title: Self-Reported Versus Accelerometer-Measured Physical Activity and Biomarkers Among NHANES Youth.
abstract: BACKGROUND
  Discrepancies in self-report and accelerometer-measured moderate-to-vigorous physical activity (MVPA) may influence relationships with obesity-related biomarkers in youth.
  
  
  METHODS
  Data came from 2003-2006 National Health and Nutrition Examination Surveys (NHANES) for 2174 youth ages 12 to 19. Biomarkers were: body mass index (BMI, kg/m2), BMI percentile, height and waist circumference (WC, cm), triceps and subscapular skinfolds (mm), systolic & diastolic blood pressure (BP, mmHg), high-density lipoprotein (HDL, mg/dL), total cholesterol (mg/dL), triglycerides (mg/dL), insulin (μU/ml), C-reactive protein (mg/dL), and glycohemoglobin (%). In separate sex-stratified models, each biomarker was regressed on accelerometer variables [mean MVPA (min/day), nonsedentary counts, and MVPA bouts (mean min/day)] and self-reported MVPA. Covariates were age, race/ethnicity, SES, physical limitations, and asthma.
  
  
  RESULTS
  In boys, correlations between self-report and accelerometer MVPA were stronger (boys: r = 0.14-0.21; girls: r = 0.07-0.11; P < .010) and there were significant associations with BMI, WC, triceps skinfold, and SBP and accelerometer MVPA (P < .01). In girls, there were no significant associations between biomarkers and any measures of physical activity.
  
  
  CONCLUSIONS
  Physical activity measures should be selected based on the outcome of interest and study population; however, associations between PA and these biomarkers appear to be weak regardless of the measure used.
authors.affiliation: Cancer Prevention Fellowship Program, Division of Cancer Prevention, Health Behaviors Research Branch, Behavioral Research Program, National Cancer Institute, Bethesda, MD.
authors.forename: Britni R
authors.initials: BR
authors.lastname: Belcher
authors.forename: Richard P
authors.initials: RP
authors.lastname: Moser
authors.forename: Kevin W
authors.initials: KW
authors.lastname: Dodd
authors.forename: Audie A
authors.initials: AA
authors.lastname: Atienza
authors.forename: Rachel
authors.initials: R
authors.lastname: Ballard-Barbash
authors.forename: David
authors.initials: D
authors.lastname: Berrigan
mesh_terms: D061725:Accelerometry / Q000295:instrumentation / Q000706:statistics & numerical data*; D000293:Adolescent; D015415:Biomarkers / Q000378:metabolism*; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000378:metabolism; D002784:Cholesterol / Q000097:blood; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009749:Nutrition Surveys; D009765:Obesity / Q000453:epidemiology; D057566:Self Report; D014280:Triglycerides / Q000097:blood; D055105:Waist Circumference / Q000502:physiology
chemical_list: D015415:Biomarkers; D007328:Insulin; D014280:Triglycerides; D002097:C-Reactive Protein; D002784:Cholesterol