Effect of vitamin D on infection and inflammation in patients with cystic fibrosis: a systematic review and meta-analysis

BackgroundCystic fibrosis (CF) is a genetic disorder in which the respiratory system gets clogged with mucus leads to progressive lung damage. There is no known cure for CF but several treatments to manage symptoms and reduce complications. Vitamin D deficiency is common in CF associated with increased infection and inflammation. This systematic review and meta-analysis will evaluate the effectiveness of vitamin D treatment in reducing respiratory tract infection and inflammation in patients with CF. MethodsRandomized and quasi-randomised studies in CF patients with control groups will be identified. The antibacterial activity of vitamin D supplementation will help in reducing respiratory tract infection and inflammation in CF. Overall effects of vitamin D in terms of infection and inflammatory markers such as C-reactive protein, inflammatory cytokine interleukin (IL)-6, IL-8, IL-17, IL-23, antimicrobial peptide (LL-37), lung function defined by forced expiratory volume in 1 second (FEV1) %, other assessed respiratory parameters will be calculated using random-effect models. Study quality will be assessed using RoB 2 - A revised Cochrane Risk of Bias tool for randomised trials. The overall quality of evidence for each outcome will be summarised according to the Grading of Recommendations Assessment, Development, and Evaluations (GRADE) framework.