A study published in The Journal of the American Medical Association shows that consuming folic acid during pregnancy may be associated with a lower risk of autistic disorder in their children.
The study sample was 85,176 children (born 2002–2008) from the Norwegian Mother and Child Cohort Study. By the end of follow-up on March 31, 2012, the age range was 3.3 years through 10.2 years with a mean of 6.4 years. Folic acid use increased by year of birth, going from 43% in 2002 to 84% in 2008.
The researchers found that of the 61,042 children whose mothers took folic acid supplements, 64, or 0.1%, had autistic disorder. Of the 24,134 children whose mothers did not take folic acid supplements, 50, or 0.21%, had autistic disorder. Use of folic acid supplements was associated with higher socioeconomic status and more health-conscious maternal behavior patterns in the study sample. The researchers noted that they cannot exclude the possibility that some portion of the inverse association represents residual, unmeasured confounding. However, if residual confounding was substantial, we would have expected to find a lowering of risk associated with fish oil supplement use as well, because the use of fish oil was associated with the same parental characteristics in the study sample. No association with reduced risk of autistic disorder was found with fish oil.
“Although these findings cannot establish causality, they do support prenatal folic acid supplementation,” the researchers concluded.