The number of children diagnosed with autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) has risen sharply in recent decades, and a new study points to the common plastic additive bisphenol A (BPA) as a possible reason.
BPA is used in many plastics and plastic manufacturing processes, and can be found in food and drink cans. But previous research has also linked it to health problems linked to hormone disruption, including breast cancer and infertility.
In this new study, researchers from Rowan University and Rutgers University in the US looked at three groups of children: 66 with autism, 46 with ADHD and 37 neurotypical children. In particular, they analysed the process of glucuronidation, a chemical process the body uses to remove toxins from the blood through the urine.
The research found that children with ASD and ADHD couldn’t eliminate BPA and another similar compound called diethylhexyl phthalate (DEHP) as efficiently as other children, potentially leading to longer exposure to their toxic effects.
“Detoxification of these two plasticisers is impaired in children with ASD and ADHD,” the researchers wrote in their published paper. “Consequently, their tissues are more exposed to these two plasticisers.”
However, only in the case of BPA was the difference statistically significant: efficiency was reduced by about 11 per cent in children with ASD and 17 per cent in children with ADHD, compared to the control group of children.
The researchers think that gene mutations in some people mean that BPA can’t be cleared as well as it needs to be, so it stays in the body. This could potentially cause damage to the development and functioning of nerve cells.
Conditions such as ASD and ADHD are thought to be caused by a combination of genetic and environmental influences, and this new study brings both together. But it’s only part of the story – not every child with a neurodevelopmental disorder had problems flushing out BPA, so there are other factors at play.
Work is continuing to find out exactly how ASD and ADHD take hold in the body – whether it’s in utero before birth, for example, or later in life – because there’s not enough data to show whether BPA exposure causes either condition.
“There is a large body of epidemiological evidence linking neurodevelopmental disorders to environmental pollutants such as plasticisers,” the researchers write.
“How important plasticiser-induced neurodevelopmental disorders are in the overall incidence of these disorders is not known, but they must be a significant proportion or they would not have been so easily detected in a metabolic study of moderate size such as this study.”
