New research found a autism rates are higher in regions where genital malformations in newborn males are more common, possibly indicating environmental
A research team found that autism rates rose by 283 percent for every one percent of genital malformation frequency, a University of Chicago Medical Center news release reported. Intellectual rates were also found to increase by 94 percent. Other risk factors such as gender and ethnicity were factored into the study.
"Autism appears to be strongly correlated with rate of congenital malformations of the genitals in males across the country," study author Andrey Rzhetsky, PhD, professor of genetic medicine and human genetics at the University of Chicago news release reported. "This gives an indicator of environmental load and the effect is surprisingly strong."
The researchers made their findings by looking at an insurance claim dataset that covered about one-third of the U.S. population. The team compared their statistical baseline frequency of autism and intellectual disability (ID) with actual rates of these disorders by country. Deviations from the baseline indicated local causes of disability.
Male fetuses are particularly susceptible to contaminants such as "lead, sex hormone analogs, medications and other synthetic molecules," the news release reported. Exposure to these factors is believed to contribute to genital malformations such as micropenises and undescended testicles.
Non-reproductive congenital malformations and viral infections were also linked to a higher rate of autism and ID. The researchers believe the conditions are not linked (or only very weakly) to vaccines since local environments are believed to influence the cases.
"We interpret the results of this study as a strong environmental signal," Rzhetsky said. "For future genetic studies we may have to take into account where data were collected, because it's possible that you can get two identical kids in two different counties and one would have autism and the other would not."
