title: Breast Cancer Research in the Nurses' Health Studies: Exposures Across the Life Course.
abstract: OBJECTIVE
  To review the contribution of the Nurses' Heath Study (NHS) and the NHS II in identifying risk and protective factors for breast cancer incidence and survival.
  
  
  METHODS
  We conducted a narrative review of NHS and NHS II articles on breast cancer incidence and survival published from 1976 to 2016, with a focus on exogenous and endogenous hormones; lifestyle factors, including diet, physical activity, and aspirin use; intermediate markers of risk; and genetic factors.
  
  
  RESULTS
  With the investigation of individual risk factors, as well as their incorporation into risk prediction models, the NHS has contributed to the identification of ways in which women may reduce breast cancer risk, including limiting alcohol consumption, reducing the duration of postmenopausal estrogen-plus-progestin use, avoiding weight gain, and increasing vegetable consumption. In addition, the NHS has helped elucidate the roles of several biomarkers and contributed to the identification of risk alleles.
  
  
  CONCLUSIONS
  The NHS has contributed to our understanding of lifestyle, hormonal, and genetic risk factors for breast cancer, highlighting the importance of exposures across the life course, and has helped identify lifestyle changes that may reduce risk and improve survival after a diagnosis of breast cancer.
authors.affiliation: Megan S. Rice is with the Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA. A. Heather Eliassen and Rulla M. Tamimi are with the Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston. Elizabeth B. Lenart and Walter C. Willett are with the Department of Nutrition, Harvard T. H. Chan School of Public Health, Boston. Susan E. Hankinson is with the Division of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts, Amherst.
authors.forename: Megan S
authors.initials: MS
authors.lastname: Rice
authors.affiliation: Megan S. Rice is with the Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA. A. Heather Eliassen and Rulla M. Tamimi are with the Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston. Elizabeth B. Lenart and Walter C. Willett are with the Department of Nutrition, Harvard T. H. Chan School of Public Health, Boston. Susan E. Hankinson is with the Division of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts, Amherst.
authors.forename: A Heather
authors.initials: AH
authors.lastname: Eliassen
authors.affiliation: Megan S. Rice is with the Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA. A. Heather Eliassen and Rulla M. Tamimi are with the Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston. Elizabeth B. Lenart and Walter C. Willett are with the Department of Nutrition, Harvard T. H. Chan School of Public Health, Boston. Susan E. Hankinson is with the Division of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts, Amherst.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Hankinson
authors.affiliation: Megan S. Rice is with the Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA. A. Heather Eliassen and Rulla M. Tamimi are with the Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston. Elizabeth B. Lenart and Walter C. Willett are with the Department of Nutrition, Harvard T. H. Chan School of Public Health, Boston. Susan E. Hankinson is with the Division of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts, Amherst.
authors.forename: Elizabeth B
authors.initials: EB
authors.lastname: Lenart
authors.affiliation: Megan S. Rice is with the Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA. A. Heather Eliassen and Rulla M. Tamimi are with the Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston. Elizabeth B. Lenart and Walter C. Willett are with the Department of Nutrition, Harvard T. H. Chan School of Public Health, Boston. Susan E. Hankinson is with the Division of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts, Amherst.
authors.forename: Walter C
authors.initials: WC
authors.lastname: Willett
authors.affiliation: Megan S. Rice is with the Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA. A. Heather Eliassen and Rulla M. Tamimi are with the Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston. Elizabeth B. Lenart and Walter C. Willett are with the Department of Nutrition, Harvard T. H. Chan School of Public Health, Boston. Susan E. Hankinson is with the Division of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts, Amherst.
authors.forename: Rulla M
authors.initials: RM
authors.lastname: Tamimi
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000453:epidemiology*; D016021:Epidemiologic Studies; D005260:Female; D006801:Humans; D008019:Life Style; D008137:Longitudinal Studies; D008875:Middle Aged; D009726:Nurses; D011446:Prospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D016387:Women's Health