Background:
Smoke-free policy is associated with smoking reduction; however, it is unknown if the reduction in smoking intensity occurs across the stages of smoking cessation, and there is paucity of literature on the relationship between home smoking rule and smoking intensity in low- and middle-income countries (LMICs). The aim of this study was to conduct a cross-country evaluation of the relationship between home smoking rule and smoking intensity among smokers in different stages of smoking cessation.

Methods:
Data from 39,204 current smokers from the Global Adult Survey (GATS), 2009-2012 from 17 LMICs were analyzed. Weighted multiple linear regression analyses were conducted using the log of smoking intensity as the outcome variable with home smoking rule as the main independent variable. Adjusted regression coefficients (β) with associated 95% confidence intervals (CI) were estimated.

Results:
Overall, the average smoking intensity was approximately 15, 14, and 13 for home smoking allowed, smoking restriction and smoke-free rules, respectively. There was a 12.7% (95% CI=7.6%-17.8%) and a 22.5% (95% CI=17.1%-28.0%) reduction in smoking intensity among adults in precontemplation from homes with smoking restriction and smoke-free rules, respectively. Among adults in contemplation, smoking restriction and smoke-free rules were associated with a 21.5% (95% CI=6.0%-36.9%) and an 18.6% (95% CI=9.0%-28.2%) reduction in smoking intensity, respectively. For adults in preparation, smoke-free rule was associated with a 19.4% (95% CI=3.9%-34.9%) reduction in smoking intensity.

Conclusions:
Smoke-free homes are associated with a significant reduction in smoking intensity across the first three stages of the transtheoretical model. This suggests that, banning public smoking may have added benefit by reducing smoking intensity, since evidence suggests that people who work in smoke-free environments are more likely to live in smoke-free homes.