Smoke-free homes, smoking susceptibility and familial smoking among never-smoking high school students: a cross-sectional analysis.

BACKGROUND Research has shown that living in a smoke-free home has a positive effect on adolescents' perceived acceptance of smoking. However, the relationship between smoke-free homes and adolescent smoking behaviours remains unclear. The aim of this study was to examine the association between smoke-free homes and smoking susceptibility among high school students, and to determine whether these associations persist when analyses are stratified by familial smoking status. METHODS We conducted a random cross-sectional survey (2012/2013 Youth Smoking Survey) of primary, junior and high school students in Canada (n = 47 203). Multivariable logistic regression analyses were used to examine the associations between smoke-free homes and susceptibility to smoking among never-smoking high school students, with and without stratification by familial smoking. RESULTS Analyses showed that adolescents living in a smoke-free home had reduced odds of being susceptible to smoking (odds ratio [OR] 0.582, 95% confidence interval [CI] 0.428-0.791) compared with their peers living in households where smoking was permitted. When adolescents had other family members who were smokers, having a smoke-free home was not significantly associated with reduced smoking susceptibility (OR 0.878, 95% CI 0.721-1.071). INTERPRETATION Our results suggest that smoke-free homes may influence future smoking initiation. Optimal success in preventing youth smoking uptake necessitates having a coherent antismoking message between the home smoking environment and familial smoking behaviour.