Statistics
Statistical analysis were performed with GraphPad Prism 6.01. Results are expressed as mean ± SEM. Variables were checked for normality using the Kolmogorov–Smirnov test prior to analyses. Comparisons within groups were performed using paired t-test. For between groups differences, unpaired t-test or Man-Whitney U test were used for normally distributed or nonparametric variables, respectively.Correlation analysis was used to study the associations between follistatin concentrations and auxological, endocrine-metabolic, and body composition parameters. Three outliers were identified by the interquartile range method; correlations are presented for n=69 out of 72 girls. The level of significance was set at p< 0.05.