Figure 2From: Severe vitamin D deficiency is associated with frequent exacerbations and hospitalization in COPD patients Levels of vitamin D (log-scale) in COPD subjects divided according to the number of exacerbations the year previous to the measurements of vitamin D levels (A) and the proportion of subjects with severe vitamin D deficiency (<10 ng/mL) in COPD subjects divided according to the number of exacerbations the year previous to the measurements of vitamin D levels (B). Back to article page