There is intense interest in identifying modifiable risk factors associated with autism-spectrum disorders (ASD). Autism-related traits, which can be assessed in a continuous fashion, share risk factors with ASD, and thus can serve as informative phenotypes in population-based cohort studies. Based on the growing body of research linking gestational Vitamin D deficiency with altered brain development, this common exposure is a candidate modifiable risk factor for ASD and autism-related traits. The association between gestational Vitamin D deficiency and a continuous measure of autism-related traits at ∼6 years (Social Responsiveness Scale; SRS) was determined in a large population-based cohort of mothers and their children (n=4229). 25-hydroxyVitamin D (25OHD) was assessed from maternal mid-gestation sera and from neonatal sera (collected from cord blood). Vitamin D deficiency was defined as 25OHD concentrations less than 25 nmol l-1. Compared with the 25OHD sufficient group (25OHD>50 nmol l-1), those who were 25OHD deficient had significantly higher (more abnormal) SRS scores (mid-gestation n=2866, β=0.06, P<0.001; cord blood n=1712, β=0.03, P=0.01). The findings persisted (a) when we restricted the models to offspring with European ancestry, (b) when we adjusted for sample structure using genetic data, (c) when 25OHD was entered as a continuous measure in the models and (d) when we corrected for the effect of season of blood sampling. Gestational Vitamin D deficiency was associated with autism-related traits in a large population-based sample. Because gestational Vitamin D deficiency is readily preventable with safe, cheap and accessible supplements, this candidate risk factor warrants closer scrutiny.,
Molecular Psychiatry
Erasmus MC: University Medical Center Rotterdam

Vinkhuyzen, A.A.E. (A. A.E.), Eyles, D.W. (D. W.), Burne, T. H., Blanken, L., Kruithof, C., Verhulst, F., … McGrath, J.J. (J. J.). (2018). Gestational Vitamin D deficiency and autism-related traits: The Generation R Study. Molecular Psychiatry, 23(2), 240–246. doi:10.1038/mp.2016.213