title: Low-dose aspirin use and the risk of ovarian cancer in Denmark.
abstract: BACKGROUND
  A comprehensive body of evidence has shown that aspirin has cancer-preventive effects, particularly against gastrointestinal cancer, but its effects on the risk of ovarian cancer are less well established. This nationwide case-control study examined the association between low-dose aspirin and the risk of ovarian cancer.
  
  
  METHODS
  We identified all patients in the Danish Cancer Registry aged 30-84 years old with a histologically verified first diagnosis of epithelial ovarian cancer during 2000-2011. Each patient was sex- and age-matched to 15 population controls using risk-set sampling. Prescription use, comorbidity, reproductive history, and demographic characteristics data were obtained from nationwide registries. The use of low-dose (75-150 mg) aspirin was defined according to the dose as well as the duration and consistency of use. Conditional logistic regression was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs) for the association between low-dose aspirin use and the risk of epithelial ovarian cancer, both overall and for specific histological types.
  
  
  RESULTS
  For 4103 ovarian cancer cases and 58 706 population controls, the adjusted OR for epithelial ovarian cancer associated with ever use (≥2 prescriptions) of low-dose aspirin was 0.94 (95% CI 0.85-1.05). ORs for epithelial ovarian cancer were lower with the use of 150 mg aspirin tablets (OR = 0.82; 95% CI 0.68-0.99) and with long-term use (≥5 years) of low-dose aspirin (OR = 0.77; 95% CI 0.55-1.08). Continuous long-term use of low-dose aspirin, defined as close consecutive prescriptions, was associated with a further reduction in OR (0.56; 95% CI 0.32-0.97). For histological types of epithelial ovarian cancer, the strongest inverse associations with low-dose aspirin use were seen for mucinous and endometrioid tumours.
  
  
  CONCLUSIONS
  This nationwide case-control study indicates that low-dose aspirin use may be associated with a reduced risk of epithelial ovarian cancer.
authors.affiliation: Danish Cancer Society Research Centre, Danish Cancer Society, Copenhagen. Electronic address: baandrup@cancer.dk.
authors.forename: L
authors.initials: L
authors.lastname: Baandrup
authors.affiliation: Danish Cancer Society Research Centre, Danish Cancer Society, Copenhagen; The Gynaecologic Clinic, Juliane Marie Centre, Rigshospitalet, University of Copenhagen, Copenhagen.
authors.forename: S K
authors.initials: SK
authors.lastname: Kjaer
authors.affiliation: Danish Cancer Society Research Centre, Danish Cancer Society, Copenhagen.
authors.forename: J H
authors.initials: JH
authors.lastname: Olsen
authors.affiliation: Danish Cancer Society Research Centre, Danish Cancer Society, Copenhagen.
authors.forename: C
authors.initials: C
authors.lastname: Dehlendorff
authors.affiliation: Danish Cancer Society Research Centre, Danish Cancer Society, Copenhagen; Department of Public Health, University of Copenhagen, Copenhagen; Institute of Clinical Medicine, Department of Clinical Epidemiology, Aarhus University, Aarhus, Denmark.
authors.forename: S
authors.initials: S
authors.lastname: Friis
mesh_terms: D018262:Adenocarcinoma, Clear Cell / Q000188:drug therapy / Q000453:epidemiology* / Q000473:pathology; D002288:Adenocarcinoma, Mucinous / Q000188:drug therapy / Q000453:epidemiology* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D001241:Aspirin / Q000627:therapeutic use*; D016022:Case-Control Studies; D018284:Cystadenocarcinoma, Serous / Q000188:drug therapy / Q000453:epidemiology* / Q000473:pathology; D003718:Denmark / Q000453:epidemiology; D004305:Dose-Response Relationship, Drug; D016889:Endometrial Neoplasms / Q000188:drug therapy / Q000453:epidemiology* / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010051:Ovarian Neoplasms / Q000188:drug therapy / Q000453:epidemiology* / Q000473:pathology; D011379:Prognosis; D012042:Registries; D012307:Risk Factors
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D001241:Aspirin
keywords: aspirin; chemoprevention; ovarian cancer