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Environmental Factor

Environmental Factor

Your Online Source for NIEHS News

April 2019

Autism Awareness Day to headline NIEHS social media event April 2nd

Internet users are invited to a Q and A session with autism experts on Reddit's 'Ask Me Anything' thread.

Cindy Lawler, Ph.D., head of NIEHS Genes, Environment, and Health Branch Lawler manages NIEHS grants on ASD research. (Photo courtesy of Steve McCaw)

In recognition of World Autism Awareness Day on April 2, NIEHS will host its first Reddit Ask Me Anything (AMA). A Reddit AMA is a way for experts to share their expertise through an online question and answer session (see sidebar). Through the NIEHS AMA, anyone with an internet connection can learn more about the work that NIEHS is doing to better understand how our environment affects our health.

NIEHS lined up two scientists to tackle questions from the Reddit community on the environmental risk factors of autism spectrum disorder (ASD). Cindy Lawler, Ph.D., head of the NIEHS Genes, Environment, and Health Branch, will be joined by Rebecca Schmidt, Ph.D., from the University of California at Davis.

Genes, environment both matter

ASD is a group of complex disorders that involve brain development. Autism symptoms, which appear early in childhood, include difficulties in social communication, along with restricted patterns of behavior and interests. Although it was once considered rare, current estimates indicate that autism affects about 1 in 59 children in the United States.

Scientists now know that ASD is influenced by a combination of genetic and environmental factors. NIEHS funds researchers who study how environmental exposures early in life may combine with genetic susceptibility to alter brain development and create the core symptoms of autism.

Folic acid near conception

Rebecca Schmidt, Ph.D., from the University of California at Davis Schmidt is an environmental scientist who studies how nutrition and the environment affect the development of children. (Photo courtesy of Patrick Hugunin, the MIND Institute)

Schmidt studies intake of folic acid, which is the synthetic form of folate, by pregnant women. She found that if a woman takes folic acid near the time of conception, it has the potential to reduce occurrence of ASD by 40 percent. Folic acid is one of the first factors shown to reduce the occurrence of ASD.

Folic acid appears to be especially helpful against ASD in mothers and children who are genetically susceptible. Furthermore, Schmidt’s studies provide evidence that folic acid supplements near the time of conception might also counter the risk associated with exposures during pregnancy to environmental contaminants, like pesticides, air pollution, and phthalates.

Her recent work provides hope for younger siblings of children with autism. These children are at higher risk due to shared genetics and environment. Schmidt reported that when mothers of these children took prenatal vitamins with folic acid in the first month of pregnancy, the recurrence of autism was reduced by about half.


Schmidt is also looking at how folic acid works to protect against autism. There are many ways the many nutrients in prenatal vitamins could be critical for brain development and could protect mechanistic pathways connected to autism.

Citation: Schmidt RJ, Iosif AM, Guerrero Angel E, Ozonoff S. 2019. Association of maternal prenatal vitamin use with risk for autism spectrum disorder recurrence in young siblings. JAMA Psychiatry; doi:10.1001/jamapsychiatry.2018.3901. [Online 27 Feb 2019]

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