Bisphenol-A, widely used in plastics, receipt paper and canned food linings, is a culprit in some children developing hyperactivity : a July 2017 review, available online 7 March 2018, of more than 30 scientific studies, concludes early life exposure to the endocrine disrupting chemical BPA leaves children more susceptible to hyperactivity later in life.
- We used the OHAT systematic review framework to examine if early exposure to BPA has an effect on hyperactivity
- We found that, in both rodents and humans, early exposure to BPA is linked to increased hyperactivity
- Integration of animal and human evidence finds that BPA is a presumed hazard to human health
- We suggest the development of clinical recommendations for avoiding BPA exposure, especially for pregnant women and children
2018 Study Abstract
Attention-deficit hyperactivity disorder (ADHD) has increased in prevalence in the past decade. Studies attempting to identify a specific genetic component have not been able to account for much of the heritability of ADHD, indicating there may be gene-environment interactions underlying the disorder, including early exposure to environmental chemicals. Based on several relevant studies, we chose to examine bisphenol A (BPA) as a possible contributor to ADHD in humans. BPA is a widespread environmental chemical that has been shown to disrupt neurodevelopment in rodents and humans.
Using the Office of Health Assessment and Translation (OHAT) framework, a systematic review and meta-analysis was designed to determine the relationship between early life exposure to BPA and hyperactivity, a key diagnostic criterion of ADHD.
Searches of PubMed, Web of Science, and Toxline were completed for all literature to January 1, 2017.
Study eligibility criteria
For inclusion, the studies had to publish original data, be in the English language, include a measure of BPA exposure, and assess if BPA exposure affected hyperactive behaviors in mice, rats or humans. Exposure to BPA had to occur at <3 months of age for humans, up to postnatal day 35 for rats and up to postnatal day 40 for mice. Exposure could occur either gestationally (via maternal exposure) or directly to the offspring.
Study appraisal and synthesis methods
Studies were evaluated using the OHAT risk of bias tool. The effects in humans were assessed qualitatively. For rodents exposed to 20 μg/kg/day BPA, we evaluated the study findings in a random effects meta-analytical model.
A review of the literature identified 29 rodent and 3 human studies. A random effects meta-analysis showed significantly increased hyperactivity in male rodents. In humans, early BPA exposure was associated with hyperactivity in boys and girls.
Limitations, conclusions, and implications of key findings
We concluded that early life BPA exposure is a presumed human hazard for the development of hyperactivity. Possible limitations of this systematic review include deficiencies in author reporting, exclusion of some literature based on language, and insufficient similarity between human studies. SRs that result in hazard-based conclusions are the first step in assessing and mitigating risks. Given the widespread exposure of BPA and increasing diagnoses of ADHD, we recommend immediate actions to complete such risk analyses and take next steps for the protection of human health. In the meantime, precautionary measures should be taken to reduce exposure in pregnant women, infants and children. The present analysis also discusses potential mechanisms by which BPA affects hyperactivity, and the most effective avenues for future research.
Sources and Press Releases
- Prenatal exposure to bisphenol A and hyperactivity in children: a systematic review and meta-analysis, sciencedirect, article/pii/S0160412017311960, 7 March 2018.
- Scientists call BPA exposure ‘presumed health hazard’ for hyperactivity, Environmental Health News, Mar 08, 2018.
- BPA linked to hyperactivity, foodpackagingforum, March 9, 2018.
- Featured image Vance Osterhout.