Tuesday, September 26, 2017

An article published on September 8, 2017 in Environmental Health Perspectives reveals a protective role for food fortification and supplementation with folic acid by pregnant women against the increased risk of giving birth to a child diagnosed with autism spectrum disorders that is associated with prenatal exposure to pesticides. Supplementation with folic acid or folate has been recommended to women during their reproductive years to help lower the risk of birth defects, including spina bifida and anencephaly, in their infants.

The current case-control study involved 220 children with typical development and 296 children diagnosed with autism spectrum disorder enrolled in the Childhood Autism Risks from Genetics and the Environment (CHARGE) study. Information concerning maternal folic acid intake and household pesticide exposure three months prior to conception and during pregnancy was obtained through telephone interviews. Household pesticides included flea or tick soaps or shampoos; sprays, dusts, powders, or skin applications for fleas or ticks on pets; professional pest control or extermination; ant, fly, or cockroach-control products; and indoor foggers.

In comparison with women who consumed a total of at least 800 micrograms (mcg) per day folic acid from supplements and fortified food sources during the first month of pregnancy and who had no known pesticide exposure three months prior to and during pregnancy, indoor pesticide-exposed mothers who consumed less than 800 mcg folic acid had a two and a half times greater risk of giving birth to a child diagnosed with autism spectrum disorder. Additionally, women with low folic acid intake and greater than six months of regular exposure to pet pesticides during their pregnancies had a nearly four times greater risk and those exposed to regular use of outdoor sprays and foggers for at least six months had a more than four times greater risk of having an autistic child. Agricultural pesticide exposure combined with low folic acid intake was also associated with increased autism risk.

"Folic acid intake below the median and exposure to pesticides was associated with higher risk of autism than either low intake or exposure alone," reported first author Rebecca J. Schmidt, who is an assistant professor in the Department of Public Health Sciences at the University of California, Davis. "The mothers who had the highest risk were the ones who were exposed to pesticides regularly."

"We found that if the mom was taking folic acid during the window around conception, the risk associated with pesticides seemed to be attenuated," she added. "Mothers should try to avoid pesticides. But if they live near agriculture, where pesticides can blow in, this might be a way to counter those effects."

"Folate plays a critical role in DNA methylation (a process by which genes are turned off or on), as well as in DNA repair and synthesis," Dr Schmidt observed. "These are all really important during periods of rapid growth when there are lots of cells dividing, as in a developing fetus. Adding folic acid might be helping out in a number of these genomic functions."