Marital status and mortality among Japanese men and women: the Japan Collaborative Cohort Study

BACKGROUND Several studies have indicated a significant association between marital status and mortality risks. However, most of these studies have compared married and unmarried people without differentiating among single, divorced and widowed status. Moreover, gender differences in mortality rates associated with marital status have not been sufficiently clarified. With significant increases in the percentages of divorced and widowed people and a corresponding drop in the marriage rate in Japan during the past two or three decades, it can be expected that these changes will have a significant impact on mortality rates. METHODS This investigation used a prospective study of a total of 94,062 Japanese men and women aged 40-79 who completed self-administered questionnaires at baseline and during a followed-up of 9.9-years. RESULTS Compared with married men, never-married men showed higher risks of mortality from cardiovascular disease [relative risk (RR) = 3.05, 95% confidence interval (CI) 2.03-4.60], respiratory disease (RR = 2.43, 95%CI 1.27-4.63), external causes (RR = 2.18, 95%CI 1.05-4.54) and all causes (RR = 1.91, 95%CI 1.51-2.42) after adjustment for potentially confounding variables. For never-married women, there was a smaller but significantly higher risk of mortality from all causes (RR = 1.46, 95%CI 1.15-1.84). Divorced and widowed men showed moderately higher risks of mortality from cardiovascular disease, external causes and all causes compared with married men, but such a trend was not observed in women. CONCLUSION Single status was associated with a higher risk of mortality than was married status for both men and women. Divorce and widowhood were associated with elevated risk for men, but not for women. These findings suggest single, divorce and widowhood status constitute potentially adverse health effects.