No evidence was found of interactions between serum vitamin D and the Taq1 polymorphism in the vitamin D receptor (VDR) nor the polymorphisms in vitamin D binding protein on CD risk at multiple time points in a prospective cohort study of US military personnel.55 However, significant interactions between VCR polymorphisms (Fokl, Apal, and Taql) and vitamin D deficiency in relation to CD risk were observed in a Chinese case-control study.56 No interaction was found between the Bsml genotype in VDR and vitamin D deficiency on CD risk in this cohort.56 Here, GC is linked to vitamin D deficiency.