Bisphenol A (BPA) Exposure and Risk of Idiopathic Central Precocious Puberty (ICPP) among School-aged Girls in Shanghai, China

Background: It is supposed that exposure to Bisphenol A (BPA) may increase the risk of precocious puberty (PP) in girls. However, few studies have investigated the relationship between urinary BPA levels and idiopathic central precocious puberty (ICPP) in school-aged girls in China.

Objective: We investigated total BPA concentration in subjects` urine and examined the correlation with ICPP in school-age girls in Shanghai.

Methods: We conducted a 1:1 matched case-control study of ICPP among school-aged girls in Shanghai. The study included 136 girls diagnosed with ICPP aged 6-9 years and 136 healthy girls matched for age. Total urinary BPA concentrations were determined for all subjects. Medical information of ICPP girls was recorded.

Results: BPA was detected in 83.8% of urine samples in ICPP group, which was significantly higher than the control group with a percentage of 58.8% (Χ²=16.02, p=0.000). Median levels of urinary adjust-BPA in ICPP group and control group were 6.35 and 1.17µg/g creatinine, respectively (Z=-6.345, p=0.000). After adjustment for confounders, compared with those in the lower quartiles of adjust-BPA, the higher quartiles were associated with a 1.47-fold increased risk of ICPP [Odds ratio (OR) =1.47, 95% confidence interval (CI): 1.22-1.77, p=0.000]. In the ICPP group, weak negative correlations were presented between urinary adjust-BPA levels and basal FSH levels (r=-0.236, p=0.006) and peak FSH levels (r=-172, p=0.045).

Conclusion: The present findings suggest that BPA exposure may be associated with an elevated risk of ICPP in girls. The mechanism may be related to the relatively lower levels of FSH.