ABSTRACT
<p><b>OBJECTIVE</b>To examine serum 25-hydroxyvitamin D levels in children with autism spectrum disorders (ASD) and to explore the relationship between vitamin D level and ASD.</p><p><b>METHODS</b>Serum levels of 25-hydroxyvitamin D levels were determined by the HPLC-MS/MS method in 117 children with newly diagnosed ASD and 109 healthy controls. Vitamin D status were classified into normal (>30 ng/mL), insufficiency (10-30ng/mL) and deficiency (<10 ng/mL) according to 25-hydroxyvitamin D levels.</p><p><b>RESULTS</b>Serum level of 25-hydroxyvitamin D (19±9 ng/mL)in children with ASD was significantly lower than that in healthy controls (36±13 ng/mL; P<0.01). The rate of vitamin D insufficiency plus deficiency in the ASD group was significantly higher than in the control group (89.7% vs 52.3%; P<0.01).</p><p><b>CONCLUSIONS</b>Vitamin D insufficiency or deficiency is common in children with ASD and might be as one of the environmental or genetic factors for ASD.</p>