Plastic contaminant may raise risk of autism, ADHD: Study

New York: Autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD), that have recently seen a significant rise, may be linked to the common plastic additive, bisphenol A (BPA), according to a study.

BPA, used in everyday objects such as in medical devices, compact discs, dental sealants, water bottles, the lining of canned foods and drinks, among others, has previously been linked to several health issues, including cancer.

The study, published in the public access journal PLOS ONE, showed that children with ASD and ADHD often have a reduced ability to clear BPA from their bodies, thereby increasing their exposure to BPA.

Previous studies have found associations between children with autism and exposure to BPA.

In the new study, researchers from the Rowan University in New Jersey, US, found that the reason for the link is decreased efficiency in a key step involved in BPA detoxification.

After BPA is ingested or inhaled, it is filtered from the blood in the liver through a process called glucuronidation. Glucuronidation is the process of adding a sugar molecule to a toxin. Doing so makes the toxin water soluble, allowing it to quickly pass out of the body through urine.

Humans show genetic variability in their ability to detoxify BPA. Genetically susceptible individuals have more difficulty detoxifying their blood through this process, meaning their tissues are exposed to BPA at higher concentrations for longer time periods.

The team measured the efficiency of glucuronidation in three groups of children in the US: 66 with autism, 46 with ADHD and 37 healthy children.

The findings showed that for a significant proportion of children with autism, the ability to add the glucose molecule to BPA is about 10 per cent less than that of control children. For a significant proportion of children with ADHD, it's about 17 per cent less.

The compromised ability to clear such environmental pollutants from the body is "the first hard biochemical evidence of what the linkage is between BPA and the development of autism or ADHD," said lead author T. Peter Stein, Professor of surgery at Rowan-Virtua School of Osteopathic Medicine.

"We were surprised to find that ADHD shows the same defect in BPA detoxification," he added.

The inability to effectively clear these chemicals from the blood is not present in every child with the neurodevelopmental disorders, but compromised clearance of BPA is a "major pathway, otherwise it would not have been so readily detectable in a study of moderate size," Stein said.

However, more research is needed to determine whether autism and ADHD are developed in utero through increased exposure to the mother or to the child sometime following birth, Stein said, noting that there can be other factors too.