Study Links Parental Chemical Exposure at Work to Autism Severity in Children

A recent study published in the International Journal of Hygiene and Environmental Health has revealed a potential connection between parental exposure to chemicals in the workplace and increased behavioral challenges and developmental delays in children diagnosed with autism.

Autism, a neurodevelopmental disorder, presents a spectrum of challenges, including difficulties in social interaction, communication, and repetitive behaviors. Symptoms can vary significantly in severity among individuals.

Previous research has investigated how environmental factors may influence the likelihood of a child developing autism. However, this latest study is among the first to directly correlate parental occupational exposures with the severity of autism in children, as measured by the Autism Diagnostic Observation Schedule, 2nd edition (ADOS-2), a recognized tool for diagnosing autism.

The study was led by a team from the University of California, Davis (UC Davis), including Irva Hertz-Picciotto, who has been involved in extensive autism research for years through the CHARGE study, which examines the interplay between genetic and environmental factors in autism.

In collaboration with researchers from the National Institute for Occupational Safety and Health (NIOSH), the UC Davis team analyzed data from over 500 families participating in the CHARGE study, specifically focusing on children who had already received an autism diagnosis.

Industrial hygienists evaluated the job histories of both mothers and fathers, assessing their exposure to 16 different chemicals or agents from three months prior to pregnancy until childbirth. The chemicals studied included various plastics, automotive fluids, disinfectants, and pharmaceuticals.

Subsequently, researchers compared this exposure data with the autism severity scores obtained from the ADOS-2 and evaluated the children's behavioral patterns, cognitive abilities, and daily living skills.

The findings indicated significant associations between certain chemicals and autism characteristics among the children studied:

• Plastics and Polymers: Exposure to materials such as polyethylene, polypropylene, and polyvinyl chloride (PVC) was linked to reduced cognitive performance, diminished adaptive skills, and heightened behavioral issues, including hyperactivity and social withdrawal.
• Ethylene Oxide: This chemical, commonly used for sterilization, was associated with higher autism severity scores and poorer daily living skills.
• Phenol: Exposure to this compound correlated with increased severity of autism and behavioral symptoms such as hyperactivity and repetitive movements or vocalizations.

The lead researcher emphasized that these findings suggest parental exposure to specific workplace chemicals during crucial developmental periods may not only increase the likelihood of autism but also affect the severity and functioning outcomes for affected children.

However, the researchers acknowledged limitations in their study. The sample size may not have been large enough to detect links for less prevalent exposures, and the estimates of exposure relied on reported job histories, which may not accurately reflect actual chemical exposure levels. Furthermore, while certain chemicals showed correlations with autism traits, causation was not established.

Looking ahead, the authors advocate for further research to better understand how these exposures affect brain development and emphasize the need to include paternal exposure in studies related to reproductive health and child neurodevelopment, as many significant associations were linked to fathers' job exposures.

Notably, the strongest cognitive deficits in children with autism were linked to fathers' exposure to plastics and polymers, which corresponded with significantly lower skills in areas such as fine motor coordination, visual processing, and language comprehension and expression.

This research underscores the importance of workplace safety not only for current employees but also for safeguarding the health of future generations. It highlights the need for greater awareness of how occupational hazards may impact child development.