Plasma adiponectin and leptin levels, body composition, and glucose utilization in adult women with wide ranges of age and obesity

OBJECTIVE - The purpose of this study was to determine the relationships between plasma adiponectin and leptin levels, total and central obesity, and glucose utilization across the adult age span. RESEARCH DESIGN AND METHODS - We studied 148 women aged 18-81 years with a BMI range of 17.2-44.3 kg/m ². Total percent body fat was determined by dual-energy X-ray absorptiometry and abdominal fat by computed tomography. Glucose tolerance in nontype 2 diabetic volunteers was determined with an oral glucose tolerance test. Glucose utilization (M) was measured during the last 60 min of hyperinsulinemic-euglycemic clamps (240 pmol · m^-2 · min^-1). Plasma adiponectin levels were measured by radioimmunoassay. The women were separated into three age-groups: young, middle, and old (<40, 40-59, and ≥60 years, respectively), as well as by glucose tolerance status. RESULTS - Adiponectin concentrations did not differ by age-groups. There were significant age effects for BMI, percent body fat, visceral fat, subcutaneous abdominal fat, VO_2max, and M. Adiponectin levels were lower in the prediabetic women (n = 18) than in the normal glucose-tolerant women (n = 108) and the women with type 2 diabetes (n = 22) (both P < 0.05). Univariate correlations revealed significant negative relationships between plasma adiponectin levels and BMI, percent body fat, visceral fat, subcutaneous abdominal fat, fasting leptin, and fasting insulin and positive relationship with M (all P < 0.05). In a multiple stepwise regression model to predict adiponectin, only M remained in the model at P < 0.001. Multivariate analyses revealed a significant relation for M as a function of adiponectin, insulin, and VO_2max. CONCLUSIONS - The data suggest that plasma adiponectin does not change with age but levels are negatively associated with percent body fat, visceral fat, subcutaneous abdominal fat, insulin, and leptin levels in women. Adiponectin is positively associated with M across the age span in women.