Efficacy of vitamin D supplementation on COPD and asthma control: A systematic review and meta-analysis

Background The role of vitamin D (VD) in the management of chronic ob-structive pulmonary disease (COPD) and asthma remains largely undeter-mined. In the present meta-analysis, we aimed to comprehensively investigate the efficacy of VD in the treatment of COPD and asthma according to the lat-est update.Methods The PubMed, Embase, and Cochrane Library databases were searched from their inception to June 2, 2022. Randomized controlled trials (RCTs) com-paring the efficacy of VD with placebo against COPD or asthma were included.Results A total of 11 RCTs consisting of 1183 COPD patients and 19 RCTs con-sisting of 2025 asthmatic patients were finally included. As for pulmonary func-tion, FEV1/FVC was not changed significantly, while FEV1% was improved in the VD group. In the asthma subgroup, FEV1% was not changed significantly, while FEV1/FVC was improved in the VD group. For the questionnaire and rat-ing scale, the mMRC (modified Medical Research Council) dyspnoea scale score for COPD and ACT (Asthma Control Test) score for asthma were not signifi-cantly changed, while the SGRQ (St. George's Respiratory Questionnaire) score for COPD was improved in the VD group. For inflammation indicators, IL-6 and IL-10 were statistically equivalent between the VD and placebo groups, while IgE, IL-5, and IL-10 (baseline VD deficiency subgroup) were improved in the VD group. The exacerbation, length of hospital stays, and mortality were statistically equivalent between the two groups.Conclusions VD supplementation improved the indicators of asthma and COPD, especially in pulmonary function, SGRQ scores, IL-5, and IgE.Registration The protocol could be found at PROSPERO with the registration number of CRD42020218058.