Objectives: The aim of this study is to analyse longitudinally, the annual effects of age group and birth cohort on smoking in the Swedish population during a 24-year period and to analyse the smoking trends for different levels of education.
Methods: A random sample of adult, non-institutionalized persons aged 16-71 years was interviewed every 8 years by professional interviewers. In addition to three time-related variables--year of interview, age at the time of the interview, and year of birth--we included the following explanatory variables in the analyses: sex, educational level, and urbanization.
Results: We found significant decreases in smoking prevalence in all studied subgroups. The adjusted odds ratios for age were 0.89 (95 % CI 0.88-0.90) and 0.92 (95 % CI 0.91-0.93) for men and women, respectively. The decreases in smoking over time were significant in all levels of education, except for in women with low educational level.
Conclusions: In Sweden, the prevalence of smoking has decreased in most age groups and cohorts, and in persons in most levels of education, albeit less so in women with low educational level.