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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #77414
Title: SERUM LEPTIN LEVELS IN CHILDREN AND YOUNG ADULTS

Author
item Ellis, Kenneth
item NICOLSON, MARGERY

Submitted to: New England Journal of Medicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/27/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: We measured the amount of leptin, a protein secreted from fat tissue, in the blood of obese and normal-weight children 3-18 years of age and young adults 20-29 years of age, representing Caucasians, African-Americans and Hispanic-Americans. A recent study showed that adults who were obese (defined by a high body mass index) has much higher blood leptin levels than normal-weight adults, and the levels were correlated with the percentage of body fat; however, data on children are sparse. We wanted to determine, in our young subjects: (1) whether there was a relationship between leptin level and amount of body fat; (2) whether there was a difference in the leptin level of males vs. females; (3) whether the leptin level was affected by puberty and sexual development; (4) whether the level was affected by race. We found that: (1) the amount of leptin increased with amount of fat mass; (2) the females had higher leptin levels than males with the same amount of fat; (3) the leptin level was not changed by puberty; (4) the level was not affected by race. We were correct in theorizing that the blood leptin level is more reflective of the amount of fat of an individual (fat mass) than his relative fatness, meaning the percentage of fat in his total body weight. These facts will further scientific studies focusing on obesity, why some children are fatter than others, and what can be done about it, especially during growth and development.

Technical Abstract: Background. The serum concentration of leptin, a hormone secreted by adipocytes, is elevated in the extremely obese adult and child. It is unknown whether this increase is related to body fat or relative fatness per se, or whether this relationship is affected by gender, ethnicity, age, and/or stage of sexual development in children. Methods. We measured serum leptin levels in 183 children and 27 young adults using a double-antibody ELISA assay. Body fat mass (FM) and body fatness, expressed as a percentage of body weight (%Fat), were determined by dual-energy X-ray absorptiometry. Correlations for serum leptin with FM, %Fat, and body mass index (BMI) were examined. Analyses of covariance were used to determine the effects of gender, ethnicity, and sexual maturation (Tanner stage). Results. We found strong positive correlations (r=0.56-0.88, P <0.001), for serum leptin with FM, %Fat, and BMI which were egender-dependent (P<0.0001), and this difference remained significant (P<0.001) when leptin was normalized for FM. For each gender, the mean leptin/FM ratios were relatively invariant across Tanner stages; no differences were observed between the oldest children (Tanner 5) and the young adults. Conclusions. Girls have higher serum leptin concentrations than boys even when adjusted for fat mass and Tanner stage, suggesting that with increasing obesity, changes may occur in leptin synthesis, clearance rates, bioactivity, and/or leptin transport.