Serum leptin levels during childhood and adolescence: relationship with age, sex, adiposity and puberty.

We studied serum leptin levels in 189 healthy children to evaluate related factors during childhood and adolescence. Leptin correlated with body mass index (BMI), triceps skinfold thickness (p<0.001) and body weight (p<0.01). Obese children and girls had higher leptin levels than non-obese children and boys, respectively (p<0.001). In girls, leptin correlated positively with age, skinfold thickness and BMI (p<0.001). In boys, leptin correlated negatively with age (p<0.001) and positively with skinfold thickness (p<0.05). Prepubertal boys had higher leptin levels than prepubertal girls and pubertal boys (p<0.05). Pubertal girls had higher leptin levels than prepubertal girls and pubertal boys (p<0.001). Leptin levels in girls were higher at Tanner stages 4 and 5 than at stage 1 (p<0.001). In conclusion, serum leptin levels are related with adiposity, have obviously age-related gender differences during childhood and adolescence, and may be involved in the maturation of reproductive capacity.