Background: The vitamin D role in bone metabolism is well known; however, recent evidence suggests the impact of vitamin D in immune modulation and its implications in immune-mediated diseases, including inflammatory bowel disease (IBD).
Method: We performed a systematic review with meta-analysis by a specific protocol (PROSPERO: CRD42022311184; March 2022, https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=311184). Randomized clinical trials involving IBD patients treated with vitamin D supplementation, compared with placebo, that evaluated the risk of clinical relapse and disease activity were included. Literature search was performed using Medline, Scopus, and Cochrane CENTRAL through January 2022.
Results: Out of 1448 articles, 12 (11 full-texts and 1 abstract) were included. Seven randomized clinical trials reported data on the clinical relapse as dichotomous outcome, while 7 studies reported data on disease activity expressed as continuous variables. The pooled risk ratio of clinical relapse was 0.64 (95% confidence interval, 0.46-0.89; I2 = 25%) among 458 IBD patients. However, this seems to be solid only in Crohn's disease (CD) patients. In fact, only 2 studies, involving 67 patients with ulcerative colitis, were included in the analysis. CD patients in clinical remission had a strong significant risk reduction in clinical relapse (risk ratio, 0.47; 95% confidence interval, 0.27-0.82; I2 = 0%), suggesting that it could be a specific subgroup with maximum clinical benefit of vitamin D supplementation.
Conclusions: This meta-analysis shows that vitamin D supplementation can reduce the risk of clinical relapse in IBD patients, especially in CD patients in clinical remission. In a subgroup analysis, it was not significant (due to small number of studies and low number of patients), and well-powered studies are needed, in particular for ulcerative colitis patients.
Keywords: Crohn’s disease; IBD; inflammatory bowel disease; ulcerative colitis; vitamin D.
This article is a systematic review with meta-analysis of randomized clinical trials involving inflammatory bowel disease patients treated with vitamin D supplementation, compared with placebo. We aim to assess the risk of clinical relapse or disease activity among these patients.
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