Changes Over Time in Absolute and Relative Socioeconomic Differences in Smoking: A Comparison of Cohort Studies From Britain, Finland, and Japan

Abstract

Introduction: Socioeconomic differences in smoking over time and across national contexts are poorly understood. We assessed the magnitude of relative and absolute social class differences in smoking in cohorts from Britain, Finland, and Japan over 5-7 years. Methods: The British Whitehall II study (n = 4350), Finnish Helsinki Health Study (n = 6328), and Japanese Civil Servants Study (n = 1993) all included employed men and women aged 35-68 at baseline in 199735-68 at baseline in -200235-68 at baseline in . Follow-up was in 200335-68 at baseline in -2007.5, and 3.6 years, respectively). Occupational social class (managers, professionals and clerical employees) was measured at baseline. Current smoking and covariates (age, marital status, body mass index, and self-rated health) were measured at baseline and follow-up. We assessed relative social class differences using the Relative Index of Inequality and absolute differences using the Slope Index of Inequality. Results: Social class differences in smoking were found in Britain and Finland, but not in Japan. Age-adjusted relative differences at baseline ranged from Relative Index of Inequality 3.08 (95% confidence interval 1.99-4.78) among Finnish men to 2.32 (1.24-4.32) among British women, with differences at follow-up greater by 8%-58%. Absolute differences remained stable and varied from Slope Index of Inequality 0.27 (0.15-0.40) among Finnish men to 0.10 (0.03-0.16) among British women. Further adjustment for covariates had modest effects on inequality indices. Conclusions: Large social class differences in smoking persisted among British and Finnish men and women, with widening tendencies in relative differences over time. No differences could be confirmed among Japanese men or women. Implications: Changes over time in social class differences in smoking are poorly understood across countries. Our study focused on employees from Britain, Finland and Japan, and found relative and absolute and class differences among British and Finnish men and women. Key covariates

Effect of early life physical growth on midlife vertebral dimensions — The Northern Finland Birth Cohort 1966 study

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