Sex differences in the association between socio-economic status and type 2 diabetes: Data from the 2005 Korean National Health and Nutritional Examination Survey (KNHANES)

Objectives: While socio-economic status (SES) is considered a key social-environment factor affecting health outcomes, sex differences in the association between SES and the risk of type 2 diabetes remain unclear. The aims of this study were: (1) to identify risk factors associated with type 2 diabetes in a representative sample of Korean adults with a focus on socio-economic determinants; and (2) to examine how the association between SES and type 2 diabetes is affected by sex. Study design: Cross-sectional study. Methods: This study used data obtained from 3870 Korean adults (age ≥35 years) who participated in the 2005 Korean National Health and Nutritional Examination Survey (KNHANES III). The risk of type 2 diabetes in relation to SES was calculated, after controlling for other risk factors such as medical characteristics (hypertension, family history, body mass index, triglyceride, total cholesterol, high-density lipoprotein cholesterol), lifestyle factors (body mass index, smoking, alcohol intake, exercise) and perceived stress. Odds ratios (ORs) were calculated separately for Korean men and women using multivariate logistic regression. Results: Compared with individuals with ≥13 years of education, those with ≤6 years of education or 7-12 years of education had higher ORs for the risk of type 2 diabetes - 2.10 (95% confidence interval (CI) 1.27-3.48) and 1.62 (95% CI 1.04-2.52), respectively - after adjusting for age, sex, medical characteristics, lifestyle factors and stress level. The OR for women with ≤6 years of education was particularly high (OR 10.16, 95% CI 2.08-49.53), even after adjusting for the study covariates. However, this increasing trend in the OR was not observed for men. Conclusions: SES significantly influences the risk of type 2 diabetes in Korean adults, and there are interactions with sex. Korean women with a low level of education represent a particularly high-risk group for type 2 diabetes. Future interventions should incorporate more targeted diabetes prevention efforts for women with a low level of education.