Educational disparities in the metabolic syndrome in a rapidly changing society - the case of South Korea

Background Most of the evidence about socioeconomic inequalities in the metabolic syndrome comes from Western industrialized societies. The aim of this study is to examine how the inequalities appear and what could explain them in Korea, a rapidly changing society. Methods We analysed the nationwide survey data of 1998 and 2001 with a sample of 4630 men and 5896 women (>= 25 years). The subjects were grouped into four birth cohorts based on the historical context: born before 1946, 1946-53, 1954-62, and since 1963. Socioeconomic position was defined by education level: high school graduation or above as the more educated group, and below that as the less educated one. The syndrome was defined according to ATP III criteria using abdominal obesity for Asians. The covariates included family history of diabetes, smoking, drinking, daily physical activity, regular exercise, suicidal ideation, weight change, and carbohydrates intake. The associations were examined by stratified logistic regression models across cohorts and gender. Results Less-educated women had higher prevalence with widening gaps across successive cohorts; the age-adjusted odds ratios of the less-educated group were 1.22 (0.86-1.71), 1.41 (1.01-1.97), 2.50 (1.87-3.35), and 2.64 (1.69-4.14). They hardly changed after covariate adjustment, and remained significant with considerable attenuation after controlling body mass index. However, educational disparities were not observed in men. Conclusions We could observe the complex pattern of disparities in the metabolic syndrome across cohorts and gender. An equity-sensitive health promotion programme to prevent further spread of social inequalities may have beneficial effects on the metabolic syndrome and its components in Korea.