Objective: We examined the relationship between income and education level with BMI and waist circumference to provide further understanding of the relationship between socioeconomic status and obesity and to identify the presence of sex differences.
Research methods and procedures: A total of 7962 people >or=20 years of age (3597 men; 4365 women) who participated in the 1998 Korean National Health and Nutrition Examination Survey provided data including height, weight, waist circumference, education, and income level. We examined adjusted BMI and waist circumference according to level of income and education and the association between income and education with obesity and abdominal obesity by multiple logistic regression analysis.
Results: In men, significant dose-response relationships were noted between income and obesity (trend, p < 0.05) and abdominal obesity (trend, p < 0.05). Compared with the lowest income group, the adjusted odds ratios (ORs) (95% confidence interval) of the highest income group for obesity and abdominal obesity were 1.65 (1.18 to 2.32) and 1.37 (0.94 to 1.98), respectively. However, income was not associated with obesity or abdominal obesity in the fully adjusted models in women. With regard to education, women showed significantly decreased ORs, with inverse trends for obesity and abdominal obesity across all education levels. Compared with the lowest education group, the adjusted ORs (95% confidence interval) for obesity and abdominal obesity were 0.66 (0.57 to 0.76) and 0.40 (0.35 to 0.45), respectively, among women with 7 to 12 years of schooling and 0.27 (0.21 to 0.34) and 0.15 (0.12 to 0.18), respectively, among women with 13 or more years of schooling.
Discussion: Socioeconomic difference has a considerable impact on the prevalence of obesity among the Korean population, and the patterns differ substantially across sex.