MAJOR DEPRESSION AND INSULIN RESISTANCE AMONG NONDIABETIC U.S. ADULTS AGED 20-39 YEARS: THE ROLES OF GENDER AND RACE/ETHNICITY

Abstract

The relationship between depression and insulin resistance has been evaluated in previous studies but with conflicting results. No study was found that investigates the role of race/ethnicity in the relationship between depression and insulin resistance. The purpose of this study was to: 1) determine the prevalence of major depression and insulin resistance among nondiabetic young adults aged 20-39 years in the United States, 2) examine the relationship between major depression and insulin resistance among nondiabetic young adults aged 20-39 years in the United States, and 3) determine whether this relationship varies by gender, race/ethnicity, or measure of depression. Analyses of cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) 1999-2008 were performed. The study sample consisted of 1,054 (46.5%) men and 1,211 (53.5%) women who were nondiabetic and aged 20-39 years (N = 2,265). Major depression was measured by the Composite International Diagnostic Interview in NHANES 1999-2004 and by the Patient Health Questionnaire-9 in NHANES 2005-2008. Insulin resistance was measured by the homeostasis model assessment for insulin resistance. The prevalence of major depression and insulin resistance among nondiabetic U.S. adults aged 20-39 years in the study was 3.7% (n = 84; weighted % = 3.8) and 25.7% (n = 582; weighted % = 22.7) respectively. No significant association was found between major depression and insulin resistance in bivariate logistic regression analysis. However, a significant interaction effect between gender and major depression was observed. For men, major depression was negatively associated with insulin resistance after adjusting for age, race/ethnicity, systolic blood pressure, triglyceride level, high-sensitivity C-reactive protein, obesity, leisure time physical activity, smoking, and alcohol consumption. In contrast, no significant association between major depression and insulin resistance among women was found. There was no significant interaction between race/ethnicity and major depression. No significant variations in the relationship between major depression and insulin resistance by measure of depression were revealed. Study findings provide support for a significant positive relationship between insulin resistance and 1) systolic blood pressure, 2) triglyceride level, 3) and obesity as measured by body mass index or waist circumference among nondiabetic young adults aged 20-39 years.