BACKGROUND: Bisphenol A (BPA) may be a neurodevelopmental toxicant, but evidence is not consistent in terms of the sex-specific patterns of the associations and the specific behavioral or cognitive domains most affected.
OBJECTIVE: To examine the effects of prenatal BPA exposure on cognitive, psychomotor, and behavioral development in 438 children at 1, 4 and 7 years of age.
METHODS: BPA was measured in spot urine samples collected in trimester 1 and 3 of pregnancy from women participating in the INMA-Sabadell birth cohort study. Cognitive and psychomotor development was assessed at 1 and 4 years using psychologist-based scales. Attention deficit hyperactivity disorder (ADHD) symptoms and other behavioral problems were assessed at 4 years by teachers and at 7 years by parents using questionnaire-based rating scales.
RESULTS: Geometric mean creatinine-adjusted BPA concentration of the averaged samples was 2.6 microgram/g creatinine. BPA exposure was not associated with the cognitive scores or their subscales at 1 and 4 years of age. At 1 year of age, exposure in the highest tertile of BPA concentrations was associated with a reduction of psychomotor scores (T3 vs T1 β=-4.28 points, 95% CI: -8.15, -0.41), but there was no association with psychomotor outcomes at 4 years. At 4 years, BPA exposure was associated with an increased risk of ADHD-hyperactivity symptoms (Incidence Rate Ratio (IRR) per log10 microgramBPA/g creatinine increase=1.72; 1.08, 2.73) and this association was stronger in boys than in girls. Further, boys had an increased risk of ADHD-inattention symptoms whereas girls showed a reduced risk (p for interaction less than 0.1). At 7 years, these associations were not statistically significant nor were any other behavioral problems.
CONCLUSIONS: These results suggest that prenatal BPA exposure does not affect cognitive development up to age 4 years. Associations are observed with psychomotor development and ADHD-related symptoms at early ages, but these do not appear to persist until later ages.
