Educational Inequality in Obesity-Related Mortality in Korea

The prevalence of obesity has been increasing worldwide, which raises concerns about the disease burden associated with obesity. Socioeconomic status (SES) has been suggested to be associated with obesity and obesity related diseases. This study aimed to evaluate the time trend in socioeconomic inequality in obesity-related mortality over the last decade in Korean population. We evaluated the influence of education level, as an indicator of SES, on obesity-related mortality using death data from the Cause of Death Statistics and the Korean Population and Housing Census databases. The rate ratio of the mortality of people at the lowest education level as compared with those at the highest education level (relative index of inequality [RII]) was estimated using Poisson regression analysis. Between 2001 and 2011, RII (95% confidence interval) for overall obesity-related disease mortality increased from 2.10 (2.02-2.19) to 6.50 (6.19-6.82) in men, and from 1.94 (1.79-2.10) to 3.25 (3.05-3.45) in women, respectively. Cause-specifically, the same trend in RII was found for cardiovascular mortality and mortality from diabetes mellitus, whereas the RII of mortality from obesity-related cancers in men did not show the similar trend. Subgroup analysis stratified by age revealed that the RII of obesity-related mortality was much higher in younger people than in older people. In conclusion, there has been persistent socioeconomic inequality in obesity-related mortality in Korea, which was more evident in younger people than in older people and has been deepened over the last decade especially for cardiovascular disease and diabetes.