Testosterone and leptin in a group of Chinese with and without diabetes

Aim: Leptin levels in the overweight and differences between men and women may be confounded by sex hormones in obesity-related type 2 diabetes. We ca rried out a study of leptin and testosterone and the effect of diabetes on this relationship in 71 Chinese subjects (51 with type 2 diabetes and 20 he althy non-diabetics) of whom 32 were overweight (body mass index (b.m.i.) > 25.0 kg/m(2)). Methods and results: Leptin levels were similar in the diabetic (median 7.4 , interquartile range 4.2-10.6 ng ml(-1)) and non-diabetic (11.3 (6.0-16.3) ng ml(-1)) subjects. Testosterone and free testosterone in diabetics and n on-diabetics were similar for both gender. Regardless of diabetes status, t estosterone and its free form tend to increase in overweight women and decr ease in men. Leptin correlated with testosterone in women with diabetes (Pe arson correlation coefficient r = 0.495, p = 0.037) but not in diabetic men . Sixty-eight per cent of leptin variance was affected by b.m.i, insulin, s ex (female) and diabetes status in a regression model that excluded testost erone (total and free). However, testosterone and insulin were predictors o f leptin changes in the non-diabetic subjects. In diabetes, b.m.i., sex (fe male) and insulin remained as predictors of leptin changes. Conclusions: These results suggest that apart from body adiposity, testoste rone also influences leptin levels and that diabetes has a significant effe ct on this association.