title: Cimetidine and other histamine2-receptor antagonist use in relation to risk of breast cancer.
abstract: OBJECTIVE
  Cimetidine, a histamine2-receptor antagonist (H2 blocker) commonly used to treat symptoms of peptic and duodenal ulcer, influences both hormonal and immune pathways. We investigated the influence of cimetidine use on the risk of breast cancer in our hospital-based case control surveillance study.
  
  
  METHODS
  Data on medication use and other factors were elicited from patients admitted to hospitals from 1977 to 2002. We compared 6,994 breast cancer cases with a control group comprising cancer (n = 2,478) and noncancer (n = 6,004) diagnoses. Conditional logistic regression models were used to estimate odds ratios for H2 blocker use that began at least 1 year prior to admission. Regular use was defined as use for at least 4 days per week for at least 3 continuous months.
  
  
  RESULTS
  The odds ratio for breast cancer among regular users of cimetidine was 0.9 (95% confidence interval, 0.6-1.2) using a combined cancer and noncancer control group. For use of 4 or more years' duration, the odds ratio was < 1.0 but was not statistically significant. The odds ratio for the regular use of other H2 blockers was 0.9 (95% confidence interval, 0.6-1.3).
  
  
  CONCLUSIONS
  Our data agree with data from three prior studies which indicate that cimetidine is not associated with the risk of breast cancer. Other H2 blockers were also unrelated to the risk of breast cancer.
authors.affiliation: Slone Epidemiology Center, Boston University, 1371 Beacon Street, Boston, MA 02446, USA. pcoogan@slone.bu.edu
authors.forename: Patricia F
authors.initials: PF
authors.lastname: Coogan
authors.forename: Yuqing
authors.initials: Y
authors.lastname: Zhang
authors.forename: Julie R
authors.initials: JR
authors.lastname: Palmer
authors.forename: Brian L
authors.initials: BL
authors.lastname: Strom
authors.forename: Lynn
authors.initials: L
authors.lastname: Rosenberg
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000139:chemically induced*; D016022:Case-Control Studies; D002927:Cimetidine / Q000009:adverse effects*; D005260:Female; D006635:Histamine H2 Antagonists / Q000009:adverse effects*; D006760:Hospitalization; D006801:Humans; D016015:Logistic Models; D008499:Medical Records; D008875:Middle Aged
chemical_list: D006635:Histamine H2 Antagonists; D002927:Cimetidine