Association of Maternal Use of Folic Acid and Multivitamin Supplements Before and During Pregnancy With the Risk of ASD in Offspring (2018)

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Stephen Z. Levine, PhD; Arad Kodesh, MD; Alexander Viktorin, PhD; Lauren Smith, BA; Rudolf Uher, MD, PhD; Abraham Reichenberg, PhD; Sven Sandin, PhD

JAMA Psychiatry. Published online January 3, 2018.

Key Points
Question Does maternal folic acid and/or multivitamin supplement use before and/or during pregnancy increase the risk of autism spectrum disorder in offspring?

Findings In this case-control cohort study of 45 300 offspring, statistically significant associations between maternal vitamin supplement use before and/or during pregnancy and reduced risk of autism spectrum disorder in offspring were observed.

Meaning A reduced risk of autism spectrum disorder in children born to women who used the specified vitamin supplements before and during pregnancy has important public health implications; possible mechanisms include epigenetic modifications.

Abstract
Importance The association of maternal use of folic acid and multivitamin supplements before and during pregnancy with the risk of autism spectrum disorder (ASD) in offspring is unclear.

Objective To examine the associations between the use of maternal folic acid and multivitamin supplements before and during pregnancy and the risk of ASD in offspring.

Design, Setting, and Participants A case-control cohort study of 45 300 Israeli children born between January 1, 2003, and December 31, 2007, were followed up from birth to January 26, 2015, for the risk of ASD. The cases were all children diagnosed with ASD and the controls were a random sample of 33% of all live-born children.

Exposures Maternal vitamin supplements were classified for folic acid (vitamin B9), multivitamin supplements (Anatomical Therapeutic Chemical A11 codes vitamins A, B, C, and D), and any combination thereof exposed in the intervals before and during pregnancy.

Main Outcomes and Measures The association between maternal vitamin supplementation and the risk of ASD in offspring was quantified with relative risks (RRs) and their 95% CIs fitting Cox proportional hazards regression models adjusted for confounders. Sensitivity analyses were performed to test the robustness of the results.

Results Of the 45 300 children in the study (22 090 girls and 23 210 boys; mean [SD] age, 10.0 [1.4] years at the end of follow-up), 572 (1.3%) received a diagnosis of ASD. Maternal exposure to folic acid and/or multivitamin supplements before pregnancy was statistically significantly associated with a lower likelihood of ASD in the offspring compared with no exposure before pregnancy (RR, 0.39; 95% CI, 0.30-0.50; P < .001). Maternal exposure to folic acid and/or multivitamin supplements during pregnancy was statistically significantly associated with a lower likelihood of ASD in offspring compared with no exposure during pregnancy (RR, 0.27; 95% CI, 0.22-0.33; P < .001). Corresponding RRs were estimated for maternal exposure to folic acid before pregnancy (RR, 0.56; 95% CI, 0.42-0.74; P = .001), maternal exposure to folic acid during pregnancy (RR, 0.32; 95% CI, 0.26-0.41; P < .001), maternal exposure to multivitamin supplements before pregnancy (RR, 0.36; 95% CI, 0.24-0.52; P < .001), and maternal exposure to multivitamin supplements during pregnancy (RR, 0.35; 95% CI, 0.28-0.44; P < .001). The results generally remained statistically significant across sensitivity analyses.

Conclusions and Relevance Maternal exposure to folic acid and multivitamin supplements before and during pregnancy is associated with a reduced risk of ASD in the offspring compared with the offspring of mothers without such exposure.

https://jamanetwork.com/journals/jamapsychiatry/fullarticle/2667432

 

[Woolie]

Is it just me who's a bit sceptical about this? There are a few things niggling me. One is that its an observational study, and there might be lots of factors that determine whether or not a mother will use folic acid. The second is that ASD is a low frequency occurrence, so very small variations in incidence can impact on association rates quite substantially.

My third niggle is with the deficit model of ASD. Sure, having moderate to severe ASD is not something anyone would wish for. But just because some types of variation are awful for the sufferers does not necessarily mean that something "went wrong" during gestation or afterwards. What if the ASD spectrum is something we all vary on, and its a matter of parents, genetics and luck where we all end up getting placed on it? There might not be any "bad" event or set of circumstances that makes one "susceptible".

I think a lot of people with mild ASD also find the deficit model offensive. They see themselves as different, but as having unique strengths. I think so too. Where would physics be if we eradicated all cases of mild ASD? We'd lose a lot of talent in that area, because I don't think the association between mild ASD and physics talent is coincidental. Some types of minds are just well suited to certain things.