Prenatal vitamins and risk of autism
Taking prenatal folic acid and multivitamins lowers the risk of autism, according to results of a new case-control study. Published in JAMA Psychiatry, the report by Israeli investigators the findings have important public health implications but the mechanisms for the protective action of the supplements have yet to be determined.
A total of 45,300 Israeli children (22,090 girls; 23,210 boys) born between January 1, 2003 and December 31, 2007 were included in the study and followed from birth to January 26, 2015 for risk of autism. Cases were all children diagnosed with autism and controls were a random sample of 33% of all live-born children. Exposure before and during pregnancy to folic acid, multivitamins containing vitamins A, B, C, and D, or any combination thereof was assessed. The authors quantified the association between maternal exposure to the vitamins and relative risk (RR) and 95% confidence intervals (CI) for autism in offspring.
Of the children in the study, 572 (1.3%) were diagnosed with autism. Risk of the disorder was statistically significantly lower in the children whose mothers were exposed to folic acid and/or multivitamins before pregnancy (RR, 03.9; 95% CI, 0.30-0.50; P < .001). A similar reduction in risk was seen with maternal exposure to folic acid and/or multivitamins during pregnancy (RR, 0.27; 95% CI, 0.22-0.33; P < .001). Risk ratios were also similar for maternal exposures to folic acid before pregnancy, to folic acid during pregnancy, to multivitamins before pregnancy, and to multivitamin supplements during pregnancy (all P < .001).
The authors concluded that maternal exposure to folic acids before and during pregnancy reduces risk of autism in offspring and postulated that epigenetic modifications may be among the mechanisms for the association.