Serum irisin levels increase in girls with central precocious puberty not dependent on BMI: a pilot study

OBJECTIVE: The objective of this study is to investigate the role of serum irisin level in diagnosis of central precocious puberty (CPP) in girls and its major determinants. METHODS: This study was conducted in 67 girls with CPP, 19 girls with premature thelarche (PT) and 59 normal controls. The major determinants of irisin were assessed by multivariate linear regression (MLR) analysis. Propensity score matching (PSM) analysis was performed to minimize the bias that can result from BMI. A receiver operating characteristic curve was used to obtain the optimal threshold value of irisin. RESULTS: The girls with CPP and PT had higher irisin levels than controls (P < 0.05). The optimal cutoff value of irisin levels for predicting CPP was 91.88 ng/mL, with a sensitivity of 70.1% and a specificity of 72.9%. MLR analysis showed that BMI was a predictor of irisin (P < 0.05). Serum irisin levels remained higher in the CPP girls than the controls with adjustment for BMI (P < 0.05). CONCLUSIONS: Increased serum irisin levels with CPP suggest that irisin is involved in puberty. However, due to low sensitivity and specificity, irisin level can only be used as an auxiliary indicator rather than a single diagnostic indicator of CPP.