Exposure to bisphenol A, which is widely used in consumer products, may lead to behavioral problems in children, according to a study by Joe M. Braun, Ph.D., of the Harvard School of Public Health, Boston, and his associates.
Bisphenol A (BPA) can be found widely in items such as dental sealants, medical equipment, thermal receipts, and food and beverage containers and linings. Because of its ubiquity, exposure is nearly inescapable.
Data was collected from 244 mother-child pairs participating in the HOME (Health Outcomes and Measures of the Environment) study, a prospective birth cohort in the Cincinnati metropolitan area. Maternal spot urine samples were collected at approximately 16 and 26 weeks’ gestation and within 24 hours after birth during 2004-2006. Children’s spot urine samples were collected once per year for the first 3 years of their lives (Pediatrics 2011 Oct. 24 [doi:10.1542/peds.2011-1335]).
The concentrations of total (free plus conjugated) species of BPA were measured at the Centers for Disease Control and Prevention. Researchers used the mean of at least two samples each for the gestational and childhood periods.
At 3 years of age, children were evaluated by their parents using the BASC-2 (Behavior Assessment System for Children–2) Parent Rating Scale for preschoolers. The BASC-2 is a valid, reliable, 134-item, parent-report assessment of a child’s problem behaviors. The parents also evaluated the children’s executive functions using the BRIEF-P (Behavior Rating Inventory of Executive Function–Preschool).
The mothers’ BPA levels were relatively stable from the first sample until birth. Children’s levels, on the other hand, decreased steadily from the first year to the third.
Gestational BPA concentrations were associated with an increase in BASC-2 hyperactivity scores by 0.5, anxiety by 7.0, and depression by 4.9. The increases were sharper in girls, suggesting that they are more susceptible to gestational BPA. Girls saw increases of 9.1 in hyperactivity, 12 in anxiety, and 11 in depression, whereas boys actually saw 6.3 and 0.5 decreases in hyperactivity and depression, respectively, coupled with a smaller increase of 1.3 in anxiety, Dr. Braun and his associates said.
In an accompanying e-letter, biologist James M. Howard suggested that a possible explanation of the more pronounced effect of BPA in girls occurs because BPA increases maternal testosterone (Endocr. J. 2004;51:165-9), and this increase should affect female fetuses more than male fetuses.
In contrast, gestational BPA concentrations were positively associated with emotional control and inhibition scores on the BRIEF-P assessment, and there was no association between BPA and executive function at 3 years of age.
The effects of gestational BPA are still unclear, but patients can attempt to avoid it as a precaution. Health professionals should remind patients that it is not easy to completely steer clear of BPA, and more research is needed to fully understand its effects, Dr. Braun and his associates said.
The study was funded by the National Institutes of Health and the U.S. Environmental Protection Agency. Dr. Braun and his associates said they have no relevant financial disclosures.