Major Depressive Disorder and Insulin Resistance in Nondiabetic Young Adults in the United States: The National Health and Nutrition Examination Survey, 1999-2002

OBJECTIVE: The association between depression and insulin resistance has been evaluated in previous studies with conflicting results. This study aimed to explore the relationship between major depressive disorder (MDD) and insulin resistance among nondiabetic young adult men and women in the United States. METHOD: Analyses of cross-sectional data from the National Health and Nutrition Examination Survey (NHANES), 1999-2002, were conducted. The nationally representative sample consisted of 279 men and 358 women aged 20-39 years. MDD was determined by the WHO Composite International Diagnostic Interview (CIDI). Insulin resistance was measured by the homeostasis model assessment for insulin resistance. RESULTS: Of 637 subjects, 16 men and 18 women had MDD (weighted percentage = 6.6%, SE = 1.2). Using logistic regression, no significant association was found between MDD and insulin resistance among the nondiabetic young adults in bivariate analysis (β = -0.01, OR = 0.99, 95% CI = [0.38, 2.57], p = .98). A significant interaction effect between gender and MDD was observed. For men, MDD was negatively associated with insulin resistance after adjusting for age, race/ethnicity, waist circumference, smoking status, systolic blood pressure and triglyceride level (β = -2.12, OR = 0.12, 95% CI = [0.02, 0.62], p = .01). No significant association between MDD and insulin resistance among women was found (β = 0.61, OR = 1.84, 95% CI = [0.47, 7.14], p = .38). CONCLUSIONS: Overall findings suggest there is no significant association between MDD and insulin resistance among nondiabetic young adults aged 20-39 years. However, gender differences in this relationship were noted.