title: BRCA1 and BRCA2 mutation carriers, oral contraceptive use, and breast cancer before age 50.
abstract: BACKGROUND
  Understanding the effect of oral contraceptives on risk of breast cancer in BRCA1 or BRCA2 mutation carriers is important because oral contraceptive use is a common, modifiable practice.
  
  
  METHODS
  We studied 497 BRCA1 and 307 BRCA2 mutation carriers, of whom 195 and 128, respectively, had been diagnosed with breast cancer. Case-control analyses were conducted using unconditional logistic regression with adjustments for family history and familial relationships and were restricted to subjects with a reference age under 50 years.
  
  
  RESULTS
  For BRCA1 mutation carriers, there was no significant association between risk of breast cancer and use of oral contraceptives for at least 1 year [odds ratio (OR), 0.77; 95% confidence interval (95% CI), 0.53-1.12] or duration of oral contraceptive use (P(trend) = 0.62). For BRCA2 mutation carriers, there was no association with use of oral contraceptives for at least 1 year (OR, 1.62; 95% CI, 0.90-2.92); however, there was an association of elevated risk with oral contraceptive use for at least 5 years (OR, 2.06; 95% CI, 1.08-3.94) and with duration of use (OR(trend) per year of use, 1.08; P = 0.008). Similar results were obtained when we considered only use of oral contraceptives that first started in 1975 or later.
  
  
  CONCLUSIONS
  We found no evidence overall that use of oral contraceptives for at least 1 year is associated with breast cancer risk for BRCA1 and BRCA2 mutation carriers before age 50. For BRCA2 mutation carriers, use of oral contraceptives may be associated with an increased risk of breast cancer among women who use them for at least 5 years. Further studies reporting results separately for BRCA1 and BRCA2 mutation carriers are needed to resolve this important issue.
authors.affiliation: Department of Preventive Medicine, University of Southern California-Keck School of Medicine, 1441 Eastlake Avenue, MS 9175, Los Angeles, CA 90089-9175, USA. haile@usc.edu
authors.forename: Robert W
authors.initials: RW
authors.lastname: Haile
authors.forename: Duncan C
authors.initials: DC
authors.lastname: Thomas
authors.forename: Valerie
authors.initials: V
authors.lastname: McGuire
authors.forename: Anna
authors.initials: A
authors.lastname: Felberg
authors.forename: Esther M
authors.initials: EM
authors.lastname: John
authors.forename: Roger L
authors.initials: RL
authors.lastname: Milne
authors.forename: John L
authors.initials: JL
authors.lastname: Hopper
authors.forename: Mark A
authors.initials: MA
authors.lastname: Jenkins
authors.forename: A Joan
authors.initials: AJ
authors.lastname: Levine
authors.forename: Mary M
authors.initials: MM
authors.lastname: Daly
authors.forename: Saundra S
authors.initials: SS
authors.lastname: Buys
authors.forename: Ruby T
authors.initials: RT
authors.lastname: Senie
authors.forename: Irene L
authors.initials: IL
authors.lastname: Andrulis
authors.forename: Julia A
authors.initials: JA
authors.lastname: Knight
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Godwin
authors.forename: Melissa
authors.initials: M
authors.lastname: Southey
authors.forename: Margaret R E
authors.initials: MR
authors.lastname: McCredie
authors.forename: Graham G
authors.initials: GG
authors.lastname: Giles
authors.forename: Lesley
authors.initials: L
authors.lastname: Andrews
authors.forename: Katherine
authors.initials: K
authors.lastname: Tucker
authors.forename: Alexander
authors.initials: A
authors.lastname: Miron
authors.forename: Carmel
authors.initials: C
authors.lastname: Apicella
authors.forename: Andrea
authors.initials: A
authors.lastname: Tesoriero
authors.forename: Anita
authors.initials: A
authors.lastname: Bane
authors.forename: Malcolm C
authors.initials: MC
authors.lastname: Pike
authors.forename: Alice S
authors.initials: AS
authors.lastname: Whittemore
mesh_terms: D000328:Adult; D001315:Australia / Q000453:epidemiology; D001943:Breast Neoplasms / Q000453:epidemiology / Q000235:genetics*; D002170:Canada / Q000453:epidemiology; D002278:Carcinoma in Situ / Q000453:epidemiology / Q000235:genetics*; D018270:Carcinoma, Ductal, Breast / Q000453:epidemiology / Q000235:genetics*; D016022:Case-Control Studies; D003276:Contraceptives, Oral / Q000494:pharmacology*; D005260:Female; D019398:Genes, BRCA1 / Q000187:drug effects*; D024522:Genes, BRCA2 / Q000187:drug effects*; D020022:Genetic Predisposition to Disease; D006579:Heterozygote; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D009154:Mutation / Q000187:drug effects*; D011960:Receptors, Estrogen / Q000187:drug effects; D011980:Receptors, Progesterone / Q000187:drug effects; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013997:Time Factors; D014481:United States / Q000453:epidemiology
chemical_list: D003276:Contraceptives, Oral; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone