Figure 1From: 25-hydroxyvitamin D deficiency, exacerbation frequency and human rhinovirus exacerbations in chronic obstructive pulmonary disease 25-hydroxyvitamin D levels in COPD patients in summer and winter in those on and not on calcium and 25-hydroxyvitamin D supplementation. Data are presented as median, with the boxes representing the interquartile range and the whiskers representing SD. â—‹: extreme outliers.Back to article page