A quarterly publication of the Autism Research Institute

The Autism Research Review International is quarterly publication of the Autism Research Institute

Spring, 2024 | Number 2, Volume 38

Environmental toxins implicated in rising rates of ASD, ADHD

Environmental toxins may play a key role in the rising rates of autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), according to a new study from researchers in the United
States.

Surveying nearly 8,000 adults using a questionnaire designed to identify individuals with chemical intolerances, Raymond Palmer and colleagues found that parents with chemical intolerance scores in the top tenth percentile were 5.7 times more likely to report having a child with ASD compared to parents in the bottom tenth percentile. They also were 2.1 times more likely to report having a child with ADHD.

Senior study author Claudia Miller says, “This is the first-ever article in the medical literature showing that chemical intolerance in parents can predict the risk of autism and ADHD in their children, and suggests that reducing exposures prior to and during pregnancy could help prevention.”

In earlier research, Miller and colleagues detected a strong association between chemical intolerance and immune system cells called mast cells. When exposed to foreign substances such as chemicals, these cells can release inflammatory molecules. Once mast cells are sensitized, the researchers say, even low levels of exposure to the original toxin or other chemicals can lead to inflammation. Their work suggests that increasing rates of autism and ADHD may be linked to toxic chemicals “turning on” or “turning
off” critical mast cell genes, with these epigenetic changes being transmitted from one generation to the next.

The researchers caution that their current study cannot determine the cause of the association between chemical sensitivity and ASD or ADHD, and they stress that more research on this topic is needed. They conclude, “The potential role of environmental toxicants in influencing epigenetics and mast cell function is a complex and emerging area of research…. Acknowledging the need for further evidence, we hope this study contributes to an improved understanding of the potential role of environmental factors in the global rise of autism and ADHD.”


Citations

“Assessing chemical intolerance in parents predicts the risk of autism and ADHD in their children,” Raymond F. Palmer, David Kattari, Rodolfo Rincon, and Claudia S. Miller, Journal of Xenobiotics, March 2024 (free online). Address: Raymond Palmer, Department of Family and Community Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, [email protected].

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“Parental avoidance of toxic exposures could help prevent autism, ADHD in children, new study shows,” news release, University of Texas Health Science Center at San Antonio, March 28, 2024.