The role of national wealth in socioeconomic inequalities in smoking among 15-year-old adolescents in 34 countries. A multilevel perspective.

Background: There is evidence that inequalities in adult smoking are larger in more affluent countries. So far, the role of national wealth in socioeconomic inequalities in adolescent smoking has rarely been investigated and was only implicitly addressed by regional studies. The aim of this study is to examine the association between national wealth and socioeconomic inequalities in different aspects of adolescent tobacco use. Methods: Data were derived from the WHO-Collaborative 'Health Behaviour in School-aged Children‘ study in 2005/2006 including 60,163 15-year-old students from 34 countries. Socioeconomic position was measured using family affluence. Indicators of daily smoking, early smoking initiation and maintenance of smoking were analysed by logistic regression models adjusted for gender. The influence of national wealth on inequalities in smoking was investigated using multilevel logistic regression modelling. Results: Socioeconomic inequalities in daily smoking, early smoking initiation and maintenance of smoking strongly differed across countries and were larger among girls. Wealthier nations showed significantly larger inequalities for all measures of adolescent smoking than less affluent countries. Variations by national wealth were relative strong for inequalities in daily smoking and maintenance of smoking, and weaker for inequalities in early smoking initiation. Conclusion: The study provides first evidence showing that wealthier countries had larger socioeconomic inequalities in various dimensions of adolescent smoking than less affluent countries. Further research is required to explain the different mechanisms linking national wealth and socioeconomic inequalities in adolescent smoking.