Relative Validity and Repeatability of a New Questionnaire on Physical Activity,

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. Spearmanʹs 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.