title: Over-the-counter analgesics and risk of ovarian cancer.
abstract: BACKGROUND
  Evidence that aspirin and other non-steroidal anti-inflammatory drugs reduce risk for colorectal cancer has prompted interest in their ability to prevent other cancers. We aimed to find out what effect over-the-counter analgesics have on risk of ovarian cancer.
  
  
  METHODS
  In a case-control study we compared use of over-the-counter analgesics by 563 women from eastern Massachusetts and New Hampshire, USA, who had epithelial ovarian cancer with 523 women from the general population. We calculated exposure odds ratios to estimate the effect of over-the-counter analgesics on ovarian cancer risk. Use of over-the-counter analgesics was assessed through interviews and defined as use at least once a week continuously for at least 6 months.
  
  
  RESULTS
  The odds ratio for risk of ovarian cancer for aspirin use was 0.75 (95% CI 0.52-1.10), that for ibuprofen was 1.03 (0.64-1.64), and that for paracetamol was 0.52 (0.31-0.86), after adjusting for age, study centre, education, religion, parity, oral contraceptive use, and menstrual, arthritic, or headache pain. Relative to no use, the lower risk of ovarian cancer associated with paracetamol was more apparent for use on a daily basis, 0.39 (0.21-0.74), for more than 10 years of use, 0.40 (0.19-0.88), or for more than 20 tablet years defined as (tablets per day x years of use), 0.45 (0.20-0.99).
  
  
  CONCLUSIONS
  In our data, there was a statistically significant inverse association between paracetamol use and ovarian cancer risk. There was a modest but non-significant inverse association with aspirin use and ovarian cancer and no association with ibuprofen use. Experimental studies in rodents demonstrating uterine and ovarian atrophy at high doses of paracetamol and decreased ovarian-cyst formation at lower doses suggest a biological basis for our observations.
authors.affiliation: Department of Obstetrics and Gynecology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: D W
authors.initials: DW
authors.lastname: Cramer
authors.forename: B L
authors.initials: BL
authors.lastname: Harlow
authors.forename: L
authors.initials: L
authors.lastname: Titus-Ernstoff
authors.forename: K
authors.initials: K
authors.lastname: Bohlke
authors.forename: W R
authors.initials: WR
authors.lastname: Welch
authors.forename: E R
authors.initials: ER
authors.lastname: Greenberg
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage / Q000009:adverse effects; D000328:Adult; D000368:Aged; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000009:adverse effects*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000009:adverse effects*; D001241:Aspirin / Q000008:administration & dosage / Q000009:adverse effects; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007052:Ibuprofen / Q000008:administration & dosage / Q000009:adverse effects; D008404:Massachusetts / Q000453:epidemiology; D008875:Middle Aged; D009513:New Hampshire / Q000453:epidemiology; D004366:Nonprescription Drugs / Q000008:administration & dosage / Q000009:adverse effects*; D010051:Ovarian Neoplasms / Q000139:chemically induced* / Q000453:epidemiology; D012307:Risk Factors; D013997:Time Factors
chemical_list: D018712:Analgesics, Non-Narcotic; D000894:Anti-Inflammatory Agents, Non-Steroidal; D004366:Nonprescription Drugs; D000082:Acetaminophen; D001241:Aspirin; D007052:Ibuprofen