engleski

A Pilot Study to Collect Time-Location-Activity Data Using a Mass Market Smartphone App and Fitness Tracking Device

It is now possible for the general public to record their location and activity using their phones and wearable fitness trackers. This provides a potentially widespread and less expensive method of collecting time-location-activity data. As part of the HEALS project (www.heals-eu.eu ), funded by the European Union 7th Framework Programme (EU FP7), a pilot study to investigate the potential use of smart consumer products in measuring personal time-location-activity information for exposure studies was conducted. Four participants in 7 cities across Europe (Athens, Edinburgh, Kozani, Stuttgart, Thessaloniki, Zagreb, Zeist/Utrecht) wore a Fitbit Flex and used the Moves app on their smartphone for approximately 1 week. The participants also wore a GPS unit, Actigraph, and filled out a time-activity log on paper for the same time period. The Moves smartphone app and the Fitbit Flex fitness tracker were compared to a GPS and paper time-activity diaries for time-location, and an Actigraph for activity. Fitbit and Actigraph steps per minute were compared using Lin’s Concordance Coefficient, and Bland Altman plots. Analyses for a subset of the participants show a moderate concordance (0.78, 95th CI = 0.77, 0.79). Scatter plots show that the concordance is highest for high intensity activity in terms of steps per minute, with a wide spread for low and moderate intensity activity. The Fitbit tended to overestimate Actigraph steps. The mean difference between Fitbit and Actigraph was -10.9 steps/min (95th CI = -11.5, -10.4), with 7% of the total points (n=6414) outside the limits of agreement (-55, 35 steps/min). Correspondence of Moves with GPS and paper log differed between people, with a 69-95% correspondence with GPS and 78-93% with the paper log. Further analyses of the complete dataset will provide information as to the potential to use Fitbit and Moves as new means of recording time-location-activity information for exposure studies.

activity patterns; exposure factors; sensor technology

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