"Mothers of children with autism were significantly 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," said Rebecca J. Schmidt, assistant professor in the Department of Public Health Sciences in the UC Davis School of Medicine and the study's lead author.
Consuming prenatal vitamins may be especially effective for genetically susceptible mothers and their children. For women with a particular high-risk genetic make up who reported not taking prenatal vitamins, the estimated risk of having a child with autism was as much as seven times greater than in women who did report taking prenatal vitamins and who had more favorable gene variants, the study found.
The authors postulate that folic acid, the synthetic form of folate or vitamin B9, and the other B vitamins in prenatal supplements, likely protect against deficits in early fetal brain development. Folate is known to be critical to neurodevelopment and studies have found that supplemental folic acid has the potential to prevent up to 70 percent of neural tube defects, the authors said.
"This finding appears to be the first example of gene-environment interaction in autism," said Irva Hertz-Picciotto, professor and chief of the division of environmental and occupational health in the Department of Public Health Sciences in the UC Davis School of Medicine.
"It is widely accepted that autism spectrum disorders are the result of multiple factors, that it would be extremely rare to find someone who had a single cause for this behavioral syndrome. Nevertheless, previous work on genes has generally ignored the possibility that genes may act in concert with environmental exposures," said Hertz-Picciotto, the study's senior author and a researcher affiliated with the UC Davis MIND Institute.
To conduct the study, researchers collected data from approximately 700 Northern California families with 2- to 5-year-old children who had autism or typical development and were participants in the Childhood Autism Risk from Genetics and the Environment (CHARGE) study between from January 2003 to December 2009. All children were born in California and came from families that spoke either English or Spanish. The autism diagnoses were confirmed through testing at the UC Davis MIND Institute.
Women who participated in the CHARGE study were asked via telephone whether they took prenatal vitamins, multivitamins or other supplements at any time during the three months prior to and during their pregnancies and during breastfeeding. If the respondent said she had taken vitamins, she was further asked what type she took, at what dosage and frequency and during which months of pregnancy she consumed them.
MEDICA.de; Source: University of California - Davis Health System