Written by Joyce Smith, BS. This study found that higher urinary BPA concentrations were associated with ADHD in U.S. children and were stronger in boys than in girls.

Environmental health - waterAttention-deficit/hyperactivity disorder (ADHD), previously known as attention deficit disorder or ADD, is a neurobehavioral disorder characterized by core symptoms of inattentiveness, distractibility, hyperactivity, and impulsivity 1. Bisphenol A (BPA) is an industrial chemical that has been used to make polycarbonate plastics and epoxy resins since the 1960’s and can be found in a great range of products including containers that store food and beverages, such as metal food can linings and water bottles, dental sealants, sports safety equipment and adhesives 2. BPA, prevalent in the urine of 93% of the U.S. population 3, enters the body when foods and beverages containing BPA are ingested 4. BPA’s endocrine disrupting properties and agonist effects on estrogen receptors have given credence to its potential sex-specific effects on neurobehavior 5, and prompted a strong interest in a potential effect on the development of ADHD in children.

A multicenter Canadian and U.S. research team 6 used data of 460 children, eight to fifteen years of age, from the 2003-2004 U.S. National Health and Nutrition Examination Survey (NHANES) to examine a potential link between BPA exposure and the development of Attention-Deficit/Hyperactivity Disorder. Using multivariable logistic regression, the team’s primary outcome was a potential correlation between urinary concentrations of BPA (limit of detection 0.36 ug/L) and a current diagnosis of ADHD. The secondary outcome was a past history of ADHD.

  • Bivariate analyses revealed that higher urinary BPA concentrations were associated with ADHD: 11.2% of children with BPA levels at or above the median of the sample (3.9ug/L) had ADHD, whereas 2.9% of children with BPA levels below the median had ADHD (11.2% vs 2.9%; p=0.01). These associations were stronger in boys than in girls.
  • A similar pattern was seen for the secondary outcome. Multivariable analyses, when adjusted for potential cofounders, found that children with urinary concentrations at or above the median were more than 5 times more likely to have an ADHD diagnosis than children with levels below the median.
  • Sex-stratified analyses of the data showed that boys with urinary BPA concentration at or above the mean were almost 11 times more vulnerable to ADHD than were boys or girls with concentrations below the median.

Researchers conclude that while previous studies conducted in younger children have shown no differences in sex-specific vulnerability to BPA exposure, this study showed that the increased incidence in older, school-age children was stronger in boys. This study highlights the growing scientific evidence on neurobehavioral effects of BPA in children and suggests that future studies be done to determine whether reducing BPA exposure may be an important factor in ADHD prevention.

Study limitations include the use of a single spot urine test to measure BPA exposure. BPA has a short half-life, thus serial tests should be done for greater accuracy (97% of study samples detected BPA). A cross-sectional study design, a lack of early childhood and prenatal BPA measurements that prohibited the study of neurobehavioral effects of prenatal exposure, genetic influences, and care-giver interviews were also study limitations.

Source: Tewar, Shruti, Peggy Auinger, Joseph M. Braun, Bruce Lanphear, Kimberly Yolton, Jeffery N. Epstein, Shelley Ehrlich, and Tanya E. Froehlich. “Association of bisphenol A exposure and attention-deficit/hyperactivity disorder in a national sample of US children.” Environmental research 150 (2016): 112-118.

© 2016 Elsevier Inc. All rights reserved.

Posted September 9, 2019.

Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from  the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.

References:

  1. Froehlich TE, Lanphear BP, Epstein JN, Barbaresi WJ, Katusic SK, Kahn RS. Prevalence, recognition, and treatment of attention-deficit/hyperactivity disorder in a national sample of US children. Archives of pediatrics & adolescent medicine. 2007;161(9):857-864.
  2. Vandenberg LN, Hauser R, Marcus M, Olea N, Welshons WV. Human exposure to bisphenol A (BPA). Reproductive Toxicology. 2007;24(2):139-177.
  3. Kang J-H, Kondo F, Katayama Y. Human exposure to bisphenol A. Toxicology. 2006;226(2-3):79-89.
  4. Calafat AM, Ye X, Wong L-Y, Reidy JA, Needham LL. Exposure of the US population to bisphenol A and 4-tertiary-octylphenol: 2003–2004. Environmental health perspectives. 2007;116(1):39-44.
  5. Gioiosa L, Fissore E, Ghirardelli G, Parmigiani S, Palanza P. Developmental exposure to low-dose estrogenic endocrine disruptors alters sex differences in exploration and emotional responses in mice. Hormones and behavior. 2007;52(3):307-316.
  6. Tewar S, Auinger P, Braun JM, et al. Association of bisphenol A exposure and attention-deficit/hyperactivity disorder in a national sample of US children. Environmental research. 2016;150:112-118.