title: Sleep and survival among women with breast cancer: 30 years of follow-up within the Nurses' Health Study.
abstract: Breast cancer is a leading cause of cancer death in women. Sleep has been linked with mortality among cancer-free population; however, its association with survival among women with breast cancer is understudied.
  
  
  
  Breast cancer patients (N=3682) reported their average sleep duration post diagnosis. Subsamples also provided their pre-diagnosis sleep duration (n=1949) and post-diagnosis sleep difficulties (n=1353). Multivariate Cox models estimated hazard ratios (HR) and confidence intervals (CI) of all-cause, breast cancer, and non-breast cancer mortality.
  
  
  
  At diagnosis, the mean age was 64.9 years and 91.7% were stage I or II. Women sleeping ⩾9 h per night post diagnosis had a strong higher risk of all-cause (multivariate HRs: MV-HR=1.37, CI=1.10-1.71), breast cancer (MV-HR=1.46, CI=1.02-2.07), and non-breast cancer mortality (MV-HR=1.34, CI=1.01-1.79), compared to women sleeping 8 h per night. Increased sleep duration post diagnosis (vs unchanged) and regular sleep difficulties (vs rare/none) were associated with a strong elevated risk of all-cause mortality (MV-HRincreased duration=1.35, CI=1.04-1.74; MV-HRregular difficulties=1.49, CI=1.02-2.19) and a moderate greater risk of breast cancer and non-breast cancer mortality.
  
  
  
  Various facets of sleep were associated with higher all-cause mortality risk. If replicated, these findings support evaluation of breast cancer patients' sleep duration and difficulties to identify those at risk for poorer outcomes.
authors.affiliation: Department of Social and Behavioral Sciences, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
authors.forename: Claudia
authors.initials: C
authors.lastname: Trudel-Fitzgerald
authors.affiliation: Department of Medicine, Harvard Medical School, 25 Shattuck St, Boston, MA 02115, USA.|Department of Medical Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Zhou
authors.affiliation: Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Poole
authors.affiliation: Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
authors.forename: Xuehong
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Epidemiology, UCLA Fielding School of Public Health, 650 Charles E Young Dr S, Los Angeles, CA 90095, USA.
authors.forename: Karin B
authors.initials: KB
authors.lastname: Michels
authors.affiliation: Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
authors.forename: A Heather
authors.initials: AH
authors.lastname: Eliassen
authors.affiliation: Department of Medicine, Harvard Medical School, 25 Shattuck St, Boston, MA 02115, USA.|Department of Medical Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA.|Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: Wendy Y
authors.initials: WY
authors.lastname: Chen
authors.affiliation: Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
authors.forename: Michelle D
authors.initials: MD
authors.lastname: Holmes
authors.affiliation: Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
authors.forename: Shelley S
authors.initials: SS
authors.lastname: Tworoger
authors.affiliation: Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.|Department of Epidemiology, Medical University of Vienna, Marianneng. 14/Top 105, Vienna 1090, Austria.
authors.forename: Eva S
authors.initials: ES
authors.lastname: Schernhammer
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000401:mortality / Q000503:physiopathology*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology / Q000503:physiopathology*; D016016:Proportional Hazards Models; D012307:Risk Factors; D012890:Sleep / Q000502:physiology*; D013997:Time Factors