Ethnic Differences in Insulin Sensitivity and β-Cell Function in Premenopausal or Early Perimenopausal Women Without Diabetes

Abstract

OBJECTIVE—To assess differences in insulin sensitivity and β-cell function between nondiabetic premenopausal or early perimenopausal non-Hispanic white women and African American, Chinese American, Japanese American, and non–Mexican-American Latino women. RESEARCH DESIGN AND METHODS—Homeostasis model assessments (HOMAs) of insulin sensitivity (HOMA%S) and β-cell function (HOMA%β) were used. Stepwise multivariable ethnic-specific ANCOVA models were used to compare HOMA%S and HOMA%β between non-Hispanic whites and each of the four ethnic groups. RESULTS—HOMA%S was lower in African Americans, Chinese Americans, and Japanese Americans when compared with non-Hispanic white women after correcting for waist circumference, presence of impaired fasting glucose, and site. Significant differences persisted only between African Americans and non-Hispanic whites after inclusion of triglycerides in the model. Triglycerides indirectly corrected for the differences in HOMA%S in the other two groups. There were no differences in HOMA%S between the non–Mexican-American Latinos and the non-Hispanic whites. Japanese Americans and Chinese Americans had lower HOMA%β than non-Hispanic whites, whereas African Americans had higher HOMA%β than non-Hispanic whites after correcting for confounders. HOMA%β was similar between non–Mexican-American Latinos and non-Hispanic whites. CONCLUSIONS—These data suggest that type 2 diabetes prevention strategies for African-American women should initially target decreased insulin sensitivity, whereas strategies for Japanese-American and Chinese-American women may initially need to target both decreased insulin sensitivity and β-cell function. Previous studies of Mexican-American populations may not apply to non–Mexican-American Latino women.