Psychological and physiological correlates of insulin resistance at fasting and in response to a meal in African Americans and Whites.

ABSTRACT

BACKGROUND: African Americans are more insulin resistant than are Whites. The purpose of this study was to characterize physiologic and psychological (stress coping style) correlates of insulin resistance in African Americans and Whites. METHODS: We examined African American (n = 67) and White (n = 41) men and women aged 18-45 years with body mass index 18-35 kg/m2. We used the homeostasis model assessment (HOMA-IR) and area under the curve for insulin (AUC) after a standardized meal as measure of insulin resistance. We obtained anthropometric measures and determined maximal aerobic power (VO(2max)) by treadmill exercise. We used stress profile to assess stress and coping style. RESULTS: Postprandial insulin AUCs were higher in African Americans than in Whites. Anthropometric measures and VO(2max)) were related to HOMA-IR and AUC. Although self-reported stress level did not differ between Whites and African Americans, positive appraisal predicted reduced HOMA-IR and negative appraisal coping style predicted increased insulin AUC. CONCLUSIONS: Psychosocial factors may be determinants of health and targets of intervention for obesity-related disorders such as insulin resistance. Existing behavioral intervention programs, designed with a sole emphasis on exercise and nutrition, may fall short of optimal effectiveness.