Gender differences in relation to leptin concentration and insulin sensitivity in nondiabetic Chinese subjects

OBJECTIVE: To investigate the relationship between fasting plasma leptin co ncentrations and insulin resistance in Chinese men and women. DESIGN: Cross-sectional study design. SUBJECTS: Ninety-six nondiabetic Chinese (51 men and 45 Mt omen) with body mass index (BMI) between 18.4-35.8 kg/m(2) were studied. MEASUREMENTS: Plasma glucose and insulin concentrations were measured every 30 min for 2h after a 75 g oral glucose load. The degree of insulin resist ance was assessed using a modified insulin suppression test. Plasma leptin values were determined by radioimmunoassay. RESULTS: Pasting plasma glucose, glucose areas, fasting insulin, insulin ar eas, most of the lipoprotein concentrations and steady state plasma glucose (SSPG) concentrations were relatively similar between men and women. Despi te the fact that men had higher BMI values (26.1 +/- 0.5 vs 24.7 +/- 0.5 kg /m(2), P<0.05), fasting plasma leptin concentrations were significantly low er in men than in women (4.9 +/- 0.5 vs 9.0 +/- 0.8 ng/ml, P<0.001). Eastin g leptin values were positively related to SSPG concentrations by simple co rrelation analysis in both sexes. However, this relationship persisted in m en (r=0.513, P<0.01) but not in women (r=0.119, P=NS) after adjustment for BMI. Multiple regression analysis showed that SSPG concentrations, BMI, glu cose and insulin responses together accounted for 62.5% and 52.2% of the va riation in plasma leptin concentrations in Chinese men and women respective ly. CONCLUSION: Easting plasma leptin concentrations were lower in Chinese men than in Chinese women despite the higher BMI observed in men. After adjustm ent for BMI, plasma leptin values correlated with the degree of insulin res istance in men but not in women.