title: Association of selected medical conditions with breast cancer risk in Korea.
abstract: OBJECTIVE
  To estimate the effect of medical conditions in the population of Korea on breast cancer risk in a case-control study.
  
  
  METHODS
  The cases were 3242 women with incident, histologically confirmed breast cancer in two major hospitals interviewed between 2001 and 2007. The controls were 1818 women each admitted to either of those two hospitals for a variety of non-neoplastic conditions. Information on each disease was obtained from a standardized questionnaire by trained personnel. Odds ratios (ORs) for each disease were derived from multiple logistic regression adjusted for age, age of menarche, pregnancy, age of first pregnancy, and family history of breast cancer.
  
  
  RESULTS
  Among all of the incident breast cancer patients, pre-existing diabetes (OR, 1.33; 95% confidence interval [CI], 0.99 to 1.78), hypertension (OR, 1.46; 95% CI, 1.18 to 1.83), thyroid diseases (OR, 1.26; 95% CI, 1.00 to 1.58), and ovarian diseases (OR, 1.70; 95% CI, 1.23 to 2.35) were associated with an increased risk of breast cancer when other factors were adjusted for. In a stratified analysis by menopausal status, pre-existing hypertension (pre-menopause OR, 0.80; 95% CI, 0.48 to 1.34 vs. post-menopause OR, 1.87; 95% CI, 1.44 to 2.43; p-heterogeneity <0.01) and ovarian disease (pre-menopause OR, 4.20; 95% CI, 1.91 to 9.24 vs. post-menopause OR, 1.39; 95% CI, 1.02 to 1.91; p-heterogeneity 0.01) showed significantly different risks of breast cancer.
  
  
  CONCLUSIONS
  Our results suggest the possibility that medical conditions such as hypertension affect breast cancer development, and that this can differ by menopausal status. Our study also indicates a possible correlation between ovarian diseases and breast cancer risk.
authors.affiliation: Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea. ; Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Sun Jae
authors.initials: SJ
authors.lastname: Jung
authors.affiliation: Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea. ; Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, Korea.
authors.forename: Minkyo
authors.initials: M
authors.lastname: Song
authors.affiliation: Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea. ; Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, Korea.
authors.forename: Ji-Yeob
authors.initials: JY
authors.lastname: Choi
authors.affiliation: Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Nan
authors.initials: N
authors.lastname: Song
authors.affiliation: Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea. ; Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea. ; Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, Korea.
authors.forename: Sue Kyung
authors.initials: SK
authors.lastname: Park
authors.affiliation: Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Keun-Young
authors.initials: KY
authors.lastname: Yoo
authors.affiliation: Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea. ; Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea. ; Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, Korea.
authors.forename: Daehee
authors.initials: D
authors.lastname: Kang
mesh_terms: D000367:Age Factors; D001943:Breast Neoplasms / Q000150:complications / Q000453:epidemiology*; D016022:Case-Control Studies; D048909:Diabetes Complications; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications; D007407:Interviews as Topic; D008572:Menarche; D008875:Middle Aged; D016017:Odds Ratio; D010049:Ovarian Diseases / Q000150:complications; D017698:Postmenopause; D011247:Pregnancy; D017697:Premenopause; D056910:Republic of Korea; D012307:Risk Factors
keywords: Breast neoplasms; Diabetes mellitus; Hypertension; Menopause; Ovarian diseases