[Validity and reproducibility of a physical activity questionnaire used for health surveying among victims of the Great East Japan Earthquake].

This study was performed to assess the validity and reproducibility of a questionnaire on physical activity status used for health surveying among victims of the Great East Japan Earthquake. Seventy-four residents (21 men and 53 women) living in temporary housing in Kamaishi City, Iwate Prefecture, participated in this study. The physical activity status questionnaire was composed of 4 questions regarding the frequency of performing domestic and occupational physical activities, the frequency of leaving their residence, walking duration per day, and sedentary time. The physical activity level for 2 weeks was measured using a tri-accelerometer to validate the responses to the questionnaire. Test-retest reproducibility was examined at 2-week intervals. The physical activity levels were 4,521 +/- 2,266 steps/day for men and 4,533 +/- 2,070 steps/day for women. There was a significant difference in step count between those responding differently to the 3 options in the questionnaire regarding average walking duration per day: those who reported walking for > or = 60 min, 30-60 min, or < or = 30 min had step counts of 5,343 +/- 1,757, 4,760 +/- 1,752, and 3,063 +/- 1,772 steps/day, respectively (P < 0.05). When the response options for 3 questions (excluding those for sedentary time) were given scores (a higher score for a higher physical activity level), there were significant correlations between question score and step count (r = 0.486, P < 0.05) and the amount of moderate to vigorous physical activity (r = 0.342, P < 0.05). The test-retest trial showed a moderate degree of reproducibility, with weighted K coefficients of 0.41-0.65. Three questions on physical activity levels may allow assessment of an individual's physical activity level, with a moderate degree of reproducibility.