Leptin concentrations in the United States: relations with demographic and anthropometric measures.

BACKGROUND Leptin is a peptide that is strongly correlated with adiposity and is a potential determinant of obesity and its complications. OBJECTIVE Leptin concentrations from a representative sample of the US population were examined in relation to demographic and anthropometric measures. DESIGN Fasting serum leptin concentrations were measured in 6303 women and men aged > or =20 y in the third National Health and Nutrition Examination Survey. Anthropometric measures included body mass index, 4 skinfold thicknesses, and 4 body circumferences. Ethnic groups included non-Hispanic whites and blacks and Mexican Americans. RESULTS The mean serum leptin concentration was much higher in women (12.7 microg/L) than in men (4.6 microg/L). In a multivariate analysis, leptin concentrations were associated with the sum of 4 skinfold thicknesses, waist and hip circumferences, ethnicity, and age. These measures explained most of the variance in leptin concentrations in women (R2 = 0.69) and in men (R2 = 0.67). Triceps skinfold thickness, when substituted for the sum of skinfold thicknesses, performed nearly as well in women (R2 = 0.68) and men (R2 = 0.67). Leptin concentrations were slightly but significantly higher in non-Hispanic blacks than in non-Hispanic whites of both sexes when these anthropometric measures and age were controlled for; Mexican Americans had concentrations that were intermediate compared with the concentrations of non-Hispanic whites and blacks. CONCLUSIONS In this large, representative sample of the US population, demographic and anthropometric measures predicted serum leptin concentrations in women and men.