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 Mothers who were exposed to household or agricultural pesticides
just before and during their pregnancies but who took high-dose
folic acid cut in half the risk of their children developing autism
when compared to women who received low doses of the vitamin, lead
author Rebecca Schmidt said in a phone interview.
“If there’s a chance you might get pregnant, . . . take your folic
acid and try to avoid unnecessary pesticides,” said Schmidt, an
epidemiologist and professor at the Medical Investigations of
Neurodevelopment Disorders (MIND) Institute at the University of
California, Davis.
The research confirmed previous studies connecting maternal
pesticide exposure to autism spectrum disorder (ASD), a
developmental disability marked by social, communication and
behavioral challenges.
But the report in Environmental Health Perspectives breaks new
ground by finding that children prenatally exposed to pesticides
were less likely to be diagnosed with autism if their mothers took a
high dose of folic acid.
The findings led investigators to conclude that folic acid might
reduce, though not eliminate, an increased risk of autism associated
with maternal pesticide exposure.
Folic acid, or vitamin B-9, is contained in green leafy vegetables
and fortified cereal.
The U.S. Preventive Services Task Force and other health groups
already urge women with any chance of becoming pregnant to take
daily folic acid supplements because B-9 deficiency has long been
tied to brain and spinal cord birth defects.
The new findings, in addition to underscoring the importance of
folic acid, highlight the role environmental pollutants appear to
play in the development of autism, said Joseph Braun, an
epidemiologist at the Brown School of Public Health in Providence,
Rhode Island, who was not involved with the study.
“This is another piece of the puzzle for environmental risk factors
for autism,” he said in a phone interview. “There has really not
been as much attention paid to environmental risk factors for autism
as there has been for genetic risk factors.”
An estimated one of every 68 children in the U.S. was diagnosed with
an autism spectrum disorder in 2012, according to the U.S. Centers
for Disease Control and Prevention. Since the 1990s, rates of autism
have spiked across the nation. Boys are 4.5 times more likely to be
diagnosed with ASD than girls.
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Study participants included 296 children diagnosed with autism and
220 who developed typically. All were between 2 and 5 years old and
born in California from 2000 until 2007.
Researchers interviewed the children’s mothers about their folic
acid intake as well as their exposure during pregnancy to household
pesticides, including pet flea and tick products, professional pest
control or extermination, and indoor and outdoor sprays and
chemicals intended to kill insects. Investigators also linked data
from state pesticide-use reports with mothers’ addresses to
determine exposure to agricultural sprays.
Women with below-average folic acid intake and exposure to any
indoor pesticides had 2.5 times the risk of having a child with
autism compared to unexposed mothers who took at least 800
micrograms of folic acid, the amount in prenatal vitamins.
Mothers who were exposed regularly to pesticides for three months
before and after conception were at the highest risk of having
children who developed ASD, Schmidt said.
While folic acid reduced the risk of a child developing autism, it
did not eliminate it, the study found.
The study relied on mothers’ memories about their household
pesticide exposure, a limitation of the research, Schmidt said. But
researchers were able to draw similar conclusions from California
pesticide-use data as they did from self-reported pesticide usage,
strengthening the findings, Braun noted.
The study shows promise for nutritional supplements mitigating the
damage from prenatal pollutants, he and Schmidt said.
“Maybe this is a way to attenuate effects of environmental
pollutants and contaminants that we don’t really have a lot of
control over,” Schmidt said.
SOURCE: http://bit.ly/2y3vUSr Environmental Health Perspectives,
online September 12, 2017.
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