title: Association of diabetes mellitus with prostate cancer: nested case-control study (Prostate testing for cancer and treatment study).
abstract: Observational studies suggest that diabetes is associated with a decreased risk of prostate cancer, but few are population based or have investigated associations with cancer stage or duration of diabetes. We report a case-control study nested within the population-based Prostate testing for cancer and Treatment (ProtecT) study ISRCTN20141297. Men aged 50-69 years based around 9 UK cities were invited for a prostate-specific antigen (PSA) test between June 2002 and November 2006. Amongst 55,215 PSA-tested men, 1,966 had histologically confirmed prostate cancer; of these, 1,422 (72.3%) completed the questionnaire and 1,291 (65.7%) had complete data for analysis. We randomly selected 6,479 age- (within 5 years) and general practice-matched controls. The prevalence of diabetes was 89/1,291 (6.9%) in cases and 555/6,479 (8.6%) in controls. Diabetes was associated with a reduced risk of prostate cancer (odds ratio = 0.78; 95% confidence interval: 0.61-0.99). There was weak evidence that the inverse association was greater for well- versus poorly differentiated cancers (p = 0.07). The magnitude of the inverse association did not change with increasing duration of diabetes (p for trend = 0.95). Diabetes is associated with a decreased risk of PSA-detected prostate cancer. These data add to the evidence of the association of diabetes with prostate cancer in the PSA era.
authors.affiliation: Department of Social Medicine, University of Bristol, Bristol, UK.
authors.forename: Emma L
authors.initials: EL
authors.lastname: Turner
authors.forename: Janet Athene
authors.initials: JA
authors.lastname: Lane
authors.forename: Jenny L
authors.initials: JL
authors.lastname: Donovan
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Davis
authors.forename: Chris
authors.initials: C
authors.lastname: Metcalfe
authors.forename: David E
authors.initials: DE
authors.lastname: Neal
authors.forename: Freddie C
authors.initials: FC
authors.lastname: Hamdy
authors.forename: Richard M
authors.initials: RM
authors.lastname: Martin
mesh_terms: D000368:Aged; D015992:Body Mass Index; D016022:Case-Control Studies; D003920:Diabetes Mellitus / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000517:prevention & control*; D013997:Time Factors
chemical_list: D017430:Prostate-Specific Antigen