title: Prevention of urinary tract infections with vitamin D supplementation 20,000 IU per week for five years. Results from an RCT including 511 subjects.
abstract: BACKGROUND
  In observational studies vitamin D deficiency is associated with increased risk of infections, whereas the effect of vitamin D supplementation in randomized controlled trials is non-conclusive.
  
  
  METHODS
  Five hundred and eleven subjects with prediabetes were randomized to vitamin D3 (20,000 IU per week) versus placebo for five years. Every sixth month, a questionnaire on respiratory tract infections (RTI) (common cold, bronchitis, influenza) and urinary tract infection (UTI) was filled in.
  
  
  RESULTS
  Mean baseline serum 25-hydroxyvitamin D (25(OH)D) level was 60 nmol/L. Two hundred and fifty-six subjects received vitamin D and 255 placebo. One hundred and sixteen subjects in the vitamin D and 111 in the placebo group completed the five-year study. Eighteen subjects in the vitamin D group and 34 subjects in the placebo group reported UTI during the study (p < 0.02), whereas no significant differences were seen for RTI. The effect on UTI was most pronounced in males. The effect of vitamin D on UTI was unrelated to baseline serum 25(OH)D level.
  
  
  CONCLUSIONS
  Supplementation with vitamin D might prevent UTI, but confirmatory studies are needed.
authors.affiliation: a Department of Clinical Medicine , Tromsø Endocrine Research Group, UiT The Arctic University of Norway , Tromsø , Norway ;|b Division of Internal Medicine , University Hospital of North Norway , Tromsø , Norway ;
authors.forename: Rolf
authors.initials: R
authors.lastname: Jorde
authors.affiliation: a Department of Clinical Medicine , Tromsø Endocrine Research Group, UiT The Arctic University of Norway , Tromsø , Norway ;|b Division of Internal Medicine , University Hospital of North Norway , Tromsø , Norway ;
authors.forename: Stina T
authors.initials: ST
authors.lastname: Sollid
authors.affiliation: a Department of Clinical Medicine , Tromsø Endocrine Research Group, UiT The Arctic University of Norway , Tromsø , Norway ;|b Division of Internal Medicine , University Hospital of North Norway , Tromsø , Norway ;
authors.forename: Johan
authors.initials: J
authors.lastname: Svartberg
authors.affiliation: a Department of Clinical Medicine , Tromsø Endocrine Research Group, UiT The Arctic University of Norway , Tromsø , Norway ;|b Division of Internal Medicine , University Hospital of North Norway , Tromsø , Norway ;
authors.forename: Ragnar M
authors.initials: RM
authors.lastname: Joakimsen
authors.affiliation: a Department of Clinical Medicine , Tromsø Endocrine Research Group, UiT The Arctic University of Norway , Tromsø , Norway ;|b Division of Internal Medicine , University Hospital of North Norway , Tromsø , Norway ;
authors.forename: Guri
authors.initials: G
authors.lastname: Grimnes
authors.affiliation: c Division of Head and Motion, Department of Rheumatology , Nordland Hospital , Bodø , Norway.
authors.forename: Moira Y S
authors.initials: MY
authors.lastname: Hutchinson
mesh_terms: D000328:Adult; D000368:Aged; D018890:Chemoprevention / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010919:Placebos / Q000008:administration & dosage; D012141:Respiratory Tract Infections / Q000517:prevention & control; D016896:Treatment Outcome; D014552:Urinary Tract Infections / Q000517:prevention & control*; D014807:Vitamin D / Q000008:administration & dosage*
chemical_list: D010919:Placebos; D014807:Vitamin D
keywords: Diabetes; respiratory infection; urinary tract infection; vitamin D