Leptin concentrations in the United States: relations with demographic andanthropometric 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 pop ulation were examined in relation to demographic and anthropometric measure s. Design: Fasting serum leptin concentrations were measured in 6303 women and men aged greater than or equal to 20 y in the third National Health and Nu trition Examination Survey. Anthropometric measures included body mass inde x, 4 skinfold thicknesses, and 4 body circumferences. Ethnic groups include d non-Hispanic whites and blacks and Mexican Americans. Results: The mean serum leptin concentration was much higher in women (12.7 mug/L) than in men (4.6 mug/L). In a multivariate analysis, leptin concent rations were associated with the sum of 4 skinfold thicknesses, waist and h ip circumferences, ethnicity, and age. These measures explained most of the variance in leptin concentrations in women (R-2 = 0.69) and in men (R-2 = 0.67). Triceps skinfold thickness, when substituted for the sum of skinfold thicknesses, performed nearly as well in women (R-2 = 0.68) and men (R-2 = 0.67). Leptin concentrations were slightly but significantly higher in non -Hispanic blacks than in non-Hispanic whites of both sexes when these anthr opometric measures and age were controlled for; Mexican Americans had conce ntrations that were intermediate compared with the concentrations of non-Hi spanic whites and blacks. Conclusions: In this large, representative sample of the US population, dem ographic and anthropometric measures predicted serum leptin concentrations in women and men.