Trends in socioeconomic inequalities in five major risk factors for cardiovascular disease in the Korean population: a cross-sectional study using data from the Korea National Health and Nutrition Examination Survey, 2001–2014

OBJECTIVES To examine trends in socioeconomic inequalities in major cardiovascular disease (CVD) risk factors among the Korean population. DESIGN Cross-sectional study. SETTING A nationally representative population survey database. PARTICIPANTS A total of 42 725 Koreans, aged 25-64 years, who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) II (2001) to VI (2013-2014). MAIN OUTCOME MEASURES Trends in socioeconomic inequalities in five major CVD risk factors (smoking, obesity, diabetes, hypertension and hypercholesterolaemia). RESULTS Gender differences were noted in the time trends in socioeconomic inequalities in smoking, obesity, diabetes and hypertension. Among men, low socioeconomic status (SES) was associated with higher prevalence of smoking, but not with obesity, diabetes or hypertension. The magnitudes of socioeconomic inequalities in smoking, obesity and diabetes remained unchanged, and the magnitude of the inequality in hypertension decreased over time. However, among women, low SES was associated with higher prevalence of smoking, obesity, diabetes and hypertension. Time trends towards increasing socioeconomic inequalities, measured by income, in smoking, obesity and diabetes were found in women. Unlike the other CVD risk factors, hypercholesterolaemia was not associated with socioeconomic inequality. CONCLUSIONS SES had a stronger impact on major CVD risk factors among Korean women than men. Moreover, socioeconomic inequalities in smoking, obesity and diabetes worsened among Korean women over time. Public policies to prevent smoking, obesity and diabetes in women with lower SES are needed to address inequalities.