General and abdominal obesity in South Korea, 1998-2007: gender and socioeconomic differences

To examine national trends in prevalence and socioeconomic inequalities in both general (measured by body mass index) and abdominal obesity (measured by waist circumference) by gender and socioeconomic position (SEP) indicators.

Data were from four rounds of nationally representative cross-sectional surveys for Korean men and women aged 25-64 (6,286 in 1998, 4,839 in 2001, 4,181 in 2005, and 2,006 in 2007). We calculated age-adjusted prevalence rates of overweight and abdominal obesity by gender and SEP indicators (education, occupational class, employment status and income) and examined trends of prevalence and its inequalities.

Overweight and abdominal obesity has significantly increased in Korean men (P for linear trend <0.01), not in women. For men, high SEP was associated with overweight and abdominal obesity, but the magnitude of socioeconomic differences in obesity measures generally remained unchanged during the study period. Among women, low SEP was associated with overweight. Interestingly, increasing inequalities in abdominal obesity according to education and income were found in women.

Clear gender differences were noted in (1) time trends of overweight and abdominal obesity, (2) relationships between the obesity measures and various SEP indicators, and (3) linear time trends of socioeconomic differentials in obesity.