Scientists discovered that exposure to the most commonly used pesticides is related to a higher risk of autism spectrum disorder. This is the outcome of one of the largest studies looking at the potential effects of pesticide exposure on still-developing fetuses and newborns.

The research was conducted under the supervision of Ondine von Ehrenstein, associate professor in the Fielding School of Public Health at the University of California in Los Angeles. The researchers analyzed autism registry data in California along with data on pesticide spraying in the state. The study included 38,000 people and 2,961 cases of autism.

Increased risk of autism up to 50%

The scientists discovered that women who were pregnant and lived within a 2,000 meter radius of a highly sprayed area were between 10% and 16% more likely to have children diagnosed with autism than women who lived further away from the sprayed areas. When they looked at diagnoses of autism spectrum disorder that also came with an intellectual disability, they found on average 30% higher percentages in children exposed to pesticides in the womb. Exposure in the first year of life increased the risk of autism to 50% compared to those who were not exposed to certain pesticides.

Prenatal and postnatal periods are the most vulnerable

Von Ehrenstein says the results point to two possible periods in which developing babies can be vulnerable to the neurotoxic effects of pesticides: in the womb and after birth. Babies who were exposed in their first year of life seemed to be at greater risk of developing autism with associated intellectual disabilities. The study also took into account potential confounders such as air pollution, socio-economic status, and whether mothers lived in urban or rural environments. But even in spite of these factors, a clear link remained.

Von Ehrenstein:

“Both prenatal and postnatal periods are vulnerable periods. And it doesn’t stop at birth.”

Unknowingly exposed to pesticides

The problem is that unlike behaviors such as smoking or alcohol consumption, exposure to pesticides is usually not under the control of people. And pregnant women are often unaware that they are being exposed to the chemicals. People can be exposed to pesticides, not just by spraying, but also by eating products that have been treated with the chemicals, so avoiding these fruits and vegetables can be another way to reduce the risk.

Von Ehrenstein hopes that the results will improve public awareness and encourage policy makers to change pest control policies and look for alternatives with less impact on public health.

Source: BMJ