Role of fat cell size for plasma leptin in a large population based sample.

Earlier studies suggest that fat mass is the only important factor predicting the circulating leptin level in humans. In this population based cross sectional study on 447 women and 158 men total fasting plasma leptin was related to adipose tissue mass and fat cell size to investigate the importance of adipose tissue cellularity. An abdominal subcutaneous fat biopsy was obtained and mean fat cell volume and mean fat cell weight and size were determined. Fasting serum Leptin and Leptin secretion in vitro was also measured. Body fat mass was measured by bioimpedance. Adipose tissue mass and fat cell size independently associated with leptin levels. Partial correlation coefficients were 0.6 (p<0.001) and 0.3 (p<0.01) for fat mass and fat cell size, respectively. Together they explained 2/3 of leptin variance (i. e., adjusted r (2)). Fat mass was a stronger regressor than fat cell volume. The relationship was independent of age, gender and adipocyte secretion of leptin (the latter determined in a subgroup of 391 individuals). In conclusion, although total fat mass is the strongest predictor of circulating leptin, adipose tissue cellularity play an additional independent and important role.