title: Validation of an Internet-based long version of the International Physical Activity Questionnaire in Danish adults using combined accelerometry and heart rate monitoring.
abstract: BACKGROUND
  The International Physical Activity Questionnaire (IPAQ) is commonly used in surveys, but reliability and validity has not been established in the Danish population.
  
  
  METHODS
  Among participants in the Danish Health Examination survey 2007-2008, 142 healthy participants (45% men) wore a unit that combined accelerometry and heart rate monitoring (Acc+HR) for 7 consecutive days and then completed the IPAQ. Background data were obtained from the survey. Physical activity energy expenditure (PAEE) and time in moderate, vigorous, and sedentary intensity levels were derived from the IPAQ and compared with estimates from Acc+HR using Spearman's correlation coefficients and Bland-Altman plots. Repeatability of the IPAQ was also assessed.
  
  
  RESULTS
  PAEE from the 2 methods was significantly positively correlated (0.29 and 0.49; P = 0.02 and P < 0.001; for women and men, respectively). Men significantly overestimated PAEE by IPAQ (56.2 vs 45.3 kJ/kg/day, IPAQ: Acc+HR, P < .01), while the difference was nonsignificant for women (40.8 vs 44.4 kJ/kg/day). Bland-Altman plots showed that the IPAQ overestimated PAEE, moderate, and vigorous activity without systematic error. Reliability of the IPAQ was moderate to high for all domains and intensities (total PAEE intraclass correlation coefficient = 0.58).
  
  
  CONCLUSIONS
  This Danish Internet-based version of the long IPAQ had modest validity and reliability when assessing PAEE at population level.
authors: National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark.
authors: Andreas Wolff
authors: AW
authors: Hansen
authors: Inger
authors: I
authors: Dahl-Petersen
authors: Jørn Wulff
authors: JW
authors: Helge
authors: Søren
authors: S
authors: Brage
authors: Morten
authors: M
authors: Grønbæk
authors: Trine
authors: T
authors: Flensborg-Madsen
mesh_terms: D061725:Accelerometry / Q000592:standards* / Q000706:statistics & numerical data; D000328:Adult; D003718:Denmark; D004734:Energy Metabolism; D005260:Female; D006306:Health Surveys; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D020407:Internet; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*; D055815:Young Adult