Physical activity derived from questionnaires and wrist-worn accelerometers: comparability and the role of demographic, lifestyle, and health factors among a population-based sample of older adults

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  Figure 1. Flowchart of participant inclusion in the Rotterdam Study. Notes: *The Actiwatch (Actiwatch model AW4; Cambridge Technology, Cambridge, UK) is a one-dimensional device and cannot be used to measure physical activity.

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  Figure 2. Factors associated with level of disagreement (ie, absolute difference) between accelerometer and questionnaire physical activity. Notes: A positive difference indicates a larger absolute difference between the questionnaire and the accelerometer compared to the reference, whereas a negative difference indicates a smaller difference. Analyses included all demographics: lifestyle and health variables, total accelerometer-derived physical activity, time between interview date and first accelerometer-wear date, cohort, and wave. The coefficient for women was relative to men, and the coefficient for paid occupation relative to those without. For continuous variables (age, disability score, number of chronic diseases, MMSE score, and CESD score), values correspond to a 1-unit increase in the determinant. Abbreviations: BMI, body-mass index; CESD, Center for Epidemiologic Studies Depression; MMSE, Mini-Mental State Examination; PA: physical activity; ref, reference.

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  Figure 3. Factors associated with the direction of disagreement between accelerometer and questionnaire physical activity. Notes: Considering the average direction of disagreement equaled −529.4 minutes/week, positive disagreement indicates less underestimation in the questionnaire. relative to the accelerometer. Negative disagreement indicates more underestimation in the questionnaire compared to the accelerometer. Analyses included all demographic, lifestyle, and health variables, total accelerometer-derived physical activity, time between interview date and first accelerometer-wear date, cohort, and wave. The coefficient for women was relative to men and the coefficient for paid occupation relative to those without paid occupation. For continuous variables (age, disability score, number of chronic diseases, MMSE-score, and CESD-score), values correspond with a 1-unit increase in the determinant. Abbreviations: BMI, body-mass index; CESD, Center for Epidemiologic Studies Depression; MMSE, Mini-Mental State Examination; PA, physical activity.