title: Vitamin D level, respiratory tract infections, and controlled trials.
authors: Harri
authors: H
authors: Hemilä
mesh_terms: D001205:Ascorbic Acid / Q000008:administration & dosage / Q000097:blood; D004305:Dose-Response Relationship, Drug; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D012141:Respiratory Tract Infections / Q000097:blood / Q000517:prevention & control*; D016896:Treatment Outcome; D014807:Vitamin D / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D; D001205:Ascorbic Acid