Validity and reliability of Japanese-language self-reported measures for assessing adults domain-specific sedentary time

Background: Good quality measures of Japanese adults' sedentary behaviors are needed to accurately assess correlates of specific sedentary behaviors. The present study assessed criterion validity of total sedentary behavior and test-retest reliability of six domain-specific sedentary behaviors. Methods: We administered a questionnaire, based on previous studies, that measured domain-specific sedentary behaviors. To examine validity, agreement between self-reported time spent in sedentary behaviors from the questionnaire and objectivelymeasured sedentary time using accelerometers was compared among 392 adults (aged 40-64 years) in two Japanese cities. For reliability, a 2-week interval test-retest was administered to a convenience sample of 34 participants. Results: The correlation between total self-reported and objectively measured sedentary time was significant (all P < 0.001) and fair-to-good for workdays (rho = 0.57) and whole week (rho = 0.49), but was low for non-workdays (rho = 0.23). The difference between the two measures was significant for whole week (z = -2.25, P = 0.03) and non-workdays (z = -5.50, P < 0.001), but was not significant for workdays (z = -0.60, P = 0.55). There was a significant positive association between the difference in the two measures and the average of these two measures (workdays: r = 0.53; non-workdays: r = 0.45; and whole week: r = 0.54, all P < 0.001). There was fair-to-good test-retest reliability of total sedentary time for each domain (workdays: interclass correlation coefficient [ICC] = 0.77, non-workdays: ICC = 0.53, and whole week: ICC = 0.7; all P < 0.01). Conclusions: The scale of domain-specific sedentary behaviors is reliable for estimating where and for what purpose Japanese adults spend their sedentary time, and total sedentary time is valid for workdays and the whole week.