Serum leptin levels and adiposity in adult Chinese: a preliminary observation

Objective To establish normal serum leptin levels in Chinese and investigat e the relationship between serum leptin levels and body fat, gender, age an d androgen. Methods Serum leptin levels were measured in 77 lean (BMI < 25) and 28 overweight or obese (BMI greater than or equal to 25) subjects by a radioimmunoassay (RIA) method. Results The serum leptin levels in lean Chinese were 2.15 +/- 1.46 ng/ml in male and 7.85 +/- 3.60 ng/ml in female, which are similar to those of Cauc asians, while in overweight or obese ones, the levels were 4.87 +/- 3.47 ng /ml and 16.59 +/- 6.92 ng/ml respectively, lower than those in Caucasians. A 2 -3 times higher leptin concentrations were found in women than in men i n both conditions. Even when the number of lean males was expanded to 79 su bjects aged from 17 - 80 years, no significant leptin-age relationship was found. Despite 25% of obese subjects manifested a relative deficiency of le ptin, as a whole, leptin levels in both men and women were significantly co rrelated with BMI (r = 0.69, P < 0.001 in male and r = 0.63, P < 0.001 in f emale). Conclusions Serum leptin levels in Chinese lean people are similar to those in Caucasians and in both lean and obese groups, the leptin levels are cor related with BMI, suggesting that the great majority of the obese patients are resistant to endogenous leptin. Those who are relatively deficient of l eptin may become a group of good candidates for leptin treatment in the fut ure.