Cord blood BPA and reproductive and thyroid hormone levels of neonates

Background: Bisphenol A (BPA) is widely used and BPA exposure is nearly ubiquitous in developed countries. While animal studies have indicated adverse health effects of prenatal BPA exposure including reproductive dysfunction and thyroid function disruption possibly in sex-specific manner, findings from epidemiological studies have not been enough to proof these adverse effects. Given very limited research on human, the aim of this study was to investigate associations between cord blood BPA levels and reproductive and thyroid hormone levels of neonates and whether associations differed by neonate sex. Methods: Among 514 participants of the Hokkaido study who were recruited from 2002 to 2005 at one hospital in Sapporo, Japan. BPA level in cord blood was determined by ID-LC/MS/MS and the limit of quantification was 0.040 ng/ml. 9 types of reproductive hormone levels in cord blood were measured and thyroid hormone levels were obtained from neonate mass screening test data. 283 subjects those who had both BPA and hormone levels measurements were included for the final analyses. Results: Geometric mean of cord blood BPA was 0.051 ng/ml. After adjustment, BPA level was negatively associated with prolactin (PRL) (β=-0.38). There was an interaction between infant sex and BPA levels on PRL, weak negative association was found in boys (β=-0.12) whereas weak positive association was found in girls (β=0.14). BPA level showed weak positive association with testosterone, estradiol and progesterone levels in boys. No association was found between BPA and thyroid hormone levels. Conclusions: Our findings suggested that fetal BPA levels might be associated with certain reproductive hormone levels of neonate with sex-specific manner, though further investigations are necessary