Introduction:
The home is the primary source of secondhand tobacco smoke (SHS) exposure for children and adult non-smokers. Voluntary smoking rules in a household affect the amount of SHS exposure of household members at home and ultimately impact their health. The objectives of this study were: 1) to evaluate the prevalence and 2) to identify the determinants of having smoking ban at home among Spanish adult smokers in 2021.

Material and Methods:
Data were drawn from the 2021 International Tobacco Control (ITC) Spain Survey, a nationally representative sample of adult smokers aged ≥18 years (n=1,006). Data were collected between June and August 2021 either in-person or via telephone. Study measures included demographics, household structure, smoking characteristics (nicotine dependence, number of cigarettes per day, etc.), beliefs regarding SHS harm, and smoking rules in the household (complete, partial or no ban). Proportions, 95% confidence intervals (CI), and prevalence ratios (PR) of having a smoke-free home among smokers were computed by means of generalised linear models adjusted for sex, age, and educational status.

Results:
The prevalence of smokers’ homes with complete smoking bans was 31.6% (95%CI: 27.8-35.2) and of homes with partial bans was 42.3% (38.5-46.2). Among smokers, the following characteristics were significantly associated with smoke-free rules: being 55 years or older vs. being 18-24 years old (PR=1.76; 1.15-2.70), having a medium educational level vs. a lower one (1.29; 1.08-1.54), living with minors vs. not (1.60; 1.31-1.96), being a non-daily smoker (1.63; 1.23-2.16) or a recent quitter (1.67; 1.44-1.95) vs. daily smoker, having low vs. high nicotine dependence (2.21; 1.17-4.19), and agreeing that SHS is harmful to non-smokers vs. other than agree (0.52; 0.37-0.73).

Conclusions:
The prevalence of smoke-free homes among Spanish smokers is low. There is an association between adopting smoke-free rules and older age, educational level, living with minors, low nicotine dependence, and smokers’ knowledge of the harmful health effects of SHS.