Maternal vitamin D deficiency and the risk of autism spectrum disorders: population-based study

BackgroundMaternal vitamin D deficiency may increase risk of autism spectrum disorder (ASD), but direct evidence is lacking.AimsTo clarify the relationship between maternal vitamin D deficiency and offspring risk of ASD with and without intellectual disability.MethodUsing a register-based total population study (N=509 639), we calculated adjusted odds ratios (aORs) and 95% confidence intervals (CIS) of ASD with and without intellectual disability in relation to lifetime diagnoses of maternal vitamin D deficiency. Although rare, such deficiency was associated with offspring risk of ASD with, but not without, intellectual disability (aORs 2.51, 95% CI 1.22–5.16 and 1.28, 0.68–2.42). Relationships were stronger in non-immigrant children.ConclusionsIf reflecting associations for prenatal hypovitaminosis, these findings imply gestational vitamin D substitution as a means of ASD prevention.