Leptin in African-American children

Leptin, the protein product of the obesity gene, produced by adipose tissue, regulates body weight and energy expenditure through CNS feedback mechanisms. In obesity, leptin levels are elevated suggestive of leptin resistance. Because of increased prevalence of obesity in African-Americans, the aim of this study was to assess leptin and its relationship to adiposity in African-American children. We measured plasma leptin levels in 42 African- American children (23 M, 19 F), age 11.8 ± 0.3 yr, and compared them with 30 American-White children matched for age, body composition and puberty. Body composition was assessed by bioelectrical impedance and plasma leptin by RIA. Data are presented as means ± SEM and statistical significance is implied by p<0.05. There was no racial difference in plasma leptin levels (Blacks: 9.8 ± 1.6, Whites 9.8 ± 1.9 ng/ml). Leptin correlated with %BF in Black (r=0.75, p=0.005) and White (r=0.79, p=0.005) children. There were no gender or puberty related differences in leptin levels in African-American children. We concluded that leptin levels are comparable between African-American and American White children of similar body composition. The major determinant of serum leptin levels in these children is degree of adiposity with no gender or puberty related differences. Longitudinal studies are needed to assess leptin's role during puberty in both genders.