Excess mortality from avoidable and non-avoidable causes in men of low socioeconomic status: a prospective study in Korea

Study objective-The objective of this study was to evaluate the magnitude a nd contributory factors of socioeconomic differentials in mortality in a co hort of Korean male civil servants. Design-A prospective observational study of male civil servants followed up for five years after baseline measurement. Setting-All civil service offices in Korea. Participants and measurements-The study was conducted on 759 665 Korean mal e public servants aged 30-64 at baseline examination in 1992. The grade of monthly salary of these participants divided into four groups, a proxy indi cator of socioeconomic status (SES), was the main predictive variable. Mort ality of the participants was followed up from 1992 to 1996. The causes of deaths were categorised into four groups according to the medical amenabili ty: avoidable, partly avoidable, non-avoidable, and external causes of deat h. The risk of mortality associated with SES was estimated using the Cox pr oportional hazard model. Main results-lowest SES group had significantly higher risk of mortality fr om most causes compared with the highest SES group in the order of external cause (relative risk (RR): 2.26), avoidable (RR: 1.65), all cause (RR: 1.5 9), and non-avoidable mortality (RR: 1.54). With the adjustment of known ri sk factors, significantly higher risks of mortality in lowest SES group wer e attenuated but persisted. Looking at the deaths from partly avoidable cau ses, significantly higher risks of mortality in the lowest SES group was ob served from cerebrovascular disease but not from coronary heart disease. Conclusions-Socioeconomic differentials in non-avoidable as well as avoidab le mortality, persisting even under the control of risk factors, suggest th at mortality is influenced not only by the quality of health care and diffe rent distribution of risk factors but also by other aspects of SES that are yet unknown.