title: Risk factors for breast cancer in women biopsied for benign breast disease: a nested case-control study.
abstract: OBJECTIVE
  Women with a history of benign breast disease are at increased risk of subsequent breast cancer. However, few studies have examined whether established breast cancer risk factors other than histology are associated with an altered risk of breast cancer in women with benign breast disease. We used a nested case-control design within a large, multi-center cohort of women biopsied for benign breast disease (BBD) to estimate odds ratios for breast cancer in association with exposure to a range of personal and lifestyle factors.
  
  
  METHODS
  Cases were women biopsied for BBD who subsequently developed breast cancer; controls were individually matched to cases on center and age at diagnosis and were women biopsied for BBD who did not develop breast cancer in the same follow-up interval as that for the cases. After excluding women with prevalent breast cancer, 1357 records (661 case records and 696 records) were available for analysis. We used conditional logistic regression to obtain crude and multivariable-adjusted estimates of the association between specific factors and risk of breast cancer.
  
  
  RESULTS
  In multivariable analyses age at first live birth, number of pregnancies, and postmenopausal status were inversely associated with risk of breast cancer. The odds ratio for women with age at first birth <25 years and >or=3 pregnancies, relative to nulliparous women, was 0.49, 95% confidence interval 0.13-0.79, and that for postmenopausal women relative to premenopausal women was 0.60, 95% CI 0.37-0.99.
  
  
  CONCLUSIONS
  Further study of personal factors influencing the risk of breast cancer in women with BBD may help to identify subgroups of the population at increased risk of invasive disease.
authors.affiliation: Department of Epidemiology and Population Health, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA. Geoffrey.kabat@einstein.yu.edu <Geoffrey.kabat@einstein.yu.edu>
authors.forename: Geoffrey C
authors.initials: GC
authors.lastname: Kabat
authors.forename: Joan G
authors.initials: JG
authors.lastname: Jones
authors.forename: Neal
authors.initials: N
authors.lastname: Olson
authors.forename: Abdissa
authors.initials: A
authors.lastname: Negassa
authors.forename: Catherine
authors.initials: C
authors.lastname: Duggan
authors.forename: Mindy
authors.initials: M
authors.lastname: Ginsberg
authors.forename: Rita A
authors.initials: RA
authors.lastname: Kandel
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Glass
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Rohan
mesh_terms: D000328:Adult; D000367:Age Factors; D001706:Biopsy; D001941:Breast Diseases / Q000473:pathology*; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008572:Menarche; D008593:Menopause; D008875:Middle Aged; D010298:Parity; D011247:Pregnancy; D012307:Risk Factors