Objective: The purpose of this study was to determine whether vitamin D receptor (VDR) gene polymorphisms influence risk of colorectal adenoma.
Methods: Polymorphisms in the 5' and 3' ends of the VDR gene were genotyped for 373 colorectal adenoma cases and 394 controls.
Results: Overall, there was no significant association between the 5' (FokI) or the 3' (BsmI) polymorphisms and adenoma risk. However, risk of large (>1 cm) adenomas decreased with increasing copies of the FokI f allele (p = 0.04). Compared to the FF genotype, odds ratios for the Ff and ff genotypes were 0.79 (95% CI 0.44-1.41) and 0.32 (95% CI 0.11-0.91), respectively. FokI genotype was more strongly related to large adenoma risk among subjects with low dietary calcium intake (ORFf=0.48; 95% CI 0.17-1.3; ORff=0.21: 95% CI 0.04-1.3), low dietary vitamin D intake (ORFf=0.25; 95% CI 0.09-0.69; ORff= 0.22; 95% CI 0.04-1.2), or dark skin color (ORFf=0.66; 95% CI 0.27-1.6; ORff=0.10; 95% CI 0.01-1.0).
Conclusion: These results suggest that VDR FokI genotype influences development of colorectal adenomas. and that the effect may be modified by calcium and vitamin D status.