The present study confirms that the proportion of vitamin D deficiency was higher in the NH group than in controls, and rs12785878 (NADSYN1/DHCR7) and rs10877012 (CYP27B1) are correlated with NH risk and vitamin D deficiency, which supports the biologic explanation of a connection between the vitamin D metabolic pathway genes polymorphisms and NH risk. This evidence concerns the gene NADSYN1 and vitamin D deficiency.