Socioeconomic status and cardiovascular disease among men: The Korean National Health Service prospective cohort study

Objectives. We examined the association between socioeconomic status (SES) and myocardial infarction and stroke subtypes, including the possible mediating influence of cardiovascular risk factors. Methods. We evaluated data on 578756 Korean male public servants aged 30 to 58 years from August 1, 1990, to July 31, 2001. Results. SES had inverse associations with mortality because of myocardial infarction and stroke subtypes, which were not changed by an adjustment for, or stratification by, cardiovascular risk factors. For nonfatal events, SES had positive, null, and inverse associations with myocardial infarction, ischemic stroke, and hemorrhagic stroke, respectively. The association between SES and nonfatal myocardial infarction depended on the presence of risk factors and was positive only among men who had cardiovascular risk factors. Case-fatality after hospital admission for cardiovascular diagnoses was significantly lower among higher SES groups, even after risk factor adjustment. Conclusions. Inverse SES associations with cardiovascular diseases were not mediated by cardiovascular risk factors among men who were undergoing economic transition. Socioeconomically patterned access to medical care may partly explain these socioeconomic gradients.