Occupational Class and Risk of Cardiovascular Disease Incidence in Japan: Nationwide, Multicenter, Hospital‐Based Case‐Control Study

BACKGROUND: In contemporary Western settings, higher occupational class is associated with lower risk for cardiovascular disease (CVD) incidence, including coronary heart disease (CHD) and stroke. However, in non‐Western settings (including Japan), the occupational class gradient for cardiovascular disease risk has not been characterized. METHODS AND RESULTS: Using a nationwide, multicenter hospital inpatient data set (1984–2016) in Japan, we conducted a matched hospital case‐control study with ≈1.1 million study subjects. Based on a standard national classification, we coded patients according to their longest‐held occupational class (blue‐collar, service, professional, manager) within each industrial sector (blue‐collar, service, white‐collar). Using blue‐collar workers in blue‐collar industries as the referent group, odds ratios and 95% CIs were estimated by conditional logistic regression with multiple imputation, matched for sex, age, admission date, and admitting hospital. Smoking and drinking were additionally controlled. Higher occupational class (professionals and managers) was associated with excess risk for CHD. Even after controlling for smoking and drinking, the excess odds across all industries remained significantly associated with CHD, being most pronounced among managers employed in service industries (odds ratio, 1.19; 95% CI, 1.08–1.31). On the other hand, the excess CHD risk in higher occupational class was offset by their lower risk for stroke (eg, odds ratio for professionals in blue‐collar industries, 0.77; 95% CI, 0.70–0.85). CONCLUSIONS: The occupational “gradient” in cardiovascular disease (with lower risk observed in higher status occupations) may not be a universal phenomenon. In contemporary Japanese society, managers and professionals may experience higher risk for CHD.