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Environmental Factor

June 2011

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Early prenatal vitamins may decrease incidence of autism

By Ed Kang
June 2011

Irva Hertz-Picciotto, Ph.D., MPH

"The good news is that if this finding is replicated, it will provide an inexpensive, relatively simple action that women can take to reduce risks for their child, which is to take prenatal vitamins as early as possible in a pregnancy and even when planning for pregnancy," said Picciotto, the study's senior author and a researcher affiliated with the UC Davis MIND Institute. (Photo courtesy UC Davis)

Rebecca Schmidt, Ph.D.

Schmidt discovered associations that suggest the time around conception might be particularly sensitive to environmental risk factors for autism. (Photo courtesy UC Regents)

A new study by NIEHS-funded researchers indicates that mothers of children with autism were less likely than those of typically developing children to report having taken prenatal vitamins during the three months before and the first month of pregnancy. There was, however, no observed change in associated risk for autism when prenatal vitamins were taken after the first month of pregnancy or when multivitamins were taken at any time.

In the first study (,_One_carbon_Metabolism_Gene.99561.aspx) Exit NIEHS to link maternal intake of vitamins to autism risk, researchers at the University of California (UC), Davis Medical Investigation of Neurodevelopmental Disorders (MIND) Institute ( Exit NIEHS examined prenatal vitamin intake between mothers of children with autism and those of typically developing children. Mothers were asked about their vitamin use during the three months prior to pregnancy through the breastfeeding period.

"Women who did not take daily prenatal vitamins early were nearly twice as likely to have a child with an autism spectrum disorder as women who did take the supplements," said Rebecca Schmidt, Ph.D., assistant professor in the Department of Public Health Sciences in the UC Davis School of Medicine and the study's lead author. "The associated risk rose to seven times as great when combined with a high-risk genetic make-up."

Folic acid, B vitamins critical to neurodevelopment

"While the cause of autism is still unknown, this study provides more clues in our search for answers," said Linda Birnbaum, Ph.D., director of NIEHS, which provided a majority of the funding for the study.

Prenatal vitamins generally have higher levels of iron, vitamins B6 and B12, and twice as much folic acid (folate) as multivitamins. These nutrients are known to be critical to neurodevelopment, and the study's authors suggest a protective effect against deficits in early fetal brain development.

Approximately 700 participants, who included children with autism and typically developing children, were recruited from the larger Childhood Autism Risks from Genetics and the Environment (CHARGE) study, a population-based, case-control study of Northern California families.

Autism, according to the U.S. Centers for Disease Control and Prevention, affects about one in 110 children in the United States and is a pervasive developmental disorder marked by poor verbal and communication skills, repetitive behaviors, and difficulties in forming social connections.

The study was supported by grants from NIEHS, including funding provided by the American Recovery and Reinvestment Act of 2009. Additional funding was also provided by the U.S. Environmental Protection Agency and the UC Davis MIND Institute.

Citation: Schmidt RJ, Hansen RL, Hartiala J, Allayee H, Schmidt LC, Tancredi DJ, Tassone F, Hertz-Picciotto I (,_One_carbon_Metabolism_Gene.99561.aspx) Exit NIEHS. 2011. Prenatal vitamins, functional one-carbon metabolism gene variants, and risk for autism in the CHARGE study. Epidemiology; doi: 10.1097/EDE.0b013e31821d0e30 [Online 23 May 2011].

(Ed Kang is a public affairs specialist in the Office of Communications and Public Liaison and a regular contributor to the Environmental Factor.)

Public television showcases challenges and new developments in the field of autism

Irva Hertz-Picciotto, Ph.D.( Exit NIEHS and several colleagues from the MIND Institute were among the national experts featured on the six-part Public Broadcasting System series "Autism Now (," Exit NIEHS which aired beginning April 18. Produced and narrated by Robert McNeil, the episodes are available for viewing on the PBS "News Hour" website( Exit NIEHS online.

The series also features an extended interview( Exit NIEHS with Hertz-Picciotto on what may be behind the rising incidence of autism

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