title: Television viewing, walking speed, and grip strength in a prospective cohort study.
abstract: OBJECTIVE
  Television (TV) watching is the most prevalent sedentary leisure time activity in the United Kingdom. We examined associations between TV viewing time, measured over 10 yr, and two objective measures of physical capability, usual walking speed (UWS) and grip strength.
  
  
  METHODS
  Community-based participants (n = 8623; 48-92 yr old) enrolled in the European Prospective Investigation of Cancer-Norfolk study attended a third health examination (3HC, 2006-2011) for measurement of maximum grip strength (Smedley dynamometer) and UWS. TV viewing time was estimated using a validated questionnaire (n = 6086) administered during two periods (3HC, 2006-2007; 2HC, 1998-2000). Associations between physical capability and TV viewing time category (<2, 2 < 3, 3 < 4, and ≥4 h·d) at the 3HC, 2HC, and using an average of the two measures were explored. Sex-stratified analyses were adjusted for age, physical activity, anthropometry, wealth, comorbidity, smoking, and alcohol intake and combined if no sex-TV viewing time interactions were identified.
  
  
  RESULTS
  Men and women who watched the least TV at the 2HC or 3HC walked at a faster usual pace than those who watched the most TV. There was no evidence of effect modification by sex (Pinteraction = 0.09), and in combined analyses, participants who watched for <2 h·d on average walked 4.29 cm·s (95% confidence interval, 2.56-6.03) faster than those who watched for ≥4 h·d, with evidence of a dose-response association (Ptrend < 0.001). However, no strong associations with grip strength were found.
  
  
  CONCLUSIONS
  TV viewing time predicted UWS in older adults. More research is needed to inform public health policy and prospective associations between other measures of sedentariness, such as total sitting time or objectively measured sedentary time, and physical capability should be explored.
authors.affiliation: 1Strangeways Research Laboratory, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UNITED KINGDOM; 2Medical Research Council Epidemiology Unit, Institute of Metabolic Science, School of Clinical Medicine, University of Cambridge, Cambridge, UNITED KINGDOM; and 3Academic Geriatric Medicine, Medical Research Council Lifecourse Epidemiology Unit, Faculty of Medicine, University of Southampton, Southampton, UNITED KINGDOM.
authors.forename: Victoria L
authors.initials: VL
authors.lastname: Keevil
authors.forename: Katrien
authors.initials: K
authors.lastname: Wijndaele
authors.forename: Robert
authors.initials: R
authors.lastname: Luben
authors.forename: Avan A
authors.initials: AA
authors.lastname: Sayer
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Wareham
authors.forename: Kay-Tee
authors.initials: KT
authors.lastname: Khaw
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D018737:Hand Strength / Q000502:physiology*; D006291:Health Policy; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D057185:Sedentary Behavior; D013690:Television; D006113:United Kingdom; D016138:Walking / Q000502:physiology*