Vitamin D deficiency: What does it mean for chronic obstructive pulmonary disease (COPD)? a compherensive review for pulmonologists.

OBJECTIVES: Vitamin D deficiency and Chronic Obstructive Pulmonary Disease (COPD) are both under-recognized health problems, world-wide. Although Vitamin D has long been known for calcemic effects it also has less known noncalcemic effects. Recent data have shown that Vitamin D deficiency is highly prevalent in patients with COPD and correlates with forced expiratory volume in one second (FEV1 ) and FEV1 decline. The objective of this work was to review the current literature on vitamin D deficiency in relation with COPD. DATA SOURCE: A literature search, using the words "vitamin D" and "COPD", was undertaken in Pubmed database.
RESULTS: The noncalcemic effects of vitamin D relating with COPD may be summarised as increasing antimicrobial peptide production, regulation of inflammatory response and airway remodelling. Vitamin D inhibits the production of several proinflammatory cytokines and leads to suppression Th1 and Th17 responses which may be involved in the pathogenesis of COPD. Vitamin D insufficiency may also contribute to chronic respiratory infections and airway colonization so returning vitamin D concentrations to an optimal range in patients with COPD might reduce bacterial load and concomitant exacerbations.Vitamin D is also important for COPD-related comorbodities such as osteoporosis, muscle weakness and cardiovascular diseases. Data about the effect of Vitamin D supplementation on those comorbidities in relation with COPD are been scarce.
CONCLUSION: Improving the blood level of Vitamin D into the desired range may have a beneficial effect bones and muscles, but more studies are needed to test to test that hypothesis.