Subsistence difficulties are associated with more barriers to quitting and worse abstinence outcomes among homeless smokers: evidence from two studies in Boston, Massachusetts

Abstract

Background: Three-quarters of homeless people smoke cigarettes. Competing priorities for shelter, food, and other subsistence needs may be one explanation for low smoking cessation rates in this population. We analyzed data from two samples of homeless smokers to examine the associations between subsistence difficulties and 1) smoking cessation readiness, confidence, and barriers in a cross-sectional study, and 2) smoking abstinence during follow-up in a longitudinal study.

Methods: We conducted a survey of homeless smokers (N = 306) in 4/2014-7/2014 and a pilot randomized controlled trial (RCT) for homeless smokers (N = 75) in 10/2015-6/2016 at Boston Health Care for the Homeless Program. In both studies, subsistence difficulties were characterized as none, low, or high based on responses to a 5-item scale assessing the frequency of past-month difficulty finding shelter, food, clothing, a place to wash, and a place to go to the bathroom. Among survey participants, we used linear regression to assess the associations between subsistence difficulty level and readiness to quit, confidence to quit, and a composite measure of perceived barriers to quitting. Among RCT participants, we used repeated-measures logistic regression to examine the association between baseline subsistence difficulty level and carbon monoxide-defined brief smoking abstinence assessed 14 times over 8 weeks of follow-up. Analyses adjusted for demographic characteristics, substance use, mental illness, and nicotine dependence.

Results: Subsistence difficulties were common in both study samples. Among survey participants, greater subsistence difficulties were associated with more perceived barriers to quitting (p < 0.001) but not with cessation readiness or confidence. A dose-response relationship was observed for most barriers, particularly psychosocial barriers. Among RCT participants, greater baseline subsistence difficulties predicted less smoking abstinence during follow-up in a dose-response fashion. In adjusted analyses, individuals with the highest level of subsistence difficulty had one-third the odds of being abstinent during follow-up compared to those without subsistence difficulties (OR 0.33, 95% CI 0.11-0.93) despite making a similar number of quit attempts.

Conclusions: Homeless smokers with greater subsistence difficulties perceive more barriers to quitting and are less likely to do so despite similar readiness, confidence, and attempts. Future studies should assess whether addressing subsistence difficulties improves cessation outcomes in this population.

Trial registration: ClinicalTrials.gov: NCT02565381 .

Keywords: Homeless persons; Smoking cessation; Social determinants of health; Subsistence difficulties; Tobacco use.

Fig. 1

Subsistence difficulties in (a) the survey sample (N = 306) and (b) the RCT sample (N = 75)

Fig. 2

Associations between subsistence difficulty level and specific smoking cessation barriers in the cross-sectional survey sample (N = 306). Abbreviations: AOR, adjusted odds ratio; CI, confidence interval Analytic notes: AORs are from ordinal logistic regression models, each controlling for age, gender, race/ethnicity, education, past-month work, past-month income, general health status, drug use severity, alcohol use severity, psychiatric symptom severity, and nicotine dependence. Odds ratios from ordinal logistic regression models represent both the odds of reporting a large or small barrier vs. no barrier and the odds of reporting a large barrier vs. a small or no barrier. The score test of proportional odds was significant for “cost of cessation medications.” Alternative model specifications (see text) did not alter the inference. Due to the exploratory nature of these analyses, the significance level was not adjusted for multiple comparisons.

Fig. 3

Smoking abstinence^a during follow-up by level of subsistence difficulty among RCT participants (N = 75). ^aDefined as an exhaled carbon monoxide < 8 ppm