Liu J, Dong YQ, Yin J, et al. - Researchers determined the link between serum vitamin D and lung function in asthma patients, via this meta-analysis of all the relevant published observational studies identified from major databases, including OVID, MEDLINE, Web of Science and PUBMED. They used Review Manager 5.3.5 to conduct all meta-analyses. Lower forced expiratory volume in 1 s (FEV1) and FEV1% was observed in asthma patients with low vitamin D levels vs those with sufficient vitamin D levels, as revealed in this quantitative synthesis. They found a positive link between vitamin D and FEV1, FEV1%, forced vital capacity (FVC), FEV1/FVC, and the asthma control test. Significance of the positive correlation between vitamin D and lung function persisted in both children and adults. Experts concluded a possible positive correlation of serum vitamin D levels with lung function in asthma patients.