title: Associations between accelerometer-assessed sedentary behavior, physical activity and objectively-measured cardiorespiratory fitness with red blood cell distribution width.
abstract: BACKGROUND
  Emerging work identifies red blood cell distribution width (RDW) as a unique biomarker independently associated with cardiovascular disease and mortality. Encouragingly, recent research demonstrates individual associations of sedentary behavior, physical activity and cardiorespiratory fitness with RDW. However, no study has evaluated their independent and combined associations on RDW, which was this study's purpose.
  
  
  METHODS
  Data from the 2003-2004 National Health and Nutrition Examination Survey were used (N=627 adults 20-49yrs). Sedentary behavior 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 RDW.
  
  
  RESULTS
  Only above median MVPA (OR=0.47; 95% CI: 0.32-0.68) was independently associated with a reduced odds of having an elevated RDW. With regard to the additive model, and after adjustment, the odds ratio (95% CI) for the PACS score of 1 (vs. 0), 2 (vs. 0), and 3 (vs. 0), respectively, were 0.81 (0.45-1.45; P=0.46), 0.66 (0.44-0.99; P=0.04) and 0.35 (0.18-0.68; P=0.004).
  
  
  CONCLUSIONS
  When considering sedentary behavior, MVPA, and cardiorespiratory fitness, only MVPA was associated with reduced odds of elevated RDW, but those with all three characteristics had the lowest odds of elevated RDW.
authors.affiliation: Physical Activity Epidemiology Laboratory, Department of Health, Exercise Science and Recreation Management, The University of Mississippi, University, MS 38677, United States.
authors.forename: Meghan K
authors.initials: MK
authors.lastname: Edwards
authors.affiliation: Jackson Heart Study Vanguard Center of Oxford, Physical Activity Epidemiology Laboratory, Department of Health, Exercise Science and Recreation Management, The University of Mississippi, University, MS 38677, United States. Electronic address: pdloprin@olemiss.edu.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Loprinzi
mesh_terms: D061725:Accelerometry / Q000379:methods*; D000328:Adult; D015415:Biomarkers / Q000097:blood; D000072599:Cardiorespiratory Fitness / Q000502:physiology*; D002318:Cardiovascular Diseases / Q000097:blood / Q000175:diagnosis; D048429:Cell Size; D004909:Erythrocyte Indices / Q000502:physiology*; D004912:Erythrocytes / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys / Q000379:methods; D010809:Physical Fitness / Q000502:physiology; D057185:Sedentary Behavior; D055815:Young Adult
chemical_list: D015415:Biomarkers
keywords: Epidemiology; Exercise; Inflammation