title: Relative validity and repeatability of a new questionnaire on physical activity.
abstract: BACKGROUND
  A physical activity questionnaire was developed with the aim to estimate usual individual daily energy expenditure. The questionnaire focused on the number of hours usually spent on various activities. In a pilot study it was tested for repeatability and validity in a population of 126 Dutch adults (64 men, 62 women).
  
  
  METHODS
  For assessment of repeatability the questionnaire was administered three times during the course of 1 year. A four-times-repeated 3-day activity diary was used as a reference instrument to evaluate validity.
  
  
  RESULTS
  Differences in mean energy expenditure among repeated administrations of the questionnaire were small and not significant. Spearman's test-retest correlation coefficients for total energy expenditure for men were 0.76 [95% confidence interval (CI) 0.63-0.85] and 0.70 (95% CI 0.54-0.81) at 5 and 11 months, respectively, and for women were 0.58 (95% CI 0.36-0.74) and 0.71 (95% CI 0.54-0.82). There was a significant trend showing increasing mean diary energy expenditure for successive tertiles of questionnaire energy expenditure. The correlation between the questionnaire and the diary was 0.66 (95% CI 0.49-0.78) for men and 0.43 (95% CI 0.18-0.63) for women.
  
  
  CONCLUSIONS
  It was concluded that this questionnaire is a useful tool for estimating energy expenditure in epidemiological studies.
authors.affiliation: Department of Epidemiology, Faculty of Medicine, Utrecht University, The Netherlands.
authors.forename: M A
authors.initials: MA
authors.lastname: Pols
authors.forename: P H
authors.initials: PH
authors.lastname: Peeters
authors.forename: M C
authors.initials: MC
authors.lastname: Ocké
authors.forename: H B
authors.initials: HB
authors.lastname: Bueno-de-Mesquita
authors.forename: N
authors.initials: N
authors.lastname: Slimani
authors.forename: H C
authors.initials: HC
authors.lastname: Kemper
authors.forename: H J
authors.initials: HJ
authors.lastname: Collette
mesh_terms: D000328:Adult; D000368:Aged; D004734:Energy Metabolism; D015444:Exercise; D005260:Female; D015438:Health Behavior; D006801:Humans; D007899:Leisure Activities; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D009790:Occupations; D010865:Pilot Projects; D011594:Psychometrics; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires