Objective: Prior studies have reported ethnic differences in adiponectin and ghrelin, but few have assessed the role of body size in normoglycemic women. We compared fasting adiponectin and ghrelin concentrations in normoglycemic 40- to 80-year-old Filipino, African-American, and white women.
Methods: Participants included women from the Rancho Bernardo Study (n = 143), the University of California-San Diego Filipino Women's Health Study (n = 136), and the Health Assessment Study of African-American Women (n = 212). A 2-hour oral glucose tolerance test was administered; glucose, insulin, lipid, and anthropometric measurements were obtained. Fasting adiponectin and ghrelin were measured by radioimmunoassay.
Results: Whites and Filipinas had similar BMI (23.7 and 24.3 kg/m(2), respectively), waist girth (75.6 and 77.2 cm, respectively), and total body fat (27.4 and 28.5%, respectively); African-Americans had significantly larger BMI (28.8 kg/m(2)), waist girth (86.3 cm), and body fat (39.6%, p < 0.0001). Adiponectin was lower in Filipinas (8.90 mug/mL) and African-Americans (9.67 mug/mL) compared with whites (15.6 mug/mL, p < 0.001) after adjusting for age, homeostasis model assessment of insulin resistance (HOMA-IR), and waist-to-hip ratio. Compared with whites, Filipinas (beta = -5.06, p < 0.0001) and African-Americans (beta = -6.85, p < 0.0001) had significantly lower adiponectin levels after adjusting for age, waist-to-hip ratio, HOMA-IR, triglycerides, high-density lipoprotein (HDL) cholesterol, exercise, and alcohol use. Ghrelin was significantly lower in Filipinas compared with African-Americans (1146.9 vs. 1412.2 pg/mL, p < 0.001), and this observation persisted in multivariable analysis (beta = -245.4, p < 0.0001). Ghrelin levels did not differ between whites (1356.9 pg/mL) and either ethnic group.
Discussion: Normoglycemic Filipino and African-American women had significantly lower adiponectin concentrations than white women, and Filipinas had lower ghrelin levels than African-Americans, independently of body size or indices of insulin resistance or lipids.