A Comprehensive Review on Vitamin D as a Novel Therapeutic Agent in Chronic Obstructive Pulmonary Disease

Vitamin D has been playing an important role in the treatment of lung diseases. The non-calcemic effects of this vitamin and its role in chronic obstructive pulmonary disease (COPD) has drawn significant attention recently. Many studies have been conducted to explore the relationship between the two. We tested the hypothesis that vitamin D can act as an effective therapeutic agent for COPD by reviewing the correlation between the two and effectiveness along with the safety of supplemental vitamin D when used to treat chronic bronchitis and emphysema through clinical trials. An electronic search was conducted using combinations of keywords "vitamin D" and "COPD" from PubMed and Google scholar. Only relevant, human studies of all types were included from the last decade. A total of 36 articles were selected for review. Observational studies indicate a correlation between low serum 25(OH)D levels and obstructive lung disease pathology as well as clinical outcomes. Moreover, clinical trials were aimed to understand the impact of the use of vitamin D in improving disease indexes. These clinical trials used different drug regimes, mode of administration, and intervention duration with contrasting outcomes. Hypovitaminosis D is a common and harmful variant of this group of obstructive lung diseases, and correcting this deficiency can improve exacerbations, inflammation, lung functions, symptoms, and quality of life. These benefits are more prevalent in patients with low baseline serum 25 hydroxyvitamin D(25(OH)D) levels. Peroral is the most frequently used route of drug administration, however, further work is required to explore the pharmacological properties of vitamin D. There was not enough literature available about the safety of the drug of intervention.