title: Sitting-time and 9-year all-cause mortality in older women.
abstract: BACKGROUND
  Studies of mid-aged adults provide evidence of a relationship between sitting-time and all-cause mortality, but evidence in older adults is limited. The aim is to examine the relationship between total sitting-time and all-cause mortality in older women.
  
  
  METHODS
  The prospective cohort design involved 6656 participants in the Australian Longitudinal Study on Women's Health who were followed for up to 9 years (2002, age 76-81, to 2011, age 85-90). Self-reported total sitting-time was linked to all-cause mortality data from the National Death Index from 2002 to 2011. Cox proportional hazard models were used to examine the relationship between sitting-time and all-cause mortality, with adjustment for potential sociodemographic, behavioural and health confounders.
  
  
  RESULTS
  There were 2003 (30.1%) deaths during a median follow-up of 6 years. Compared with participants who sat <4 h/day, those who sat 8-11 h/day had a 1.45 times higher risk of death and those who sat ≥11 h/day had a 1.65 times higher risk of death. These risks remained after adding sociodemographic and behavioural covariates, but were attenuated after adjustment for health covariates. A significant interaction (p=0.02) was found between sitting-time and physical activity (PA), with increased mortality risk for prolonged sitting only among participants not meeting PA guidelines (HR for sitting ≥8 h/day: 1.31, 95% CI 1.07 to 1.61); HR for sitting ≥11 h/day: 1.47, CI 1.15 to 1.93).
  
  
  CONCLUSIONS
  Prolonged sitting-time was positively associated with all-cause mortality. Women who reported sitting for more than 8 h/day and did not meet PA guidelines had an increased risk of dying within the next 9 years.
authors.affiliation: School of Human Movement Studies, University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Toby G
authors.initials: TG
authors.lastname: Pavey
authors.affiliation: School of Human Movement Studies, University of Queensland, Brisbane, Queensland, Australia School of Population Health, University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Gmee Geeske
authors.initials: GG
authors.lastname: Peeters
authors.affiliation: School of Human Movement Studies, University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Wendy J
authors.initials: WJ
authors.lastname: Brown
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001315:Australia; D002423:Cause of Death; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D011187:Posture / Q000502:physiology; D011446:Prospective Studies; D012307:Risk Factors; D057185:Sedentary Behavior; D012959:Socioeconomic Factors; D013997:Time Factors