Evolution of the association between parental and child smoking in Finland between 1977 and 2005

Objectives To study changes in the family smoking profile and in the association between parental and child smoking from 1977 to 2005. Methods Data was based on biennial surveys using nationally-representative samples of 14–18-year-old Finns (n = 58,279). Response rate ranged between 88% (1977) and 65% (2005). Parental smoking categories were: two smoking parents, smoking father, smoking mother, both currently non-smokers but one or both ex-smokers, and two never-smoking parents. Child smoking categories were: experimental, daily, and never. Associations between parental and child smoking were examined using multinomial logistic regression models. Results Over the study period, the proportion of never-smoking families (child and parents never-smokers) increased (9% vs. 18%). Age, sex, family structure, and survey decade adjusted odds ratios for childʹs daily smoking were 6.9 (95% CI: 6.4, 7.5) when both parents smoked, 4.7 (95% CI: 4.3, 5.2) when mother smoked, 3.8 (95% CI: 3.5, 4.1) when father smoked, and 2.8 (95% CI: 2.6, 2.9) when one/both were ex-smokers compared with children of never-smoking parents. Only a few non-systematic interactions between parental smoking and survey decade were found. Conclusions The proportion of totally smoke-free families increased substantially. Association between parental and child smoking persisted strong and mainly similar over time.