title: Systemic inflammation as a function of the individual and combined associations of sedentary behaviour, physical activity and cardiorespiratory fitness.
abstract: BACKGROUND
  Previous research demonstrates individual associations of sedentary behaviour, moderate-to-vigorous physical activity (MVPA) and cardiorespiratory fitness on systemic inflammation, often assessed via C-reactive protein (CRP) levels. Their potential additive association on CRP, however, has not been fully evaluated, which was the purpose of this study.
  
  
  METHODS
  Data from the 2003-2004 National Health and Nutrition Examination Survey were used (N = 627 adults 20-49 years). Sedentary behaviour and MVPA were objectively assessed (accelerometry) with cardiorespiratory fitness determined from a submaximal treadmill-based test. Participants were classified as above or below the median values for each of these three parameters, with a PACS (Physical Activity Cardiorespiratory Sedentary) score ranging from 0 to 3, indicating the participant number of these three positive characteristics. A blood sample was obtained from each participant to assess CRP via latex-enhanced nephelometry.
  
  
  RESULTS
  Above median sedentary behaviour (OR = 1·04; 95% CI: 0·65-1·66) was not associated with elevated (>0·3 mg dl-1) CRP, but above median MVPA (OR = 0·62; 95% CI: 0·40-0·97) and above median VO2max(OR = 0·61; 95% CI: 0·40-0·93) were associated with a reduced odds of having an elevated CRP. With regard to the additive model, and after adjustment, the odds ratios (95% CI) for the PACS score of 1 (versus 0), 2 (versus 0) and 3 (versus 0), respectively, were 0·59 (0·34-1·05; P = 0·07), 0·60 (0·31-1·15; P = 0·11) and 0·34 (0·12-0·97; P = 0·04).
  
  
  CONCLUSIONS
  Cardiorespiratory fitness and MVPA, but not sedentary behaviour, were independently associated with reduced odds of elevated CRP. Adults with all three characteristics, however, had the lowest odds of elevated CRP.
authors: Physical Activity Epidemiology Laboratory, Department of Health, Exercise Science and Recreation Management, The University of Mississippi, University, MS, USA.
authors: Meghan K
authors: MK
authors: Edwards
authors: Physical Activity Epidemiology Laboratory, Department of Health, Exercise Science and Recreation Management, Jackson Heart Study Vanguard Center of Oxford, The University of Mississippi, University, MS, USA.
authors: Paul D
authors: PD
authors: Loprinzi
mesh_terms: D056044:Actigraphy; D000328:Adult; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis*; D000072599:Cardiorespiratory Fitness; D015444:Exercise; D005080:Exercise Test; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D018836:Inflammation Mediators / Q000097:blood*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009391:Nephelometry and Turbidimetry; D009749:Nutrition Surveys; D016017:Odds Ratio; D012307:Risk Factors; D057185:Sedentary Behavior; D014481:United States / Q000453:epidemiology; D015854:Up-Regulation; D055815:Young Adult
chemical_list: D015415:Biomarkers; D018836:Inflammation Mediators; D002097:C-Reactive Protein
keywords: epidemiology; exercise; inflammation