Socioeconomic Indicators and Cardiovascular Disease Incidence Among Japanese Community Residents: The Jichi Medical School Cohort Study

Background There has been little research in inequalities in risk of cardiovascular disease incidence by social class in Asia. Purpose The purpose of this study was to examine the association between socioeconomic indicators and risk of stroke and coronary heart disease in Japan. Method Data from the Jichi Medical School Study, a population-based prospective cohort study of approximately 11,000 Japanese men and women, were used. The average follow-up period was 11.7 years. Age- and area-adjusted hazard ratios with 95% confidence intervals (CIs) for education level/occupation were calculated using Cox proportional hazard regression analysis. Results Compared to those who completed education at age 14 or younger, the age and area-adjusted hazard ratios of intraparenchymal hemorrhage incidence for men who completed education at age 15–17 and at age 18 or older were 0.42 (95% CI, 0.21–0.84) and 0.34 (95% CI, 0.14–0.84), respectively. The age- and area-adjusted hazard ratios of intraparenchymal hemorrhage and subarachnoid hemorrhage incidence for female white-collar workers compared to female blue-collar workers were 0.28 (95% CI, 0.08–0.98) and 3.23 (95% CI, 1.29, 8.01), respectively. No associations were found between education level and risk of coronary heart disease among both men and women. Conclusion These results suggest the pattern of social inequalities in health in Japan might be different from that in Western countries.