Study Finds Strong Link Between Autism Disorders and Environmental Factors
A new study has reportedly found a strong link between autism spectrum disorders (ASD) and environmental pollution. The large-scale study discovered that in areas with higher autism rates, there are also more genital birth defects in boys, which suggest that environmental factors could be at play.
In this study, the research team headed by Andrey Rzhetsky, a professor of genetic medicine at the University of Chicago, examined medical data on almost 100 million health insurance claims within the U.S. The researchers focused on autism rates, intellectual disabilities and male genital malformations, such as a micropenis, undescended testicales and hypospadias, on a county-by-county basis. Hypospadias occurs when the urethral opening formed on the underside of the penis. For the purpose of this study, the researchers stated that genital malformations indicated maternal exposure to potentially deadly environmental pollutants.
The researchers calculated that the rate of genital birth defects ranged from zero to a little over two percent in the counties. For every one percent jump in birth defects, the researchers found that the autism rate increased by almost 300 percent. This relationship was still very strong after county demographics were accounted for. The researchers also found that for every one percent increase in genital malformations, there was a 94 percent increase in the rate of intellectual disabilities.
"Essentially what happens is during pregnancy there are certain sensitive periods where the fetus is very vulnerable to a range of small molecules - from things like plasticizers, prescription drugs, environmental pesticides and other things," Rzhetsky said to FOX News. "And some of these small molecules essentially alter normal development. It's not really well known why, but it's an experimental observation, especially in boys and especially in the reproductive system."
The researchers concluded that autism was most likely influenced by environmental factors. However, the team noted that this relationship was still not a cause-and-effect one. Furthermore, the researchers did not identify potential environmental toxins that could be linked to increased autism rates.
"This study was not designed to figure out what the [environmental] factors are," said Alycia Halladay, senior director of environmental and clinical sciences for the advocacy group Autism Speaks. Halladay, who was not involved with the study, stated that there is a lot of evidence suggesting that both genetics and environmental factors affect one's autism risk.
"There is a lot of research focused on the genetics," Rzhetsky said reported by Philly. "But environment plays a big role."
The study was published in PLOS Computational Biology