title: Validity of a multi-context sitting questionnaire across demographically diverse population groups: AusDiab3.
abstract: BACKGROUND
  Sitting time questionnaires have largely been validated in small convenience samples. The validity of this multi-context sitting questionnaire against an accurate measure of sitting time is reported in a large demographically diverse sample allowing assessment of validity in varied demographic subgroups.
  
  
  METHODS
  A subgroup of participants of the third wave of the Australian Diabetes, Obesity, and Lifestyle (AusDiab3) study wore activPAL3™ monitors (7 days, 24 hours/day protocol) and reported their sitting time for work, travel, television viewing, leisure computer use and "other" purposes, on weekdays and weekend days (n = 700, age 36-89 years, 45% men). Correlations (Pearson's r; Spearman's ρ) of the self-report measures (the composite total, contextual measures and items) with monitor-assessed sitting time were assessed in the whole sample and separately in socio-demographic subgroups. Agreement was assessed using Bland-Altman plots.
  
  
  RESULTS
  The composite total had a correlation with monitor-assessed sitting time of r = 0.46 (95% confidence interval [CI]: 0.40, 0.52); this correlation did not vary significantly between demographic subgroups (all >0.4). The contextual measure most strongly correlated with monitor-assessed sitting time was work (ρ = 0.25, 95 % CI: 0.17, 0.31), followed by television viewing (ρ = 0.16, 95 % CI: 0.09, 0.24). Agreement of the composite total with monitored sitting time was poor, with a positive bias (B = 0.53, SE 0.04, p < 0.001) and wide limits of agreement (±4.32 h).
  
  
  CONCLUSIONS
  This multi-context questionnaire provides a total sitting time measure that ranks participants well for the purposes of assessing health associations but has limited accuracy relative to activPAL-assessed sitting time. Findings did not differ in demographic subgroups.
authors.affiliation: The University of Queensland, School of Public Health, Brisbane, Queensland, Australia. b.clark3@uq.edu.au.
authors.forename: Bronwyn K
authors.initials: BK
authors.lastname: Clark
authors.affiliation: Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, Australia.|Melbourne School of Population and Global Health, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Australia.|Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia.
authors.forename: Brigid M
authors.initials: BM
authors.lastname: Lynch
authors.affiliation: The University of Queensland, School of Public Health, Brisbane, Queensland, Australia.
authors.forename: Elisabeth Ah
authors.initials: EA
authors.lastname: Winkler
authors.affiliation: The University of Queensland, School of Public Health, Brisbane, Queensland, Australia.|Mater Research Institute - The University of Queensland, Brisbane, QLD, Australia.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Gardiner
authors.affiliation: The University of Queensland, School of Public Health, Brisbane, Queensland, Australia.|Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia.|Curtin University, School of Physiotherapy, Perth, Western Australia, Australia.
authors.forename: Genevieve N
authors.initials: GN
authors.lastname: Healy
authors.affiliation: The University of Queensland, School of Public Health, Brisbane, Queensland, Australia.|Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia.|Curtin University, School of Physiotherapy, Perth, Western Australia, Australia.|School of Exercise and Nutrition Sciences, Deakin University, Burwood, VIC, Australia.|Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia.|School of Sport Science, Exercise and Health, The University of Western Australia, Perth, WA, Australia.|Central Clinical School, Monash University, Melbourne, VIC, Australia.|Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, Australia.
authors.forename: David W
authors.initials: DW
authors.lastname: Dunstan
authors.affiliation: The University of Queensland, School of Public Health, Brisbane, Queensland, Australia.|Melbourne School of Population and Global Health, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Australia.|Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia.|Central Clinical School, Monash University, Melbourne, VIC, Australia.
authors.forename: Neville
authors.initials: N
authors.lastname: Owen
mesh_terms: D056044:Actigraphy / Q000706:statistics & numerical data; D000328:Adult; D017677:Age Distribution; D000368:Aged; D001315:Australia; D003710:Demography / Q000706:statistics & numerical data*; D004651:Employment / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008393:Marriage / Q000706:statistics & numerical data; D008875:Middle Aged; D011187:Posture / Q000502:physiology*; D015203:Reproducibility of Results; D057185:Sedentary Behavior; D057566:Self Report; D017678:Sex Distribution; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires / Q000592:standards*; D013995:Time