Objective: The aim of this study was to examine the association between maternal serum vitamin D status in first trimester and risk of ASD at age 3-7years in the offspring.
Methods: Using a case-control design, 68 children diagnosed with ASD and 68 sex and age matched typically-developing children were included. Archived maternal blood samples from the first trimester of pregnancy (11-13weeks gestational age) were identified for those participants. Maternal serum levels of 25 hydroxyvitamin D3 [25(OH) D], unmetabolized folic acid (FA), vitamin B12, homocysteine (HCY) and High Sensitivity C Reactive protein (CRP) were measured from those samples. We examined the associations between those factors in pregnancy and diagnosis of ASD with logistic regression using SPSS.
Results: Mothers in autistic group had significantly lower maternal serum levels of 25(OH) D than in typically-developing group [19.2(IQR: 15.8-22.9)ng/ml vs. 24.3(19.3-27.3)ng/ml, P<0.001], with 55.9% and 29.4% being vitamin D deficient, respectively (P<0.001). Levels of 25(OH) D increased with decreasing severity of ASD as defined by the CARS score (r=-0.302, P<0.001). Maternal first trimester serum levels of 25(OH) D in the lower 3 quartiles (quartile 1, 2, 3) (compared to the highest quartile) was associated with increased odds of ASD diagnosis in offspring [OR (95% CI) Q1: 1.36(0.84-2.58, P=0.25); Q2: 2.68(1.44-4.29, P=0.006); Q3:3.99(2.58-7.12, P<0.001)].
Conclusions: Lower first trimester maternal serum levels of 25(OH) D were associated with increased risk of developing autism in offspring. If these findings are confirmed, this may present an opportunity for prenatal intervention to reduce the risk for ASD.
Keywords: 25(OH) D; Autism spectrum disorders; Maternal; Vitamin D.
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