Integrating Mobility and Time-Activity Patterns in Assessing Environmental Exposures During Pregnancy and Early Postpartum

Authors: Li Yi*, University of Southern California, Yan Xu, University of Southern California, Sydney O'Connor, University of Southern California, Jane Cabison, University of Southern California, Daniel Chu, University of Southern California, Thomas Chavez, University of Southern California, Tyler Mason, University of Southern California, Theresa Bastain, University of Southern California, Carrie Breton, University of Southern California, Genevieve Dunton, University of Southern California, John Wilson, University of Southern California, Rima Habre, University of Southern California
Topics: Spatial Analysis & Modeling, Geographic Information Science and Systems, Medical and Health Geography
Keywords: GPS, time-activity pattern, mobility pattern, environment exposure, maternal health
Session Type: Virtual Paper
Day: 4/10/2021
Start / End Time: 11:10 AM / 12:25 PM
Room: Virtual 8
Presentation File: No File Uploaded


Background: Maternal mobility and time-activity patterns are important determinants of personal physical environment exposure and can influence their metabolic health during pre- and post-partum period. Low income, Hispanic women living in Los Angeles, CA, experience disproportionately higher adverse environmental exposures (e.g., lack of greenspaces), yet most studies assess these exposures within residential neighborhoods without considering daily mobility patterns and dynamic exposures encountered in actual activity spaces.

Methods: We conducted 4-day continuous geolocation monitoring in 63 pregnant, Hispanic women enrolled in the MADRES cohort during their 1st and 3rd trimester and 4-6 months postpartum using our madresGPS app. We performed stay/trip detection through Kernel Density Estimation (KDE) algorithms. We derived time-activity patterns by classifying stays into home or non-home and trips into pedestrian and vehicular. We lastly calculated the contribution of these time-activity parameters to overall dynamic exposure (e.g., greenness).

Results: Mean (std) daily time spent at home, non-home, and in trips was 1198 (278), 138 (191), and 88.1 (126) mins, respectively (n=552 person-days). Preliminary analyses showed a decreasing trend in time spent at non-home contexts and an increasing trend in time spent at home and in trips during pre- and post-partum period, which indicated reduced mobility. Ongoing analyses are estimating time spent at pedestrian- and vehicular-based trips and their contribution to 24-hour dynamic exposure to greenness.

Conclusions: Our findings highlight the large discrepancy in maternal mobility estimates when considering actual time-activity patterns opposed to the typical stationary, residential-only assumptions, with important implications for exposure measurement error in pregnancy studies.

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