ESPE Abstracts

Background: In several studies it has been shown that BMI influences the timing of puberty, mostly in girls, but has not been a consistent finding in boys.

Objective and hypotheses: To investigate the association between BMI and timing of pubertal onset in a population based sample of Turkish boys.

Method: Data on growth and pubertal development were collected by biannual visits to six primary and secondary level schools in Istanbul city. Of a total of 2016 boys, data of 1208 boys aged from 8 to 18 years evaluated. Over time, measurements were repeated on these same children, but other children were also included in the study to provide adequate numbers for the older age groups. Our sample consists of a mixture of children followed longitudinally over different periods of time. Measurement of testicular volume (TV) using a Prader orchidometer, was performed by one observer (RB) throughout the study. Evaluation of pubertal stages was also done at 6 monthly intervals. Attainment of a testicular volume of 4 ml was accepted as the onset of puberty. The data were entered in a FoxBase program and analyzed by using SPSS-PC.

Results: The results of only the longitudinally followed children are given here. In this subsample of 227 boys, who were followed longitudinally, age at onset of puberty was 10.9±1.0 (9–13.8) years. Mean BMI-SDS was 0.09±1.2 during prepubertal time before the onset of puberty and mean BMI-SDS at onset of puberty was 0.02±1.3, significantly lower than the prepubertal period (P=0.0001). In this subsample of boys the mean delta BMI-SDS was −0.07 from the time testes volume 2 ml to the time of testes volume 4 ml.

Conclusions: The onset of puberty is associated with a lower BMI in healthy boys.