title: Use of 5α-reductase inhibitors for lower urinary tract symptoms and risk of prostate cancer in Swedish men: nationwide, population based case-control study.
abstract: OBJECTIVE
  To assess the association between 5α-reductase inhibitor (5-ARI) use in men with lower urinary tract symptoms and prostate cancer risk.
  
  
  METHODS
  Nationwide, population based case-control study for men diagnosed with prostate cancer in 2007-09 within the Prostate Cancer data Base Sweden 2.0.
  
  
  METHODS
  The National Prostate Cancer Register, National Patient Register, census, and Prescribed Drug Register in Sweden, from which we obtained data on 5-ARI use before date of prostate cancer diagnosis.
  
  
  METHODS
  26,735 cases and 133,671 matched controls; five controls per case were randomly selected from matched men in the background population. 7815 men (1499 cases and 6316 controls) had been exposed to 5-ARI. 412 men had been exposed to 5-ARI before the diagnosis of a cancer with Gleason score 8-10.
  
  
  METHODS
  Risk of prostate cancer calculated as odds ratios and 95% confidence intervals by conditional logistic regression analyses.
  
  
  RESULTS
  Risk of prostate cancer overall decreased with an increasing duration of exposure; men on 5-ARI treatment for more than three years had an odds ratio of 0.72 (95% confidence interval 0.59 to 0.89; P<0.001 for trend). The same pattern was seen for cancers with Gleason scores 2-6 and score 7 (both P<0.001 for trend). By contrast, the risk of tumours with Gleason scores 8-10 did not decrease with increasing exposure time to 5-ARI (for 0-1 year of exposure, odds ratio 0.96 (95% confidence interval 0.83 to 1.11); for 1-2 years, 1.07 (0.88 to 1.31); for 2-3 years, 0.96 (0.72 to 1.27); for >3 years, 1.23 (0.90 to 1.68); P=0.46 for trend).
  
  
  CONCLUSIONS
  Men treated with 5-ARI for lower urinary tract symptoms had a decreased risk of cancer with Gleason scores 2-7, and showed no evidence of an increased risk of cancer with Gleason scores 8-10 after up to four years' treatment.
authors.affiliation: Department of Surgery and Perioperative Sciences, Umeå University, 901 85 Umeå, Sweden. drobinson@telia.com
authors.forename: David
authors.initials: D
authors.lastname: Robinson
authors.forename: Hans
authors.initials: H
authors.lastname: Garmo
authors.forename: Anna
authors.initials: A
authors.lastname: Bill-Axelson
authors.forename: Lorelei
authors.initials: L
authors.lastname: Mucci
authors.forename: Lars
authors.initials: L
authors.lastname: Holmberg
authors.forename: Pär
authors.initials: P
authors.lastname: Stattin
mesh_terms: D058891:5-alpha Reductase Inhibitors / Q000627:therapeutic use*; D016022:Case-Control Studies; D006801:Humans; D059411:Lower Urinary Tract Symptoms / Q000188:drug therapy*; D008297:Male; D011471:Prostatic Neoplasms / Q000453:epidemiology* / Q000517:prevention & control; D018570:Risk Assessment; D013548:Sweden
chemical_list: D058891:5-alpha Reductase Inhibitors