title: Sedentary behavior, health-related quality of life, and fatigue among breast cancer survivors.
abstract: BACKGROUND
  Many cancer survivors experience declines in health-related quality of life (HRQOL) and increases in fatigue as a result of cancer and its treatment. Exercise is linked to improvements in these outcomes, but little is known about the role of sedentary behavior. In a large, ethnically-diverse cohort of breast cancer survivors, we examined the relationship between sedentary time, HRQOL, and fatigue, and examined if that relationship differed by recreational moderate-vigorous physical activity (MVPA) level.
  
  
  METHODS
  Participants were 710 women diagnosed with stage 0-IIIA breast cancer in the Health, Eating, Activity, and Lifestyle Study. Women completed questionnaires at approximately 30-months postdiagnosis (sedentary time; recreational MVPA) and 41-months postdiagnosis (HRQOL; fatigue). In multivariate models, we regressed these outcomes linearly on quartiles of daily sedentary time, and a variable jointly reflecting sedentary time quartiles and MVPA categories (0; >0 to <9; ≥9 MET-hrs/wk).
  
  
  RESULTS
  Sedentary time was not independently related to subscales or summary scores of HRQOL or fatigue. In addition, comparisons of women with high vs. low (Q4:Q1) sedentary time by MVPA level did not result in significant differences in HRQOL or fatigue.
  
  
  CONCLUSIONS
  In this breast cancer survivor cohort, self-reported sedentary time was not associated with HRQOL or fatigue, 3.5 years postdiagnosis.
authors: Division of Cancer Control and Population Sciences, National Cancer Institute, Bethesda, MD, USA.
authors: Stephanie M
authors: SM
authors: George
authors: Catherine M
authors: CM
authors: Alfano
authors: Ashley
authors: A
authors: Wilder Smith
authors: Melinda L
authors: ML
authors: Irwin
authors: Anne
authors: A
authors: McTiernan
authors: Leslie
authors: L
authors: Bernstein
authors: Kathy B
authors: KB
authors: Baumgartner
authors: Rachel
authors: R
authors: Ballard-Barbash
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000453:epidemiology / Q000523:psychology* / Q000628:therapy*; D015444:Exercise / Q000502:physiology; D005221:Fatigue / Q000453:epidemiology*; D005260:Female; D006801:Humans; D011446:Prospective Studies; D011788:Quality of Life; D012042:Registries; D012307:Risk Factors; D018426:SEER Program; D057185:Sedentary Behavior; D011795:Surveys and Questionnaires; D017741:Survivors / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology