title: Consistent lack of association between breast cancer and oral contraceptives using either hospital or neighborhood controls.
abstract: BACKGROUND
  Case-control studies of oral contraceptive use and breast cancer have used neighborhood, population, or hospital controls.
  
  
  METHODS
  To determine whether this association differs according to type of controls, interview data from 131 incident cases of breast cancer were compared with those of 189 hospital controls and 182 neighborhood controls Study subjects were white females recruited between 1973 and 1975 from among residents of Baltimore City and County ages 18 to 59 years.
  
  
  RESULTS
  Adjusted relative odds of breast cancer related to ever versus never use of oral contraceptives were 1.0 and 0.8, using hospital and neighborhood controls, respectively. Relative odds did not increase proportionally to duration of oral contraceptive use or to progestogen potency. Although few subjects had used oral contraceptives for more than 2 years, almost all pill brands contained more than 49 micrograms of ethinyl estradiol or of mestranol.
  
  
  CONCLUSIONS
  Results from the present study do not support the hypothesis that early preparations of oral contraceptives increased breast cancer risk among white women, regardless of whether controls are neighbors of the cases or hospital patients. However, its conclusions cannot be generalized to women who began taking the pill before their first full-term birth or took it for more than 2 years.
authors: Department of Epidemiology, Johns Hopkins School of Public Health, Baltimore, Maryland 21205.
authors: A
authors: A
authors: Morabia
authors: M
authors: M
authors: Szklo
authors: W
authors: W
authors: Stewart
authors: L
authors: L
authors: Schuman
authors: D B
authors: DB
authors: Thomas
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001943:Breast Neoplasms / Q000139:chemically induced* / Q000453:epidemiology*; D016022:Case-Control Studies; D003276:Contraceptives, Oral / Q000009:adverse effects*; D004305:Dose-Response Relationship, Drug; D004522:Educational Status; D004997:Ethinyl Estradiol / Q000009:adverse effects; D005260:Female; D006801:Humans; D008396:Maryland / Q000453:epidemiology; D016555:Matched-Pair Analysis; D008656:Mestranol / Q000009:adverse effects; D008875:Middle Aged; D016017:Odds Ratio; D012107:Research Design; D013997:Time Factors
chemical_list: D003276:Contraceptives, Oral; D004997:Ethinyl Estradiol; D008656:Mestranol