Purpose This study aimed to examine the comparability of the ActiGraph 7164 and wGT3X-BT wear time, count-based estimates, and average time per day in physical activity of different intensities. Methods We studied 87 Coronary Artery Risk Development in Young Adults (CARDIA) participants 48-60 yr of age who simultaneously wore the 7164 and wGT3X-BT accelerometers at the waist in 2015-2016, with wear time of ≥4 of 7 d, ≥10 h·d-1 for both monitors. Freedson cutpoints (counts per minute) were used to define sedentary (<100), light (100-1951), moderate (1952-5724), and vigorous activity (≥5725). Agreement was evaluated using paired-difference tests, intraclass correlation coefficients, and Bland-Altman plots. Given systematic differences in count-based estimates between monitors, a calibration formula applied to the wGT3X-BT values was obtained by linear regression. Results Total detected wear time minutes per day was nearly identical between the 7164 and the wGT3X-BT (881.5 ± 70.9 vs 880.3 ± 78.1, P = 0.72). The wGT3X-BT values were calibrated to the 7164 values by dividing counts by 1.088. After calibration, no differences were observed between the 7164 and the wGT3X-BT in total counts per day (310,184 ± 129,189 vs 307,085 ± 135,362, P = 0.48), average counts per min per day (349.5 ± 139.5 vs 346.5 ± 147.2, P = 0.54), sedentary (513.2 ± 93.6 vs 509.6 ± 98.6, P = 0.23), light (335.3 ± 81.5 vs 338.7 ± 81.1, P = 0.22), moderate (31.0 ± 21.9 vs 30.3 ± 23.4, P = 0.31), or moderate-to-vigorous minutes per day (33.1 ± 24.6 vs 32.0 ± 26.0, P = 0.13). A significant difference was observed for vigorous minutes per day (0.2 ± 1.0 vs 0.0 ± 0.3, P < 0.01); however, the absolute difference was marginal. Intraclass correlation coefficients showed excellent agreement for all measures (0.95-0.99). Conclusions After applying a calibration formula, the 7164 and wGT3X-BT were comparable for total wear time, count-based estimates, and average minutes per day in sedentary, light, moderate, and moderate-to-vigorous activity. Findings illustrate a novel methodological approach to facilitate accelerometer data harmonization.
Bibliographical noteFunding Information:
The Coronary Artery Risk Development in Young Adults Study is supported by contracts HHSN268201300025C, HHSN268201300026C, HHSN268201300027C, HHSN268201300028C, HHSN268201300029C, and HHSN268200900041C from the National Heart, Lung, and Blood Institute (NHLBI), the Intramural Research Program of the National Institute on Aging, and an intra-agency agreement between the National Institute on Aging and the NHLBI (AG0005). Accelerometer data collection was supported by grants R01 HL078972 and R56 HL125423 from the NHLBI. K. M. W. was supported by T32 HL007779 from the NHLBI
- ACTIGRAPH 7164
- ACTIGRAPH WGT3X-BT
- CORONARY RISK DEVELOPMENT IN YOUNG ADULTS