title: Prescriptions for selective cyclooxygenase-2 inhibitors, non-selective non-steroidal anti-inflammatory drugs, and risk of breast cancer in a population-based case-control study.
abstract: BACKGROUND
  Non-steroidal anti-inflammatory drugs (NSAIDs) prevent the growth of mammary tumours in animal models. Two population-based case-control studies suggest a reduced risk of breast cancer associated with selective cyclooxygenase-2 (sCox-2) inhibitor use, but data regarding the association between breast cancer occurrence and use of non-selective NSAIDs are conflicting.
  
  
  METHODS
  We conducted a population-based case-control study using Danish healthcare databases to examine if use of NSAIDs, including sCox-2 inhibitors, was associated with a reduced risk of breast cancer. We included 8,195 incident breast cancer cases diagnosed in 1991 through 2006 and 81,950 population controls.
  
  
  RESULTS
  Overall, we found no reduced breast cancer risk in ever users (>2 prescriptions) of sCox-2 inhibitors (odds ratio (OR) = 1.08, 95% confidence interval (95% CI) = 0.99, 1.18), aspirin (OR = 0.98, 95% CI = 0.90-1.07), or non-selective NSAIDs OR = 1.04, (95% CI = 0.98, 1.10)). Recent use (>2 prescriptions within two years of index date) of sCox-2 inhibitors, aspirin, or non-selective NSAIDs was likewise not associated with breast cancer risk (Ors = 1.06 (95% CI = 0.96, 1.18), 0.96 (95% CI = 0.87, 1.06) and 0.99 (95% CI = 0.85, 1.16), respectively). Risk estimates by duration (<10, 10 to 15, 15+ years) or intensity (low/medium/high) of NSAID use were also close to unity. Regardless of intensity, shorter or long-term NSAID use was not significantly associated with breast cancer risk.
  
  
  CONCLUSIONS
  Overall, we found no compelling evidence of a reduced risk of breast cancer associated with use of sCox-2 inhibitors, aspirin, or non-selective NSAIDs.
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Olof Palmes Alle 43-45, Aarhus N, Denmark. dc@dce.au.dk
authors.forename: Deirdre P
authors.initials: DP
authors.lastname: Cronin-Fenton
authors.forename: Lars
authors.initials: L
authors.lastname: Pedersen
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Lash
authors.forename: Søren
authors.initials: S
authors.lastname: Friis
authors.forename: John A
authors.initials: JA
authors.lastname: Baron
authors.forename: Henrik T
authors.initials: HT
authors.lastname: Sørensen
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000453:epidemiology*; D016022:Case-Control Studies; D052246:Cyclooxygenase 2 Inhibitors / Q000627:therapeutic use*; D016208:Databases, Factual / Q000706:statistics & numerical data; D003718:Denmark / Q000453:epidemiology; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D004363:Drug Utilization / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D012307:Risk Factors; D013997:Time Factors
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D052246:Cyclooxygenase 2 Inhibitors