Socioeconomic indicators and cardiovascular disease incidence among Japanese community residents: the Jichi Medical School Cohort Study

Abstract

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.