Efficacy of vitamin D in treatment of inflammatory bowel disease: A meta-analysis

BACKGROUND: Vitamin D (VitD) deficiency is prevalent in patient with inflammatory bowel disease (IBD). Recent studies have found that VitD can induce and maintain IBD remission through antibiosis, anti-inflammatory, and repair of intestinal mucosal barriers, thus improving the patient's disease activity and quality-of-life. The purpose of this meta-analysis is to evaluate the therapeutic effect and safety of VitD in the treatment of IBD. METHODS: Published randomized controlled trials (RCTs) were included from electronic databases (PubMed, Embase, Cochrane library, Web of Science, and so forth). Cochrane handbook was applied to evaluate the methodological quality. The levels of 25(OH)D3, relapse rate, inflammation index, and adverse events were compared between the experimental group and the control group (placebo group). All statistical analyses were directed by Revman 5.3 software and statistical significance was defined as P < .05. RESULTS: Eighteen RCTs involved 908 patients were included. Meta-analysis showed that VitD improved the 25(OH)D3 levels more significantly than the control group (ng/mL, weighted mean deviation [WMD] = 7.85, 95% CI (5.52, 10.18), P < .000001), and compared with lower doses, there were significant differences increasing 25(OH)D3 levels (WMD = 11.19, 95% CI [4.73, 17.65], P = .0007) in high-dose VitD treatment while there was no significant difference in the adverse events between 2 groups (WMD = 1.56, 95% CI [0.74, 3.29], P = .24). VitD reduced the relapse rate more significantly than the control group, but there were no significant differences between the low-dose and high-dose vitamin D treatment. The erythrocyte sedimentation rate (ESR) and high-sensitivity C-reactive protein (hsCRP) of the VitD and the control group showed no statistically significant difference (ESR [mm/h]: WMD = –0.22, 95% CI [–5.73, 5.29], P = .94; hsCRP (mg/dL): WMD = −0.53, 95% CI [–1.68, 0.62], P = .37). CONCLUSIONS: The treatment of VitD in patients with IBD can improve the level of 25(OH)D3 and control the relapse rate of the disease, whose clinical curative effect is more accurate. Thus VitD should be recommended for the treatment of IBD, at least as an adjunctive treatment.