Scientists discovered that exposure to the most commonly used pesticides is associated with an increased risk of autism. This is evident from one of the largest studies ever conducted on the possible effects of pesticides on developing fetuses and newborn babies.
The study was conducted under the leadership of Ondine von Ehrenstein, associate professor at the Fielding School of Public Health at the University of California, Los Angeles. The researchers analyzed autism registry data from California together with data on pesticide spraying in the state. The study included 38,000 people and 2,961 cases of autism.
Increased risk of autism of up to 50%
The scientists discovered that women who were pregnant and lived within a radius of 2,000 meters of a heavily sprayed area were between 10% and 16% more likely to have children diagnosed with autism spectrum disorder than women who lived farther away from the sprayed areas. When they examined diagnoses of autism spectrum disorder that were also accompanied by an intellectual disability, they found average rates that were 30% higher among children who had been exposed to pesticides in the womb. Exposure during the first year of life increased the risk of autism by up to 50% compared with those who were not exposed to certain pesticides.
Prenatal and postnatal periods most vulnerable
Von Ehrenstein says that the results point to two possible periods during which developing babies may be vulnerable to the neurotoxic effects of pesticides: in the womb and after birth. Babies who were exposed during their first year of life appeared to have a greater risk of developing autism with associated intellectual disabilities.
Von Ehrenstein:
"Both prenatal and postnatal periods are vulnerable periods. And it does not stop at birth."
The study also took possible confounders into account, such as air pollution, socioeconomic status, and whether the mothers lived in urban or rural environments. But even after accounting for these factors, a clear link remained.
Unknowingly exposed to pesticides
The problem is that, unlike behaviors such as smoking or alcohol consumption, exposure to pesticides is usually beyond people's control. And pregnant women are often unaware that they are being exposed to the chemicals. People can be exposed to pesticides not only through spraying, but also by eating products treated with the chemicals, so avoiding these fruits and vegetables may be another way to reduce the risk.
Von Ehrenstein hopes that the results will improve public awareness and encourage policymakers to change pest-control policies and seek alternatives with less impact on public health.
Source: BMJ