title: Association between change in daily ambulatory activity and cardiovascular events in people with impaired glucose tolerance (NAVIGATOR trial): a cohort analysis.
abstract: BACKGROUND
  The extent to which change in physical activity can modify the risk of cardiovascular disease in individuals at high cardiovascular risk is uncertain. We investigated whether baseline and change in objectively-assessed ambulatory activity is associated with the risk of a cardiovascular event in individuals at high cardiovascular risk with impaired glucose tolerance.
  
  
  METHODS
  We assessed prospective data from the NAVIGATOR trial involving 9306 individuals with impaired glucose tolerance who were recruited in 40 countries between January, 2002, and January, 2004. Participants also either had existing cardiovascular disease (if age ≥50 years) or at least one additional cardiovascular risk factor (if age ≥55 years). Participants were followed-up for cardiovascular events (defined as cardiovascular mortality, non-fatal stroke, or myocardial infarction) for 6 years on average and had ambulatory activity assessed by pedometer at baseline and 12 months. Adjusted Cox proportional hazard models quantified the association of baseline and change in ambulatory activity (from baseline to 12 months) with the risk of a subsequent cardiovascular event, after adjustment for each other and potential confounding variables. This study is registered with ClinicalTrials.govNCT00097786.
  
  
  RESULTS
  During 45,211 person-years follow-up, 531 cardiovascular events occurred. Baseline ambulatory activity (hazard ratio [HR] per 2000 steps per day 0·90, 95% CI 0·84-0·96) and change in ambulatory activity (0·92, 0·86-0·99) were inversely associated with the risk of a cardiovascular event. Results for change in ambulatory activity were unaffected when also adjusted for changes in body-mass index and other potential confounding variables at 12 months.
  
  
  CONCLUSIONS
  In individuals at high cardiovascular risk with impaired glucose tolerance, both baseline levels of daily ambulatory activity and change in ambulatory activity display a graded inverse association with the subsequent risk of a cardiovascular event.
  
  
  BACKGROUND
  Novartis Pharmaceuticals.
authors.affiliation: NIHR Leicester-Loughborough Diet, Lifestyle, and Physical Activity Biomedical Research Unit, Leicester, UK; Leicester Diabetes Centre, College of Medicine, Biological Sciences and Psychology, University of Leicester, Leicester, UK. Electronic address: ty20@le.ac.uk.
authors.forename: Thomas
authors.initials: T
authors.lastname: Yates
authors.affiliation: Shavano Park, USA.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Haffner
authors.affiliation: Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA.
authors.forename: Phillip J
authors.initials: PJ
authors.lastname: Schulte
authors.affiliation: Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA.
authors.forename: Laine
authors.initials: L
authors.lastname: Thomas
authors.affiliation: Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA.
authors.forename: Kim M
authors.initials: KM
authors.lastname: Huffman
authors.affiliation: Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA; Durham VA Medical Center, Durham, NC, USA.
authors.forename: Connie W
authors.initials: CW
authors.lastname: Bales
authors.affiliation: Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Califf
authors.affiliation: Diabetes Trials Unit, University of Oxford, Oxford, UK.
authors.forename: Rury R
authors.initials: RR
authors.lastname: Holman
authors.affiliation: British Heart Foundation Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, UK.
authors.forename: John J V
authors.initials: JJ
authors.lastname: McMurray
authors.affiliation: Diabetes Trials Unit, University of Oxford, Oxford, UK.
authors.forename: M Angelyn
authors.initials: MA
authors.lastname: Bethel
authors.affiliation: Centre for Vascular Prevention, Danube University Krems, Krems, Austria; South Ostrobothnia Central Hospital, Seinajoki, Finland; King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Jaakko
authors.initials: J
authors.lastname: Tuomilehto
authors.affiliation: NIHR Leicester-Loughborough Diet, Lifestyle, and Physical Activity Biomedical Research Unit, Leicester, UK; Leicester Diabetes Centre, College of Medicine, Biological Sciences and Psychology, University of Leicester, Leicester, UK.
authors.forename: Melanie J
authors.initials: MJ
authors.lastname: Davies
authors.affiliation: Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA.
authors.forename: William E
authors.initials: WE
authors.lastname: Kraus
mesh_terms: D000368:Aged; D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000517:prevention & control; D015331:Cohort Studies; D005260:Female; D018149:Glucose Intolerance; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009203:Myocardial Infarction / Q000453:epidemiology / Q000517:prevention & control; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology / Q000517:prevention & control; D016138:Walking / Q000706:statistics & numerical data*