BACKGROUND: Previous studies have examined the relationship between leptin,body mass, and pubertal status. The present study directly compares the relationship of leptin and estradiolin 5 groups of girls with different combinations of pubertal status and weight. MATERIAL/METHODS: Westudied girls with idiopathic precocious puberty, age-matched non-obese prepubertal girls, age-matchedobese prepubertal girls, normal pubertal girls, and obese pubertal girls (n=12/group). RESULTS: Leptinlevels were significantly higher in obese pubertal girls (26.6+/-8.4 ng/mL) than in all others. Leptinlevels were significantly higher in obese prepubertal girls (20.7+/-10.9 ng/mL) (mean+/-SD) comparedto girls with precocious puberty (7.7±5.4 ng/mL, p<0.004), non-obese prepubertal girls (5.55±3.6 ng/mL, p<0.001), and normal pubertal girls (4.8±2.9 ng/mL, p<0.001). Leptin level did not correlate significantly with estradiol level. Leptin-SDS (standard deviation score), which corrects leptin level for gender, pubertal stage, and BMI, was significantly lower in the obese pubertal group than in the 3 non-obese groups.
Conclusions: These findings confirm previous studies that body mass, chronological age and pubertal stage are determinants of leptin level. However, these are not the only factors determining leptin
level as evidenced by persistent differences in leptin level between obese and non-obese pubertal girls even when correcting for pubertal stage and BMI. While the present study provides no new answers to the question of pubertal regulation, it provides a direct comparison of combinations of weight, pubertal stage, and leptin level, as background for future studies.

Keywords: Body Mass Index, Body Weight, Case-Control Studies, Child, Leptin, Obesity, Puberty, Puberty, Precocious