Urinary sexual steroids associated with bisphenol A (BPA) exposure in the early infant stage: Preliminary results from a Daishan birth cohort

Background: Many surveys have shown that older children are ubiquitously exposed to bisphenol A (BPA), and many laboratory studies have shown that BPA exposure has adverse effects related to estrogenic disruption, whereas the evidence in infants has not yet been observed. Methods: Women in early pregnancy were recruited by the Maternal and Child Health and Family Planning Service Center, Daishan, China, from March 2012 to December 2014. After delivery, urine samples were collected from the diapers of 59 infants (0 to 6 months of age). Urinary BPA, estradiol (E-2), testosterone (T), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and creatinine were analyzed. The partial correlation and multivariable linear regression were applied to assess the associations of BPA with E-2, T, FSH, and LH for each of the development stages: at birth, 14 days, 28 days, 42 days, 3 months, and 6 months. Results: For both genders from birth to 6 months, infants showed randomly changed urinary BPA but regularly changed hormones, i.e., the monotonic decreasing E-2 and T, the U shaping E-2/T and upside down U shaping FSH and LH with extreme values at approximately the 14-day stage, respectively. However, the creatinine-adjusted FSH for all stages and E-2 from 6 months were genders different. After adjustment for creatinine, gender, and infant body mass index, BPA was positively associated with E2 both in male (for 14-, 28-, and 42-day stages) and female (for 14-, 28-, 42-day, and 3-month stages) infants; positively associated with E-2/T ratio in both male for 14- and 28-day stages) and female (for 14-day stage) infants; and positively associated with T in female (for 3-month stage) infants. Conclusions: To the best of our knowledge, this is the first time that associations of BPA with E-2, E-2/T, and T in infant urine were observed. The results suggested that the infants first demonstrate a surge of steroids after leaving the maternal uterus's steroidogenic environment (i.e., mini-puberty) and may be affected by BPA; this pollution may disrupt the premature gonad function at some important developmental windows. (C) 2017 Elsevier B.V. All rights reserved.