ESPE Abstracts

Objective Recent studies suggest that boys are undergoing puberty at a younger age. Further, the number of idiopathic male central precocious puberty (CPP) cases are increasing over time. Only a few studies have evaluated the etiological factors in boys with CPP. We describe the etiology of CPP. Further, we define key auxological and clinical cues indicative of organic CPP (OCPP) and characterize the incidence of CPP.

Methods We reviewed the medical records of 43 boys who had been diagnosed with CPP at the Helsinki University Hospital between 1985 and 2014. Patients were categorized into two subgroups based on the imaging findings: idiopathic CPP (ICPP) (n=32) and OCPP (n=11).

Results Patients with OCPP were diagnosed younger (median 8.1 years) than patients with ICPP (median 10.3 years) (P=0.006). At diagnosis, there were no differences in the Tanner genital (P=0.65) or pubic hair stages (P=0.50). Though basal serum testosterone levels were higher in OCPP than ICPP (medians 15.0 and 4.8 nmol/l respectively, P=0.038), basal FSH (P=0.78) and basal or stimulated LH (P=0.22 and P=0.19, respectively) did not differ significantly between groups. At diagnosis, patients with OCPP were shorter (mean 0.5SD) than patients with ICPP (1.8SD) (P=0.003). Further, BMI, height velocity, measures related to bone age, or predicted adult height did not differ between the two groups (all, P=0.19-0.74). Multivariate regression with height SDS (HSDS) and age at diagnosis differentiated between OCPP and ICPP with good overall performance, AUC 0.84, P<0.001. With the addition of basal laboratory values (serum testosterone and FSH, both P<0.05), the performance was excellent AUC 0.97, P<0.001. Between 2010-2014, the annual incidence of CPP in boys was 3.7 per 100000 (95%CI 1.2-11.8 per 100000). A significant increase in incidence between 1990-2014 was evident in ICPP (P<0.001), whereas the incidence of OCPP appeared constant (P=0.45). The corresponding incidence rate ratios (IRR) were 1.11 (95%CI 1.05 to 1.19) in ICPP and 1.03 (95%CI 0.95 to 1.14) in OCPP.

Conclusions In boys, age, HSDS, and serum testosterone values differentiated between OCPP and ICPP. Our analysis suggests that these cues, supplemented with serum FSH, showed good to excellent performance, and could be utilized in the diagnostic decision-making. The incidence of CPP was approximately 3.7 per 100000. The incidence of ICPP increased approximately 11% annually between 1990-2014, whereas the incidence of OCPP appeared constant. The increase in the incidence of ICPP seems too high to be explained only by secular trend.