title: Periodontal Disease and Breast Cancer: Prospective Cohort Study of Postmenopausal Women.
abstract: BACKGROUND
  Periodontal disease has been consistently associated with chronic disease; there are no large studies of breast cancer, although oral-associated microbes are present in breast tumors.
  
  
  METHODS
  In the Women's Health Initiative Observational Study, a prospective cohort of postmenopausal women, 73,737 women without previous breast cancer were followed. Incident, primary, invasive breast tumors were verified by physician adjudication. Periodontal disease was by self-report. HRs and 95% confidence intervals (CI) were estimated by Cox proportional hazards, adjusted for breast cancer risk factors. Because the oral microbiome of those with periodontal disease differs with smoking status, we examined associations stratified by smoking.
  
  
  RESULTS
  2,124 incident, invasive breast cancer cases were identified after mean follow-up of 6.7 years. Periodontal disease, reported by 26.1% of women, was associated with increased breast cancer risk (HR 1.14; 95% CI, 1.03-1.26), particularly among former smokers who quit within 20 years (HR 1.36; 95% CI, 1.05-1.77). Among current smokers, the trend was similar (HR 1.32; 95% CI, 0.83-2.11); there were few cases (n = 74) and the CI included the null. The population attributable fraction was 12.06% (95% CI, 1.12-21.79) and 10.90% (95% CI, 10.31-28.94) for periodontal disease among former smokers quitting within 20 years and current smokers, respectively.
  
  
  CONCLUSIONS
  Periodontal disease, a common chronic inflammatory disorder, was associated with increased risk of postmenopausal breast cancer, particularly among former smokers who quit in the past 20 years.
  
  
  CONCLUSIONS
  Understanding a possible role of the oral microbiome in breast carcinogenesis could impact prevention.
authors.affiliation: Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, New York. jfreuden@buffalo.edu.
authors.forename: Jo L
authors.initials: JL
authors.lastname: Freudenheim
authors.affiliation: Department of Oral Biology, School of Dental Medicine, University at Buffalo, State University of New York, Buffalo, New York.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Genco
authors.affiliation: Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, New York.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: LaMonte
authors.affiliation: Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, New York.
authors.forename: Amy E
authors.initials: AE
authors.lastname: Millen
authors.affiliation: Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, New York.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Hovey
authors.affiliation: Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, New York.
authors.forename: Xiaodan
authors.initials: X
authors.lastname: Mai
authors.affiliation: Department of Diagnostic and Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston School of Dentistry, Houston, Texas.
authors.forename: Ngozi
authors.initials: N
authors.lastname: Nwizu
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Andrews
authors.affiliation: Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, New York.
authors.forename: Jean
authors.initials: J
authors.lastname: Wactawski-Wende
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D010510:Periodontal Diseases / Q000150:complications*; D017698:Postmenopause; D011379:Prognosis; D011446:Prospective Studies; D016387:Women's Health