Confirming previous findings, a large study from the University of Chicago has found that autism is linked to toxic environmental exposure. The research examined data from nearly a third of the U.S. population, which showed that both autism spectrum disorders and intellectual disabilities increased as exposure increased in region-by-region testing. The research measured clusters of autism incidence together with exposure rates in different counties and states across the country.
The areas with greater environmental toxin exposures had significantly increased autism rates. The correlation was significant among both boys and girls, but stronger among girls. Proximity to urban areas also increased autism incidence. For every 1 percent increase in urbanization, there was about a 3 percent rise in autism and intellectual disabilities. Influential toxins include pesticides, plasticizers, lead and pharmaceuticals.