Influence of leptin on changes in body fat during growth in African American and white children.
OBJECTIVE
The aim of this study was to determine whether initial levels or temporal changes in fasting leptin were associated with longitudinal changes in body-fat mass in children.


METHODS
The study group consisted of 85 children (42 white and 43 African American) with a mean initial age of 8.1 +/- 0.1 years. The children had between three and six annual visits for repeated measurements of body composition by DXA and fasting leptin level. Fat mass and fasting leptin level were not normally distributed and were log-transformed. Data were analyzed using SAS Proc mixed growth models, with log fat as the dependent variable.


RESULTS
Initial leptin level was a significant predictor of the change in fat mass over time (p < 0.0001), with high initial leptin levels resulting in increased fat gain, independent of initial fat levels. This relationship remained significant when the data were analyzed separately by race (whites, p < 0.0001; African Americans, p = 0.008). The relationship between the initial level of leptin and the change in fat mass was not modified by race, sex, or Tanner Stage. The rate of change in leptin during the study was significantly related to the rate of change in fat mass in African Americans (p = 0.008) but not in whites (p = 0.490).


CONCLUSIONS
In conclusion, high fasting leptin level at the start of the study was significantly associated with increasing fat mass in this cohort, indicating that the children may be developing resistance to the effects of leptin.
Johnson
M S
MS
Institute for Health Promotion and Disease Prevention Research, Department of Preventive Medicine, University of Southern California, Los Angeles, California 90033, USA.
Huang
T T
TT
Figueroa-Colon
R
R
Dwyer
J H
JH
Goran
M I
MI
D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000254:growth & development*; D044383:Black People; D001823:Body Composition; D002648:Child; D015331:Cohort Studies; D005215:Fasting; D005260:Female; D006801:Humans; D020738:Leptin / Q000097:blood* / Q000235:genetics; D008137:Longitudinal Studies; D008297:Male; D009765:Obesity / Q000097:blood* / Q000208:ethnology / Q000209:etiology / Q000235:genetics; D012741:Sexual Maturation / Q000502:physiology; D044465:White People; D001741:Black or African American
D020738:Leptin