The effects of voluntary home smokefree rule on smoking cessation

Several studies have found that a smokefree home is not only associated with the decreased secondhand smoke exposure, but also the increased smoking cessation, with some studies indicating that home smokefree rules may have a larger association with increased cessation than smokefree workplaces.

However, prohibitions against smoking in the home setting are generally not mandated by law. It could be considered “voluntary” and is implemented by agreement among household members. Because the home smokefree rule is voluntarily adopted, having a home smokefree rule may reflect smokers’ as well as their adult nonsmoking household members’ attitudes against cigarette smoking. Such home smokefree rule confounded with household members’ antismoking attitudes as well as smoker’s preparation stage on quit smoking may explain why the strong association between home smokefree rule adoption and smoking cessation are presented in previous studies.

While a handful of studies examining the influences of home smokefree rules on smoking cessation used cross-sectional, or even longitudinal data to ensure home smokefree rule happened before smoking cessation, the existing literatures did not explain to what degree the association between home smokefree rules and improved cessation behaviors is due to the unobserved motivation to quit smoking, the unobserved household members’ preference against smoking, or the resultant inconvenience of smoking.

This study fills in this gap by investigating the causal relationship between home smokefree rule and smoking cessation. This study uses the Tobacco Use Supplements to Current Population Survey 2001 – 2011, and proposes to use an instrumental variable approach to overcome the endogeneity issue in investigating the effect of home smokefree rule. This study uses whether the spouse reported that s/he worked in a smokefree workplace as an instrument of home smokefree rule, because several studies found that smoking restrictions in public places encourage voluntary adoption of smokefree rule in the home venue even for the households with smokers. Variables for smoking cessation are weather one has quitted smoking for more than 6 months, whether one has reduced number of cigarettes smoked from last year to the present, and whether one has made any quit attempts last year.

The preliminary results indicate that in the OLS model, the adoption of home smokefree rule is significantly associated with the increased likelihood of smoking cessation. However, the 2SLS does not provide any evidence such that home smokefree rule increased smoking cessation. The first stage of the 2SLS indicates that the instrument (whether the spouse works in a smokefree worksite) is powerfully predicting the likelihood of home smokefree rule adoption (F statistic is over 10).

This study aims to inform tobacco control policy making and program design to recognize the role of quit motivation when they promote the home smokefree policies to reach their target on encouraging smoking cessation on population level.