The Role of Vitamin D in Chronic Obstructive Pulmonary Disease: Mechanisms and Clinical Implications

Purpose of Research: This review synthesizes current evidence on vitamin D's pathophysiological role in chronic obstructive pulmonary disease (COPD), emphasizing its potential as an adjunctive therapy to reduce exacerbations, improve lung function, and address the gaps in mechanistic and translational understanding. Major Findings: COPD is a diverse lung inflammatory condition marked by abnormal airflow restriction. Recent evidence highlights vitamin D deficiency as a modifiable risk factor correlating with increased exacerbations, accelerated lung function decline, and systemic complications. It is synthesized via sunlight exposure or absorbed through dietary intake and exerts its pleiotropic effects through the active metabolite 1,25-dihydroxy vitamin D. This active metabolite binds to vitamin D receptors throughout the body in cells that are involved in calcium and bone metabolism, immunomodulation, and many other tissues. Via these mechanisms it is implicated in potentially mitigating acute exacerbations of COPD. Further, its deficiency may contribute to skeletal muscle dysfunction, osteoporosis, and the cardiovascular comorbidities seen in COPD patients. While observational studies link low vitamin D levels to poorer clinical outcomes in COPD, clinical trials on supplementation remain inconclusive. Conclusions: This review consolidates understanding of vitamin D's role in COPD pathophysiology and highlights its significant therapeutic potential to improve clinical outcomes. Definitive evidence from robust clinical trials is needed to establish optimal dosing, efficacy and translating the evidence into clinical practice.