In conclusion, COPD patients had an increased risk for having
vitamin D deficiency, and the relationship between lung function
and systemic levels of vitamin D was almost linear even after
adjustment for a large number of known and potential confounders.
Future longitudinal studies are warranted to assess the
predictive effect of levels of vitamin D on decline in lung function,
risk for depression, exacerbation frequency, and changes in body
composition in patients with COPD.