PURPOSE: To assess the reproducibility and validity of a single-item, self-administered questionnaire on walking used in two population-based prospective cohort studies in northern Japan, using pedometer counts as the reference standard. METHODS: Fifty-one men and 55 women participating in the main cohort studies (mean age: 61.7 years) responded to a question on the average duration of walking per day five times at 3-month intervals. The subjects also provided 3 consecutive days of pedometer counts four times along with the first four questionnaire surveys. RESULTS: For the first and the fifth questionnaires administered one year apart, 55% of the subjects chose concordant categories among three options (=<30 min / between 30 and 60 min / >= 60 min), and 13% chose the highest category in one questionnaire and the lowest in the other questionnaire. The sex- and age-adjusted mean daily numbers of walking steps counted by the pedometer were 5,857, 7,047, and 7,621 for the three categories of walking duration in the fifth questionnaire, and it showed significant linear associations with all of the five questionnaire measurements. CONCLUSON: The single-item questionnaire on walking is reasonably reproducible and valid, and useful in studying the health effects of walking among the Japanese population.
- Physical activity