Associations of prenatal urinary bisphenol A concentrations with child behaviors and cognitive abilities (Lay summary)

Braun JM, Muckle G, Arbuckle TE, Bouchard MF, Fraser WD, Ouellet E, Séguin JR, Oulhote Y, Webster GM, Lanphear BP. Environmental Health Perspectives 2017 Jun 16;125(6):067008. doi: 10.1289/EHP984.

Bisphenol A (BPA) is a chemical used to make hard clear plastic (known as polycarbonate) (e.g., some water bottles).  BPA is also used to make epoxy resins like the ones used as part of the protective lining of metal food and beverage cans. BPA is also used in some paper and paper products (e.g., thermal receipts).   Canadians are exposed to BPA primarily through diet and dermal exposure.  A recent national survey reported that 93% of the population had detectable levels of BPA in their urine (https://www.canada.ca/en/health-canada/services/environmental-workplace-health/reports-publications/environmental-contaminants/fourth-report-human-biomonitoring-environmental-chemicals-canada.html).  Some studies have suggested that prenatal BPA exposure may increase the risk of behavioral disorders and affect cognitive abilities in children.  Cognitive abilities are a measure of an individual’s ability to reason, learn, understand and remember.

As part of the MIREC Study, data from 812 mother-child pairs were analysed to see if exposure to BPA during pregnancy was associated with measures of child behavior and cognition at age 3 years. Maternal urine was collected during the first trimester and analysed for BPA.   The parents answered questions about their child’s behavior and the children took some tests to measure their cognitive abilities (e.g., IQ).

Eighty-six percent of the women in this study had detectable levels of BPA in their urine.  Maternal urine BPA levels were not associated with their child’s scores on the cognition tests. Some results suggested that prenatal exposure to BPA may be associated with small decreases in scores for memory in boys, but better scores in girls.  BPA was also associated with anxiety, depression, and somatic behaviours (experiences of physical symptoms that cannot be explained by underlying medical or neurologic conditions) in boys, but not girls. BPA was also associated with worse scores on a test that measured interpersonal behaviors, communication, and repetitive or stereotypic behaviors in both boys and girls.

In conclusion, this study found that prenatal BPA exposure was associated with some aspects of children’s behaviors, especially in boys.  However, this study had several important limitations which must be considered.  For example, data were not available on other predictors of child behavior, such as the parents’ behavior and their cognitive abilities.  In addition, BPA exposure was only measured once during the first trimester of pregnancy, whereas exposure during other periods of fetal development, infancy, or childhood might affect behavior and cognition.  Therefore, these results should be interpreted cautiously.  Studies which deal with these limitations are needed to gain a better understanding of early-life BPA exposure and child behavior.