INSULIN-RESPONSE IN A TRIETHNIC POPULATION - EFFECTS OF SEX, ETHNIC-ORIGIN, AND BODY-FAT - THE MIAMI COMMUNITY-HEALTH STUDY

OBJECTIVE - To assess sex and ethnic differences in hyperinsulinemia/i nsulin resistance and to examine the impact of percent body fat on suc h differences. RESEARCH DESIGN AND METHODS - A cross-sectional epidemi ological study was performed in a normoglycemic population of African- Americans (n = 159), Cuban Americans (n = 128), and non-Hispanic white s (n = 207) who resided in Dade County, Florida, from 1990 to 1995. Th e insulin area under the curve (AUC) in response to a standard 75-g or al glucose tolerance test (OGTT) was used as an indicator of hyperinsu linemia/insulin resistance. Analysis of covariance was performed to co mpare sex and ethnic differences in the insulin AUC. Multiple linear r egression was used to evaluate the independent correlates of the insul in AUC. RESULTS - After covariate adjustment for percent body fat, men displayed a significantly higher insulin AUC than did women (P < 0.00 1). African-Americans and Cuban-Americans each had a significantly hig her insulin AUC than did non-Hispanic white participants (P = 0.01). A lcohol consumption was inversely related to AUC (P = 0.04). CONCLUSION S - Despite the greater percentage of body fat in women, the insulin A UC was similar in women and men. After adjustment for the sex differen ce in percent body fat, women displayed a lower insulin AUC than did m en, indicating enhanced insulin sensitivity These differences by sex a nd ethnicity in insulin resistance are consistent with established dif ferences in heart-disease risk (i.e., higher in men and African-Americ ans) and suggest that hyperinsulinemia/insulin resistance may partly u nderlie such differences.