title: Vasectomy and risk of prostate cancer.
abstract: BACKGROUND
  Vasectomy is a common method of contraception, but concern exists about a reported association with risk of prostate cancer.
  
  
  OBJECTIVE
  To examine whether vasectomy increases risk of prostate cancer.
  
  
  METHODS
  National population-based case-control study of 923 new cases of prostate cancer among men aged 40 to 74 years from the New Zealand Cancer Registry who were on the general electoral roll. Controls (n = 1224) were randomly selected from the general electoral roll, with frequency matching to cases in 5-year age groups. Cases (3-15 months after diagnosis) and controls were interviewed by telephone between January 1997 and November 1999.
  
  
  METHODS
  Relative risk (RR) of prostate cancer for men who had had a vasectomy vs those who had not.
  
  
  RESULTS
  There was no association between prostate cancer and vasectomy (RR, 0.92; 95% confidence interval [CI], 0.75-1.14) nor with time since vasectomy (RR, 0.92; 95% CI, 0.68-1.23 for > or = 25 years since vasectomy). Adjustment for social class, geographic region, religious affiliation, and a family history of prostate cancer did not affect these RRs.
  
  
  CONCLUSIONS
  Vasectomy does not increase the risk of prostate cancer, even after 25 years or more.
authors.affiliation: Hugh Adam Cancer Epidemiology Unit, Department of Preventive and Social Medicine, University of Otago Medical School, PO Box 913, Dunedin, New Zealand. brian.cox@stonebow.otago.ac.nz
authors.forename: Brian
authors.initials: B
authors.lastname: Cox
authors.forename: Mary J
authors.initials: MJ
authors.lastname: Sneyd
authors.forename: Charlotte
authors.initials: C
authors.lastname: Paul
authors.forename: Brett
authors.initials: B
authors.lastname: Delahunt
authors.forename: David C G
authors.initials: DC
authors.lastname: Skegg
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D011471:Prostatic Neoplasms / Q000453:epidemiology* / Q000209:etiology; D012042:Registries; D012306:Risk; D014659:Vasectomy / Q000009:adverse effects / Q000706:statistics & numerical data*