title: Migraine in postmenopausal women and the risk of invasive breast cancer.
abstract: BACKGROUND
  The frequency of migraine headache changes at various times of a woman's reproductive cycle. Menarche, menses, pregnancy, and perimenopause may carry a different migraine risk conceivably because of fluctuating estrogen levels, and in general, migraine frequency is associated with falling estrogen levels. Given the strong relationship between endogenous estrogen levels and breast cancer risk, migraine sufferers may experience a reduced risk of breast cancer.
  
  
  METHODS
  We combined data from two population-based case-control studies to examine the relationship between migraine and risk of postmenopausal invasive breast cancer among 1,199 ductal carcinoma cases, 739 lobular carcinoma cases, and 1,474 controls 55 to 79 years of age. Polytomous logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI).
  
  
  RESULTS
  Women who reported a clinical diagnosis of migraine had reduced risks of ductal carcinoma (OR, 0.67; 95% CI, 0.54-0.82) and lobular carcinoma (OR, 0.68; 95% CI, 0.52-0.90). These associations were primarily limited to hormone receptor-positive tumors as migraine was associated with a 0.65-fold (95% CI, 0.51-0.83) reduced risk of estrogen receptor-positive (ER+)/progesterone receptor-positive (PR+) ductal carcinoma. The reductions in risk observed were seen among migraine sufferers who did and did not use prescription medications for their migraines.
  
  
  CONCLUSIONS
  These data suggest that a history of migraine is associated with a decreased risk of breast cancer, particularly among ER+/PR+ ductal and lobular carcinomas. Because this is the first study to address an association between migraine history and breast cancer risk, additional studies are needed to confirm this finding.
authors.affiliation: Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, M4-C308, P. O. Box 19024, Seattle, WA 98109-1024, USA. rmathes@u.washington.edu
authors.forename: Robert W
authors.initials: RW
authors.lastname: Mathes
authors.forename: Kathleen E
authors.initials: KE
authors.lastname: Malone
authors.forename: Janet R
authors.initials: JR
authors.lastname: Daling
authors.forename: Scott
authors.initials: S
authors.lastname: Davis
authors.forename: Sylvia M
authors.initials: SM
authors.lastname: Lucas
authors.forename: Peggy L
authors.initials: PL
authors.lastname: Porter
authors.forename: Christopher I
authors.initials: CI
authors.lastname: Li
mesh_terms: D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000453:epidemiology*; D018270:Carcinoma, Ductal, Breast / Q000453:epidemiology*; D018275:Carcinoma, Lobular / Q000453:epidemiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D008881:Migraine Disorders / Q000188:drug therapy / Q000453:epidemiology*; D009361:Neoplasm Invasiveness; D017698:Postmenopause; D018570:Risk Assessment
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal