title: Severe vitamin D deficiency: a biomarker of exacerbation risk?
authors: Nele
authors: N
authors: Heulens
authors: Marc
authors: M
authors: Decramer
authors: Wim
authors: W
authors: Janssens
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D029424:Pulmonary Disease, Chronic Obstructive / Q000209:etiology*; D014807:Vitamin D / Q000031:analogs & derivatives*; D014808:Vitamin D Deficiency / Q000150:complications*
chemical_list: D014807:Vitamin D