Best friend's and family members’ smoking habits and parental divorce during childhood are associated with smoking in adulthood

Abstract

Aims Smoking initiation during childhood or adolescence is strongly associated with friends’ smoking. Likewise, adverse living conditions increase the likelihood of future deviant behaviour. We examine whether smoking by a best friend and family members during school years as well as adverse childhood experiences are associated with smoking in adulthood. Data and Design We have analysed the responses of Finnish working-aged respondents in 1998 (N=25901) and 2003 (N=20773) to questions on the smoking status of friends and family members during school years as well as their answers on a six-item scale of childhood adversities. A case-control study design was used to compare current cigarette smokers (1998 and 2003) to non-smokers (1998 and 2003). Results If a best friend during school years was a smoker, the subject s odds ratio (OR) of being a smoker in adulthood was 4.43 among females and 3.91 among males compared to those with a non-smoking best friend in multivariate models adjusted for smoking by family members during school years and by six childhood adversities. These associations did not differ by age. Smoking in adulthood was associated with childhood adversities, most strongly with parental divorce or separation during the subjects’ school years. Conclusion Smoking by a best friend and parental divorce or separation during school years appears to be a strong factor of smoking in later life.