title: Objectively Measured Daily Steps and Subsequent Long Term All-Cause Mortality: The Tasped Prospective Cohort Study.
abstract: BACKGROUND
  Self-reported physical activity has been inversely associated with mortality but the effect of objectively measured step activity on mortality has never been evaluated. The objective is to determine the prospective association of daily step activity on mortality among free-living adults.
  
  
  RESULTS
  Cohort study of free-living adults residing in Tasmania, Australia between 2000 and 2005 who participated in one of three cohort studies (n = 2 576 total participants). Daily step activity by pedometer at baseline at a mean of 58.8 years of age, and for a subset, repeated monitoring was available 3.7 (SD 1.3) years later (n = 1 679). All-cause mortality (n = 219 deaths) was ascertained by record-linkage to the Australian National Death Index; 90% of participants were followed-up over ten years, until June 2011. Higher daily step count at baseline was linearly associated with lower all-cause mortality (adjusted hazard ratio AHR, 0.94; 95% CI, 0.90 to 0.98 per 1 000 steps; P = 0.004). Risk was altered little by removing deaths occurring in the first two years. Increasing baseline daily steps from sedentary to 10 000 steps a day was associated with a 46% (95% CI, 18% to 65%; P = 0.004) lower risk of mortality in the decade of follow-up. In addition, those who increased their daily steps over the monitoring period had a substantial reduction in mortality risk, after adjusting for baseline daily step count (AHR, 0.39; 95% CI, 0.22 to 0.72; P = 0.002), or other factors (AHR, 0.38; 95% CI, 0.21-0.70; P = 0.002).
  
  
  CONCLUSIONS
  Higher daily step count was linearly associated with subsequent long term mortality among free living adults. These data are the first to quantify mortality reductions using an objective measure of physical activity in a free living population. They strongly underscore the importance of physical inactivity as a major public health problem.
authors.affiliation: The George Institute for Global Health, Oxford, United Kingdom.|Menzies Research Institute, University of Tasmania, Hobart, Tasmania, Australia.|Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.
authors.forename: Terence
authors.initials: T
authors.lastname: Dwyer
authors.affiliation: Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.
authors.forename: Angela
authors.initials: A
authors.lastname: Pezic
authors.affiliation: Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.|Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Cong
authors.initials: C
authors.lastname: Sun
authors.affiliation: Menzies Research Institute, University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: Jenny
authors.initials: J
authors.lastname: Cochrane
authors.affiliation: Menzies Research Institute, University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: Alison
authors.initials: A
authors.lastname: Venn
authors.affiliation: Stroke and Ageing Research Group, Medicine, School of Clinical Sciences, Monash University, Melbourne, Victoria, Australia.
authors.forename: Velandai
authors.initials: V
authors.lastname: Srikanth
authors.affiliation: Menzies Research Institute, University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: Graeme
authors.initials: G
authors.lastname: Jones
authors.forename: Robin P
authors.initials: RP
authors.lastname: Shook
authors.affiliation: Iowa State University of Science and Technology, Ames, Iowa, United States of America.
authors.forename: Robin
authors.initials: R
authors.lastname: Shook
authors.affiliation: Iowa State University of Science and Technology, Ames, Iowa, United States of America.|Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina, United States of America.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Sui
authors.affiliation: Iowa State University of Science and Technology, Ames, Iowa, United States of America.|Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina, United States of America.
authors.forename: Andrew
authors.initials: A
authors.lastname: Ortaglia
authors.affiliation: Iowa State University of Science and Technology, Ames, Iowa, United States of America.|Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina, United States of America.|Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina, United States of America.
authors.forename: Steven
authors.initials: S
authors.lastname: Blair
authors.affiliation: Menzies Research Institute, University of Tasmania, Hobart, Tasmania, Australia.|Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.|Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Anne-Louise
authors.initials: AL
authors.lastname: Ponsonby
mesh_terms: D056044:Actigraphy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009026:Mortality / Q000639:trends*; D009043:Motor Activity / Q000502:physiology*; D011446:Prospective Studies; D057566:Self Report; D013648:Tasmania; D016138:Walking