Polymorphisms of the Vitamin D Receptor Gene in Crohn Disease

Introduction Crohn disease (CD) and ulcerative colitis (UC) are chronic inflammatory conditions of the gastrointestinal tract. Studies have shown that polymorphisms of the vitamin D receptor (VDR) gene may help elucidate the pathogenesis of CD. Objectives To analyze the role of VDR gene polymorphisms (ApaI, BsmI, FokI, and TaqI) in the development of CD. Methods The present study is a systematic review with meta-analysis. a total of 50 articles in English and Portuguese published from 2000 to 2020 were selected from 3 databases. The relationship between CD and the VDR gene was addressed in 16 articles. Results The TaqI polymorphism was analyzed in 3,689 patients and 4,645 control subjects (odds ratio [OR] = 0.948; 95% confidence interval [95%CI] = 0.851–1.056; p = 0.3467). The ApaI polymorphism was studied in 3,406 patients and 4,415 control subjects (OR = 1,033; 95%CI = 0.854–1.250; p = 0.7356). For FokI polymorphism, there were 2,998 patients and 4,146 control subjects (OR = 0.965; 95%CI = 0.734–1.267; p = 0.7958). Lastly, the BsmI polymorphism was analyzed in 2,981 patients and 4,477 control subjects (OR = 1,272; 95%CI = 0.748–2.161; p = 0.3743). Conclusion These four VDR gene polymorphisms were not associated with CD. Therefore, further studies with larger samples are required to corroborate or rectify the conclusions from the present meta-analysis.