Maternal folic acid and micronutrient supplementation is associated with vitamin levels and symptoms in children with autism spectrum disorders

Maternal Dietary Factors and the Risk of Autism Spectrum Disorders: A Systematic Review of Existing Evidence

“…Overall, strong associations consistent with clinically impairing symptoms were not observed across these studies, though several studies reported modest inverse associations between the dietary factor and ASD‐related traits. An additional study (the Tan et al Chinese case–control study further described below within the FA and other nutrients sections) suggested increases in ASD‐related traits according to the SRS in those without FA and micronutrient supplement use but did not conduct adjusted analyses [Tan et al, 2020].…”

“…In addition, one investigation examined micronutrient supplementation in unadjusted analyses. This Chinese case control study (which also examined FA use) reported increased odds of ASD, as well as greater autism‐related traits according to the SRS, in children of mothers retrospectively reporting no micronutrient supplementation use compared to those reporting use [Tan et al, 2020]. A prospective cohort study, previously mentioned in the FA section, also examined self‐reported maternal use of other vitamins/minerals supplements from 4 weeks before to 8 weeks after pregnancy in the exploratory analyses and reported no statistically significant association with risk of ASD [Suren et al, 2013].…”

“…To date, a total of 15 studies evaluated the association between maternal FA and ASD: 12 of these utilized self‐reported FA supplementation use (9 prospective cohort studies, 2 of which relied on medical dispensation records, and 3 case–control studies with retrospective reporting), 4 used maternal folate biomarkers from samples collected during pregnancy (3 prospective cohort studies and one case–control study), and 1 (a prospective cohort) used both reported supplementation and biomarkers [Bjork et al, 2018; Levine et al, 2018; Raghavan et al, 2018; Schmidt et al, 2012; Schmidt, Iosif, et al, 2019; Steenweg‐de Graaff, Ghassabian, Jaddoe, Tiemeier, & Roza, 2015; Suren et al, 2013; Tan et al, 2020]. Several studies are drawn from the same study population; 2 came from the DNBC cohort [Strom et al, 2018; Virk et al, 2016], and 2 from the MoBa cohort [Bjork et al, 2018; Suren et al, 2013].…”

“…Eleven of these 15 studies were discussed in detail in a recent systematic review [M. Li et al, 2019]. Thus, we provide somewhat greater information below on the 4 more recent studies [Bjork et al, 2018;Egorova et al, 2020;Sharman Moser et al, 2019;Tan et al, 2020].…”

“…Only a handful of studies considered ASD outcomes according to both diagnosis and quantitative traits, as may help to inform strength of associations across the range of the autism spectrum [L. Gao, Cui, et al, 2016;Y. M. Li et al, 2018;Schmidt et al, 2011Schmidt et al, , 2012Schmidt et al, , 2014Schmidt, Niu, et al, 2019;Tan et al, 2020;Whitehouse et al, 2013]. Finally, while a number of studies considered certain other dietary factors that may influence associations in their analyses [Braun et al, 2014;Chen et al, 2016;House et al, 2018;Huang et al, 2020;Julvez et al, 2016;Y.…”