27
Mar
Autism Linked to Wide Range of Commonly Used Pesticides
(Beyond Pesticides, March 27, 2019) Exposure to commonly used pesticides in the womb and during the first year of life is linked to a higher risk of developing autism, according to the study, “Prenatal and infant exposure to ambient pesticides and autism spectrum disorder in children: population based case-control study,” published in the journal BMJ last week. Although the study does not reveal a causal link, it adds to previous literature highlighting autism risks from pesticide exposure, and reinforces calls to limit pesticide exposure during early life critical windows of vulnerability. The authors note their findings “support the need to avoid prenatal and infant exposure to pesticides to protect the developing child’s brain.”
Researchers used data from California’s records of autism disorder diagnosis and birth rates from 1998 to 2010. Roughly thirty-five thousand healthy patients acted as a control, while scientists identified nearly three thousand patients with an autism diagnosis, of which 445 also displayed a co-occurring intellectual disability.
Data was then drawn from California’s pesticide use recording database, and eleven pesticides (glyphosate, chlorpyrifos, diazinon, acephate, malathion, permethrin, bifenthrin, methyl bromide, imidacloprid, avermectin, and myclobutanil) were analyzed for their use within 2000 meters (1.25 miles) of the homes of those involved in the study. Confounders (variables that can influence the statistical determination) such as the mothers age, socioeconomic status, and exposure to air pollution were adjusted for in the researchers’ model.
Results showed, when compared to a control group unexposed to the same pesticides during birth and infancy, modest increases in autism risk for exposure to glyphosate, chlorpyrifos, diazinon, malathion, avermectin and permethrin. For cases of autism with co-occuring intellectual disabilities, a more robust link was found for glyphosate, chlorpyrifos, diazinon, permethrin, methyl bromide, and myclobutanil. A similar link was found between exposures within the first year of life, with glyphosate revealing the strongest association – increasing risk of autism by 50% for exposures occurring during infancy.
This is not the first study to link prenatal and early life pesticide exposure to autism and learning disabilities. In fact, previous studies have found stronger links than the present research. A 2014 study found that pregnant women living less than a mile from crops sprayed with organophosphate insecticides increased risk of their child receiving an autism diagnosis by 60%. For women in the second trimester, chlorpyrifos exposure increased autism risks by 3.3 times. Exposure to synthetic pyrethroids, like permethrin and bifentrhin, during the last trimester of pregnancy corresponded with an 87% increased risk of an autism diagnosis. A 2017 study found that those living in zip codes where pesticides are aerially sprayed for mosquitoes with synthetic pyrethroids were 37% more likely to have higher rates of children diagnosed with autism and other developmental delays.
In an editorial co-released with the study, psychiatrists from the University of Utah note that the study focuses on outdoor air in an agricultural region and that the results may not be generalized to other settings. They also indicate that in many communities, “reducing maternal exposure to zero for a pesticide such as glyphosate might be close to impossible.” Beyond Pesticides rejects these assertions.
If there is a problem with outdoor areas, similar issues are likely to arise when pregnant mothers and young children are exposed to pesticides in their homes. For example, the same synthetic pyrethoids applied over farm fields are also found in RAID and other bug sprays, and evidence suggests that once applied they can persist in one’s home for over a year. Previous studies have linked the presence of these chemicals in a child’s body to increased rates of behavioral and emotional problems, externalizing and internalizing disorders, and accelerated puberty in boys.
Reducing maternal exposure to glyphosate can be solved simply by eliminating its use and cancelling its registration by the U.S. Environmental Protection Agency. More and more studies are finding that not only can organic feed the world, is should be considered an essential part of building a sustainable future.
As lead author of the current study, Ondine von Ehrenstein, PhD, said to TIME, “I would hope that these findings would make some policy makers think about effective public health policy measures to protect populations who may be vulnerable and living in areas that could put them at higher risk. Raising awareness in the public may be the way to eventually change practices and agricultural policies.”
For more information on the link between pesticides and autism and other learning disabilities, see Beyond Pesticides Pesticide Induced Diseases Database.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: BMJ (peer reviewed journal), TIME
