Relationship of serum leptin to total and truncal body fat.

1. In this study we investigated the relationship between serum leptin levels and body fat distribution in a random sample of women of widely ranging age and body mass index. Anthropometry and dual energy X-ray absorptiometry were used to measure body fat and its distribution. 2. Leptin levels (log transformed) were not significantly correlated with age, but were significantly positively correlated (P < 0.001) with most anthropometric measures except waist-to-hip circumference ratio. The strongest correlations were with total grams of body fat and percentage body fat (r = 0.68 and 0.76 respectively, P < 0.001). When corrected for percentage body fat the partial correlation coefficients for all other measures became non-significant. The correlation with truncal body fat fell significantly from 0.66 to -0.05 after correction, but the partial correlation with total body fat remained significant (P < 0.005) when grams of truncal fat were controlled for (r = 0.21). 3. These results indicate that the relationship of serum leptin to percentage body fat is the strongest, and that truncal body fat, although the most metabolically active, does not appear to have an independent association with serum leptin.