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.
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.
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.
Geometric mean creatinine-adjusted BPA concentration of the averaged samples was 2.6 μg/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 μg BPA/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 <0.1). At 7 years, these associations were not statistically significant nor were any other behavioral problems.
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.