Factors associated with glucose and insulin levels in wealthy postmenopausal women

OBJECTIVE - Little is known about the covariates of hyperglycemia and hyperinsulinemia. We examined candidate factors in postmenopausal women. RESEARCH DESIGN AND METHODS - We determined the cross-sectional associations of sociodemographic, body size, lifestyle, reproductive, and menopausal factors with pre-trial fasting and postchallenge glucose and insulin levels in 869 postmenopausal women aged 45-65 years. Women were participants in the Postmenopausal Estrogen/Progestin Interventions study who were not taking estrogen or insulin. RESULTS - Plasma glucose levels increased significantly with age; serum insulin levels did not. BMI and waist-to-hip ratio (WHR) each showed graded positive and independent associations with glucose and insulin levels. Alcohol intake, cigarette smoking, physical activity, parity, education, and income were also associated with insulin or glucose in age-adjusted models. In multivariable models, BMI and WHR explained 18% of the variability in fasting glucose, 16% in postchallenge glucose, 28% in fasting insulin, and 17% in postchallenge insulin. Age and all other factors combined accounted for <6% of the variance in glucose or insulin. In multiply adjusted models, African-American and Hispanic women had higher fasting and 2-h insulin levels than non-Hispanic white women. CONCLUSIONS - Most of the variance in glycemia and insulin is unexplained. Measures of obesity and fat distribution account for nearly all the explained variance.