Obesity Transition and Inequalities by Sociodemographic Factors in Korean Adults, 1998–2018

Abstract

ObjectivesTo investigate the obesity transition and inequalities by socio-demographic factors in Korea, we examined the nationwide overall and abdominal obesity trends and its association with socio-demographic factors in Korean adults (aged 19–79 years) in 1998–2018. MethodsIn the Korea National Health and Nutrition Examination Survey 1998–2018 (n = 85,262), we estimated the age-standardized prevalence of overall (body mass index [BMI)≥25kg/m2) and abdominal obesity (waist circumference [WC]≥90 cm) in men and ≥85cm in women) in each sociodemographic subgroup. Weight, height, and WC were measured by medical staff. Logistic regression was performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between obesity prevalence and sociodemographic factors after mutual adjustment for all sociodemographic factors under study. All analyses accounted for a complex survey design. ResultsDuring the study period, the prevalence of overall and abdominal obesity increased in men (24.8% to 42.4%; 20.1% to 32.1%; respectively) but only a small change was observed in women (26.5% to 26.0%; 22.7% to 20.9%; respectively). When stratified by sociodemographic groups, obesity prevalence similarly increased in all groups of men but, in women, the trends varied across groups. In women, income (2016–2018: OR = 0.66, 95% CI = 0.56–0.78 overall obesity; OR = 0.60, 95% CI = 0.51–0.71 abdominal obesity) and education (OR = 0.62, 95% CI = 0.54–0.72 overall obesity; OR = 0.58, 95% CI = 0.50–0.68 abdominal obesity) were inversely associated with obesity prevalence, and the gaps between the groups became wider and solidified since 2007. ConclusionsThis is the largest and the most recent study including the entire survey phases of the KNHANES data (I-VII). Our data suggest that the inequalities in obesity prevalence by sex (men higher than women) and by socioeconomic status (women in lower-socioeconomic group higher than women in higher-socioeconomic group) have increased over time. These findings indicate that targeted, customized preventive strategies are needed to prevent further increase in obesity and related disease burdens in Korea. Funding SourcesThis work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (2019R1G1A1004227 and 2019S1A3A2099973).