STANDARD_DEVIATION 12.60 • n=102 Participants
50.6 years
STANDARD_DEVIATION 12.75 • n=400 Participants
Sex/Gender, Customized
Female
316 Participants
n=298 Participants
297 Participants
n=102 Participants
613 Participants
n=400 Participants
Sex/Gender, Customized
Male
150 Participants
n=298 Participants
150 Participants
n=102 Participants
300 Participants
n=400 Participants
Sex/Gender, Customized
Other
1 Participants
n=298 Participants
2 Participants
n=102 Participants
3 Participants
n=400 Participants
Race/Ethnicity, Customized
Non-Hispanic White
139 Participants
n=298 Participants
137 Participants
n=102 Participants
276 Participants
n=400 Participants
Race/Ethnicity, Customized
Non-Hispanic Black
296 Participants
n=298 Participants
284 Participants
n=102 Participants
580 Participants
n=400 Participants
Race/Ethnicity, Customized
Hispanic
13 Participants
n=298 Participants
13 Participants
n=102 Participants
26 Participants
n=400 Participants
Race/Ethnicity, Customized
More than one race
11 Participants
n=298 Participants
6 Participants
n=102 Participants
17 Participants
n=400 Participants
Race/Ethnicity, Customized
Other
1 Participants
n=298 Participants
2 Participants
n=102 Participants
3 Participants
n=400 Participants
Race/Ethnicity, Customized
Unknown or not reported
7 Participants
n=298 Participants
7 Participants
n=102 Participants
14 Participants
n=400 Participants
Region of Enrollment
United States
467 Participants
n=298 Participants
449 Participants
n=102 Participants
916 Participants
n=400 Participants
Education
Less than High School/some High School
146 Participants
n=298 Participants
129 Participants
n=102 Participants
275 Participants
n=400 Participants
Education
High School/General Educational Development (GED)
187 Participants
n=298 Participants
189 Participants
n=102 Participants
376 Participants
n=400 Participants
Education
Vocational-technical school/some college
84 Participants
n=298 Participants
97 Participants
n=102 Participants
181 Participants
n=400 Participants
Education
College graduate
50 Participants
n=298 Participants
34 Participants
n=102 Participants
84 Participants
n=400 Participants
Household size
1 Person Living in Household
104 Participants
n=298 Participants
113 Participants
n=102 Participants
217 Participants
n=400 Participants
Household size
2 People Living in Household
146 Participants
n=298 Participants
131 Participants
n=102 Participants
277 Participants
n=400 Participants
Household size
3 People Living in Household
76 Participants
n=298 Participants
103 Participants
n=102 Participants
179 Participants
n=400 Participants
Household size
4 People Living in Household
72 Participants
n=298 Participants
47 Participants
n=102 Participants
119 Participants
n=400 Participants
Household size
5 or More People Living in Household
68 Participants
n=298 Participants
54 Participants
n=102 Participants
122 Participants
n=400 Participants
Household size
Missing
1 Participants
n=298 Participants
1 Participants
n=102 Participants
2 Participants
n=400 Participants

PRIMARY outcome

Timeframe: 12 months

Population: The self-report analysis includes participants who responded to the question about smoking abstinence during the survey at Month 12.The cotinine validated analysis includes participants who reported quitting smoking at Month 12 and provided a saliva sample for cotinine analysis.

Smoking cessation/abstinence is assessed as cotinine-validated 7-day point-prevalence abstinence at 12 months. Saliva samples were collected via mail from participants who report 7-day (and/or 30-day) point-prevalence abstinence at 12-month follow-up in order to examine cotinine levels to verify self-reported abstinence. A standard cut point for cotinine of 15 ng/ml is used to determine abstinence.

Outcome measures

Outcome measures
Measure
Smoke-Free Homes Intervention
n=262 Participants
Participants in the intervention condition received the expanded Smoke-Free Homes intervention coupled with a connection to the quitline. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. Smoke-Free Homes Intervention: The adapted smoke-free homes intervention consists of five components, three interactive mailings and two coaching calls, focused on creating home and vehicle(s) smoking bans among smokers. The intervention is based on principles of Social Cognitive Theory and the Transtheoretical Model's stages of change. The rationale underlying the intervention is that creation of additional smoke-free environments will reduce situational and environmental cues to smoke, reduce opportunities and places to smoke, increase self-efficacy for quitting and increase motivation to quit. The intervention uses persuasion, role modeling, behavioral contracting and goal setting to move smokers through behavioral capability, outcome expectations and self-efficacy for strict smoke-free rules, creation of and compliance/enforcement with smoke-free rules, reduced cigarettes smoked per day, increased motivation to quit, increased quit attempts, and successful cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Control
n=308 Participants
The usual care/control arm received mailed information on the quitline and a connection to the quitline at their request. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Number of Participants Achieving Smoking Cessation/Abstinence
Self-reported smoking cessation/abstinence
60 Participants
66 Participants
Number of Participants Achieving Smoking Cessation/Abstinence
Cotinine validated cessation/abstinence
22 Participants
19 Participants

SECONDARY outcome

Timeframe: 6 months, 12 months

Population: This analysis includes participants who responded to the 30-day smoking cessation question of the surveys administered at 6 and 12 months. Some participants were lost to follow-up and did not complete the surveys.

Participants self-report abstinence from smoking during the prior 30 days.

Outcome measures

Outcome measures
Measure
Smoke-Free Homes Intervention
n=288 Participants
Participants in the intervention condition received the expanded Smoke-Free Homes intervention coupled with a connection to the quitline. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. Smoke-Free Homes Intervention: The adapted smoke-free homes intervention consists of five components, three interactive mailings and two coaching calls, focused on creating home and vehicle(s) smoking bans among smokers. The intervention is based on principles of Social Cognitive Theory and the Transtheoretical Model's stages of change. The rationale underlying the intervention is that creation of additional smoke-free environments will reduce situational and environmental cues to smoke, reduce opportunities and places to smoke, increase self-efficacy for quitting and increase motivation to quit. The intervention uses persuasion, role modeling, behavioral contracting and goal setting to move smokers through behavioral capability, outcome expectations and self-efficacy for strict smoke-free rules, creation of and compliance/enforcement with smoke-free rules, reduced cigarettes smoked per day, increased motivation to quit, increased quit attempts, and successful cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Control
n=323 Participants
The usual care/control arm received mailed information on the quitline and a connection to the quitline at their request. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Number of Participants Self-reporting 30-day Abstinence
Month 12
49 Participants
52 Participants
Number of Participants Self-reporting 30-day Abstinence
Month 6
45 Participants
42 Participants

SECONDARY outcome

Timeframe: 6 months,12 months

Population: This analysis includes participants who are daily smokers and who responded to the survey question about number of cigarettes smoked per day.

Participants are asked to report the number of cigarettes smoked per day, for daily smokers, on days that they smoked.

Outcome measures

Outcome measures
Measure
Smoke-Free Homes Intervention
n=117 Participants
Participants in the intervention condition received the expanded Smoke-Free Homes intervention coupled with a connection to the quitline. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. Smoke-Free Homes Intervention: The adapted smoke-free homes intervention consists of five components, three interactive mailings and two coaching calls, focused on creating home and vehicle(s) smoking bans among smokers. The intervention is based on principles of Social Cognitive Theory and the Transtheoretical Model's stages of change. The rationale underlying the intervention is that creation of additional smoke-free environments will reduce situational and environmental cues to smoke, reduce opportunities and places to smoke, increase self-efficacy for quitting and increase motivation to quit. The intervention uses persuasion, role modeling, behavioral contracting and goal setting to move smokers through behavioral capability, outcome expectations and self-efficacy for strict smoke-free rules, creation of and compliance/enforcement with smoke-free rules, reduced cigarettes smoked per day, increased motivation to quit, increased quit attempts, and successful cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Control
n=153 Participants
The usual care/control arm received mailed information on the quitline and a connection to the quitline at their request. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Number of Cigarettes Smoked Per Day on Smoking Days
Month 6
11.82 cigarettes/day
Standard Deviation 8.97
11.48 cigarettes/day
Standard Deviation 6.73
Number of Cigarettes Smoked Per Day on Smoking Days
Month 12
10.67 cigarettes/day
Standard Deviation 7.92
11.11 cigarettes/day
Standard Deviation 6.31

SECONDARY outcome

Timeframe: 6 months, 12 months

Population: This analysis includes smoking participants who responded to the survey item asking about attempts to quit smoking.

Participants were asked "How many times during the past 6 months have you stopped smoking for more than one day because you were trying to quit smoking?" to assess the number of attempts to quit smoking.

Outcome measures

Outcome measures
Measure
Smoke-Free Homes Intervention
n=243 Participants
Participants in the intervention condition received the expanded Smoke-Free Homes intervention coupled with a connection to the quitline. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. Smoke-Free Homes Intervention: The adapted smoke-free homes intervention consists of five components, three interactive mailings and two coaching calls, focused on creating home and vehicle(s) smoking bans among smokers. The intervention is based on principles of Social Cognitive Theory and the Transtheoretical Model's stages of change. The rationale underlying the intervention is that creation of additional smoke-free environments will reduce situational and environmental cues to smoke, reduce opportunities and places to smoke, increase self-efficacy for quitting and increase motivation to quit. The intervention uses persuasion, role modeling, behavioral contracting and goal setting to move smokers through behavioral capability, outcome expectations and self-efficacy for strict smoke-free rules, creation of and compliance/enforcement with smoke-free rules, reduced cigarettes smoked per day, increased motivation to quit, increased quit attempts, and successful cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Control
n=282 Participants
The usual care/control arm received mailed information on the quitline and a connection to the quitline at their request. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Number of Quit Attempts
Month 6
3.26 attempts per participant
Standard Deviation 5.93
3.25 attempts per participant
Standard Deviation 8.24
Number of Quit Attempts
Month 12
3.36 attempts per participant
Standard Deviation 4.73
3.02 attempts per participant
Standard Deviation 4.01

SECONDARY outcome

Timeframe: 6 months, 12 months

Population: This analysis includes participants who responded to the smoke-free home rules question of the surveys administered at 6 and 12 months. Some participants were lost to follow-up and did not complete the follow-up surveys.

Participants were asked to describe the rules about cigarette smoking inside their home. Possible responses are: There are no rules about smoking inside the home; Smoking is not allowed anywhere inside the home; Smoking is allowed in some places or at sometimes; Smoking is allowed anywhere inside the home. Responses are categorized as the home being smoke-free or not.

Outcome measures

Outcome measures
Measure
Smoke-Free Homes Intervention
n=287 Participants
Participants in the intervention condition received the expanded Smoke-Free Homes intervention coupled with a connection to the quitline. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. Smoke-Free Homes Intervention: The adapted smoke-free homes intervention consists of five components, three interactive mailings and two coaching calls, focused on creating home and vehicle(s) smoking bans among smokers. The intervention is based on principles of Social Cognitive Theory and the Transtheoretical Model's stages of change. The rationale underlying the intervention is that creation of additional smoke-free environments will reduce situational and environmental cues to smoke, reduce opportunities and places to smoke, increase self-efficacy for quitting and increase motivation to quit. The intervention uses persuasion, role modeling, behavioral contracting and goal setting to move smokers through behavioral capability, outcome expectations and self-efficacy for strict smoke-free rules, creation of and compliance/enforcement with smoke-free rules, reduced cigarettes smoked per day, increased motivation to quit, increased quit attempts, and successful cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Control
n=323 Participants
The usual care/control arm received mailed information on the quitline and a connection to the quitline at their request. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Number of Participants With Smoke-free Home Rules
Month 6: smoking is not allowed anywhere inside the home
192 Participants
183 Participants
Number of Participants With Smoke-free Home Rules
Month 12: smoking is not allowed anywhere inside the home
180 Participants
182 Participants

SECONDARY outcome

Timeframe: 6 months, 12 months

Population: This analysis includes participants who responded to the smoke-free vehicle rules question of the surveys administered at 6 and 12 months. Some participants were lost to follow-up and did not complete the follow-up surveys.

Participants were asked to describe the rules about cigarette smoking inside their vehicle. Possible responses are: There are no rules about smoking inside vehicles; Smoking is sometimes allowed in some vehicles; Smoking is never allowed in any vehicle; No vehicle. Responses are categorized as vehicles being smoke-free or not.

Outcome measures

Outcome measures
Measure
Smoke-Free Homes Intervention
n=229 Participants
Participants in the intervention condition received the expanded Smoke-Free Homes intervention coupled with a connection to the quitline. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. Smoke-Free Homes Intervention: The adapted smoke-free homes intervention consists of five components, three interactive mailings and two coaching calls, focused on creating home and vehicle(s) smoking bans among smokers. The intervention is based on principles of Social Cognitive Theory and the Transtheoretical Model's stages of change. The rationale underlying the intervention is that creation of additional smoke-free environments will reduce situational and environmental cues to smoke, reduce opportunities and places to smoke, increase self-efficacy for quitting and increase motivation to quit. The intervention uses persuasion, role modeling, behavioral contracting and goal setting to move smokers through behavioral capability, outcome expectations and self-efficacy for strict smoke-free rules, creation of and compliance/enforcement with smoke-free rules, reduced cigarettes smoked per day, increased motivation to quit, increased quit attempts, and successful cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Control
n=258 Participants
The usual care/control arm received mailed information on the quitline and a connection to the quitline at their request. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Number of Participants Smoke-free Vehicle Rules
Month 6: smoking is never allowed in any vehicle
123 Participants
96 Participants
Number of Participants Smoke-free Vehicle Rules
Month 12: smoking is never allowed in any vehicle
103 Participants
97 Participants

SECONDARY outcome

Timeframe: 6 months,12 months

Population: This analysis includes participants who responded to the survey item about the number of cigarettes smoked inside the home at Months 6 and 12. Some participants were lost to follow-up.

Participants were asked to report the number of cigarettes smoked inside the home on a typical day, during the last 7 days.

Outcome measures

Outcome measures
Measure
Smoke-Free Homes Intervention
n=287 Participants
Participants in the intervention condition received the expanded Smoke-Free Homes intervention coupled with a connection to the quitline. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. Smoke-Free Homes Intervention: The adapted smoke-free homes intervention consists of five components, three interactive mailings and two coaching calls, focused on creating home and vehicle(s) smoking bans among smokers. The intervention is based on principles of Social Cognitive Theory and the Transtheoretical Model's stages of change. The rationale underlying the intervention is that creation of additional smoke-free environments will reduce situational and environmental cues to smoke, reduce opportunities and places to smoke, increase self-efficacy for quitting and increase motivation to quit. The intervention uses persuasion, role modeling, behavioral contracting and goal setting to move smokers through behavioral capability, outcome expectations and self-efficacy for strict smoke-free rules, creation of and compliance/enforcement with smoke-free rules, reduced cigarettes smoked per day, increased motivation to quit, increased quit attempts, and successful cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Control
n=324 Participants
The usual care/control arm received mailed information on the quitline and a connection to the quitline at their request. Follow-up assessments occurred at six and twelve months, including saliva cotinine validation for reported 7-day cessation. The quitline is a phone number that people can call that offers free smoking cessation counseling to all Georgia residents by the state of Georgia.
Number of Cigarettes Smoked in the Home
Month 6
2.16 cigarettes
Standard Deviation 4.41
3.13 cigarettes
Standard Deviation 4.84
Number of Cigarettes Smoked in the Home
Month 12
2.44 cigarettes
Standard Deviation 5.87
2.93 cigarettes
Standard Deviation 5.37

Adverse Events

Smoke-Free Homes Intervention

Serious events: 0 serious events
Other events: 0 other events
Deaths: 2 deaths

Control

Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Michelle Kegler, DrPH

Emory University

Phone: 404-712-9957

Results disclosure agreements

  • Principal investigator is a sponsor employee
  • Publication restrictions are in place