Researchers reported that maternal use of supplemental folic acid around the time of conception was associated with a 39% lower odds of an autism spectrum disorder — specifically, autistic disorder — in children. The study results are consistent with previous research.
“The study provides an additional reason for pregnant women to take folic acid supplements, and the findings underline the importance of starting early, preferably before the start of pregnancy," study researcher Pål Surén, MD, MPH, of the Norwegian Institute of Public Health in Oslo, Norway, told Psychiatric Annals.
Surén and colleagues examined the association between maternal folic acid use and autism spectrum disorder (ASD) risk in a sample of 85,176 children who were enrolled in the Norwegian Mother and Child Cohort Study. The researchers looked at the effect of folic acid use from 4 weeks before to 8 weeks after the start of pregnancy. The effect of prenatal fish oil supplements was also examined. Logistic regression analyses were used to determine the odds ratios.
At the end of follow-up, 270 children had been diagnosed with an ASD, 114 of whom had autistic disorder. Among children whose mothers used folic acid, 0.1% were diagnosed with autistic disorder vs. 0.21% of children whose mothers’ did not use the supplement. After adjusting for maternal education level, year of birth and parity, the odds ratio for autistic disorder in children whose mothers used folic acid was 0.61 (95% CI, 0.41-0.9). The researchers found no association between folic acid intake and lowered risk for pervasive developmental disorder-not otherwise specified. For Asperger’s syndrome, statistical power was too low.
Prenatal fish oil supplements were not associated with reduced autism risk.
Mothers in the study who used folic acid were more likely of higher socioeconomic status and more health-conscious, according to the researchers, which may have confounded the results. However, fish oil use, which did not lower autism risk, was associated with the same parental characteristics.
Surén and colleagues wrote that the findings do not “establish a causal relation between folic acid use and autistic disorder but provides a rationale for replicating the analyses in other study samples and further investigating genetic factors and other biological mechanisms that may explain the inverse association.”
In an accompany editorial, Robert J. Berry, MD, MPHTM, of the CDC’s Division of Birth Defects and Developmental Disorders, and colleagues wrote that ASDs have been associated with a combination of heterogeneous genetic and environmental risk factors, presenting a major obstacle to researchers.
“It is reassuring that the study by Surén et al found no association between folic acid supplementation and an increased risk for autistic disorder or ASDs,” they wrote. “This should ensure that folic acid intake can continue to serve as a tool for the prevention of neural tube birth defects. The potential for a nutritional supplement to reduce the risk of autistic disorder is provocative and should be confirmed in other populations.”
For more information:
Berry RJ. JAMA. 2013;309:611-613.
Surén P. JAMA. 2013;309:570-577.
Disclosure: One of the study researchers reported receiving payment for lectures at the University of Oslo and the University Agder.