Vitamin D Supplementation Did Not Prevent Adenomas or Serrated Lesions
Douglas K. Rex, MD, FASGE, reviewing Song M, et al. Clin Gastroenterol Hepatol 2020 Feb 13.
There is an association between vitamin D levels and colorectal cancer, but there is not yet clear evidence that supplementation prevents colorectal cancer, polyps, or adenomas.
In this study, investigators looked at rates of incident adenomas and serrated lesions among patients undergoing surveillance colonoscopy within a large randomized controlled trial of vitamin D supplementation. There were 25,871 adults participating who received 2000 IU of vitamin D3 and 1 g of marine n-3 fatty acid or placebo. Within the subjects, 2852 reported a diagnosis of colorectal polyps on the questionnaire, and 53% said they were asked to return for repeat colonoscopy in 5 years. Medical records were pursued from 999 individuals. Of the study participants, conventional adenomas occurred in 308 patients in the vitamin D group and 287 patients in the placebo group. In addition, of patients with serrated lesions (hyperplastic polyp, traditional serrated adenoma, and sessile serrated lesions), 172 cases were in the vitamin D group and 169 in the placebo group. The mean time between randomization and polyp diagnosis was just over 3 years in both groups.
COMMENT
In current clinical practice, checking vitamin D levels is ubiquitous, many patients have low levels, and supplementation is common. Patients often ask in the recovery room what they can do to prevent further polyp development, and one of my suggestions is to keep a high normal vitamin D level. I’m not likely to stop giving that recommendation, given the association of low vitamin D levels with bad outcomes, including GI outcomes. Further, vitamin D supplementation is safe as long as it does not lead to sustained high serum values. However, there is no experimental evidence that vitamin D supplementation will reduce the chance of polyps at the next colonoscopy.
Note to readers: At the time we reviewed this paper, its publisher noted that it was not in final form and that subsequent changes might be made.
Douglas K. Rex, MD, FASGE
CITATION(S)
Song M, Lee IM, Manson JE, et al. No association between vitamin D supplementation and risk of colorectal adenomas or serrated polyps in a randomized trial. Clin Gastroenterol Hepatol 2020 Feb 13. (Epub ahead of print) (https://doi.org/10.1016/j.cgh.2020.02.013)
