Background: As indoor activity increases with modern lifestyles changes, reduced exposure to sunlight may lead to reduced vitamin D synthesis. Previous studies demonstrated that increased vitamin D level is associated with decreased risk of colon cancer; therefore, this study attempted to determine the association between vitamin D and colon polyps, which may be precancerous lesions, in participants who underwent colonoscopy exams.
Results: About 50% of participants had colorectal polyps (hyperplastic polyp, n=4,864; adenomatous polyp, n=10,470; adenocarcinoma, n=24). There were no significant associations between vitamin D categories and colorectal polyp and colorectal cancer. However, when further analyzing by type of polyp, the risk of hyperplastic polyps significantly decreased with increasing vitamin D levels (P for trend=0.006).
Conclusion: We did not find evidence for an association between vitamin D and overall colorectal polyps; however, we observed a trend for decreased odds of hyperplastic polyps with increased vitamin D levels in comparison to vitamin D deficient subjects.