Measurement of Active and Sedentary Behavior in Context of Large Epidemiologic Studies.

Introduction/Purpose: To assess the utility of measurement methods that may be more accurate and precise than traditional questionnaire-based estimates of habitual physical activity and sedentary behavior we compared the measurement properties of a past year questionnaire (AARP) and more comprehensive measures: an internet-based 24-hour recall (ACT24), and a variety of estimates from an accelerometer (ActiGraph). Methods: Participants were 932 adults (50-74 y) in a 12-month study that included reference measures of energy expenditure from doubly labeled water (DLW) and active and sedentary time via activPAL. Results: Accuracy at the group level (mean differences) was generally better for both ACT24 and ActiGraph than the AARP questionnaire. AARP accuracy for energy expenditure ranged from -4 to -13% lower than DLW, but its accuracy was poorer for physical activity duration (-48%) and sedentary time (-18%) vs. activPAL. In contrast, ACT24 accuracy was within 3 to 10% of DLW expenditure measures and within 1 to 3% of active and sedentary time from activPAL. For ActiGraph, accuracy for energy expenditure was best for the Crouter 2-regression method (-2 to -7%), and for active and sedentary time the 100 count/minute cut-point was most accurate (-1% to 2%) at the group level. One administration of the AARP questionnaire was significantly correlated with long-term average from the reference measures ([rho]XT=0.16-0.34) overall, but 4 ACT24 recalls had higher correlations ([rho]XT=0.48-0.60), as did 4-days of ActiGraph assessment ([rho]XT=0.54-0.87). Conclusion: New exposure assessments suitable for use in large epidemiologic studies (ACT24, ActiGraph) were more accurate and had higher correlations than a traditional questionnaire. Use of better more comprehensive measures in future epidemiologic studies could yield new etiologic discoveries and possibly new opportunities for prevention. (C) 2017 American College of Sports Medicine

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