Differences and similarities regarding adiponectin investigated in African and Caucasian women

OBJECTIVE: Concentrations of adiponectin, an adipocytokine with insulin-sensitizing actions, may vary according to ethnic group. This study aimed to determine whether fasting adiponectin levels of Caucasian and African women differ. A second objective was to determine which components of the metabolic syndrome are more closely related to adiponectinemia in both groups. DESIGN: A cross-sectional study including 102 urban African and 115 Caucasian women with a wide range of obesity aged 20-55 years. METHODS: Anthropometric measurements were taken, namely weight, height, body mass index, waist circumference, and hip circumference. Cardiovascular measurements included blood pressure and arterial compliance. Fasting blood samples were taken to determine glucose, insulin, C-peptide, leptin, adiponectin, and lipid levels. RESULTS: Mean adiponectin levels of the whole groups did not differ, but normal weight African women (N = 38) showed marginally lower adiponectin levels than their Caucasian counterparts (N = 41; P = 0.047). No differences in adiponectin were shown for overweight and obese women. Separate multiple regression analyses for ethnic groups showed that only homeostasis model assessment-insulin resistance (HOMA-IR) significantly contributed to the variance in adiponectin levels of African women, whereas leptin, triacylglycerol levels and HOMA-IR contributed significantly to adiponectin variance in Caucasian women. An additional multiple regression analysis in a combined ethnic group (N = 217) showed ethnicity to be a significant contributor to variances in adiponectin levels. CONCLUSIONS: Even though adiponectin levels of these ethnic groups are similar, different associations of adiponectin with leptin and triacylglycerol levels might indicate that there are ethnic differences regarding the mechanistic functions of adiponectin within the scope of the metabolic syndrome.