title: Adverse associations of car time with markers of cardio-metabolic risk.
abstract: OBJECTIVE
  To examine associations of time spent sitting in cars with markers of cardio-metabolic risk in Australian adults.
  
  
  METHODS
  Data were from 2800 participants (age range: 34-65) in the 2011-12 Australian Diabetes, Obesity and Lifestyle Study. Self-reported time spent in cars was categorized into four groups: ≤15min/day; >15 to ≤30min/day; >30 to ≤60min/day; and >60min/day. Markers of cardio-metabolic risk were body mass index (BMI), waist circumference, systolic and diastolic blood pressure, triglycerides, HDL (high-density lipoprotein)-cholesterol, fasting plasma glucose, 2-h plasma glucose, a clustered cardio-metabolic risk score, and having the metabolic syndrome or not. Multilevel linear and logistic regression analyses examined associations of car time with each cardio-metabolic risk outcome, adjusting for socio-demographic and behavioral variables and medication use for blood pressure and cholesterol/triglycerides.
  
  
  RESULTS
  Compared to spending 15min/day or less in cars, spending more than 1h/day in cars was significantly associated with higher BMI, waist circumference, fasting plasma glucose, and clustered cardio-metabolic risk, after adjusting for socio-demographic attributes and potentially relevant behaviors including leisure-time physical activity and dietary intake. Gender interactions showed car time to be associated with higher BMI in men only.
  
  
  CONCLUSIONS
  Prolonged time spent sitting in cars, in particular over 1h/day, was associated with higher total and central adiposity and a more-adverse cardio-metabolic risk profile. Further studies, ideally using objective measures of sitting time in cars and prospective designs, are needed to confirm the impact of car use on cardio-metabolic disease risk.
authors.affiliation: Centre for Design Innovation, Faculty of Health Arts & Design, Swinburne University of Technology, Melbourne, VIC, Australia; School of Population Health, University of South Australia, Adelaide, SA, Australia; Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia; Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia. Electronic address: tsugiyama@swin.edu.au.
authors.forename: Takemi
authors.initials: T
authors.lastname: Sugiyama
authors.affiliation: MRC Epidemiology Unit, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Katrien
authors.initials: K
authors.lastname: Wijndaele
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia; Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia.
authors.forename: Mohammad Javad
authors.initials: MJ
authors.lastname: Koohsari
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia.
authors.forename: Stephanie K
authors.initials: SK
authors.lastname: Tanamas
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia; School of Exercise and Nutrition Sciences, Deakin University, Burwood, VIC, Australia; School of Population Health, The University of QLD, Brisbane, QLD, 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 of Health Research, Australian Catholic University, Melbourne, VIC, Australia.
authors.forename: David W
authors.initials: DW
authors.lastname: Dunstan
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia; Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia; School of Population Health, The University of QLD, Brisbane, QLD, Australia; Central Clinical School, Monash University, Melbourne, VIC, Australia.
authors.forename: Neville
authors.initials: N
authors.lastname: Owen
mesh_terms: D000328:Adult; D000368:Aged; D001315:Australia; D001334:Automobile Driving; D015415:Biomarkers / Q000097:blood*; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000097:blood*; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood*; D008875:Middle Aged; D012307:Risk Factors; D057185:Sedentary Behavior; D013997:Time Factors; D055105:Waist Circumference / Q000502:physiology
chemical_list: D015415:Biomarkers
keywords: Adiposity; Automobile; Motorized transport; Sedentary behavior