Daily Mobility and MultipleExposures:Collecting and Using SpatialData in Health ResearchYan KestensMontreal University, So...
Context• Most health data contains limited spatial data• Yet society increasingly mobile, blurring of spatial andtemporal ...
Context• Most health data contains limited spatial data• Yet society increasingly mobile, blurring of spatial andtemporal ...
Context• Various methods to collect spatial data that can be used to tofeed epidemiological models and estimate multiple e...
ContextMobility surveysAllowed to compute activity space exposure tomultiple food sourcesEstimates of multiple exposures f...
ContextActivity spacequestionnairesSurveys regular destinationsVERITAS – Map-based interactive online questionnaireRECORD ...
ContextWearablesensorsWeb serverAcquisition serverOutputs /ApplicationsEnd usersGISAlgorithmsGSM towerSensorsCAPTUREPROCES...
ContextMobility surveysActivity spacequestionnairesWearablesensorsTime usesurveys
GPS – VERITAS spatial comparison• Sample of 89 RECORD Cohort Study participants from whichwe collected:– VERITAS activity ...
VERITAS dataTotal Home WorkOtherweeklyOther lessthanweeklyAverage 15,3 1,0 1,1 7,2 5,9Median 14,0 1,0 1,0 7,0 5,0Total of ...
GPS data0102030405060708090100PercentageofsurveydurationwithGPSfixesProportion of GPS survey duration withvalid GPS data5 ...
GPS data- GPS valid fix (raw)- GPS activity location (kernel density algorithm)- GPS confirmed location (prompted recall s...
020406080100120140HOME WORK OTHER WEEKLY OTHER LESS THANWEEKLYDistanceinmeters Shortest distance between VERITAS locationa...
050100150200250300350400450500HOME WORK OTHER WEEKLY OTHER LESS THANWEEKLYDistanceinmeters Shortest distance between VERIT...
020040060080010001200HOME WORK OTHER WEEKLY OTHER LESS THANWEEKLYDistanceinmeters Median shortest distance between VERITAS...
020406080100120140Shortest distance between GPS activitylocation and VERITAS location byVERITAS category(median value; n=1...
t0 t1 t2 t3 t5 t6 t7 t8 t9 t10 t11 t12 t135 5 5 5 10 5 5 5t14 t15 t1620 5 5Ellapsed time attributed to second of two conse...
1000250500100
1000250500100
0.000.100.200.300.400.500.600.700.800.901.00Within 100 m Within 250 m Within 500 m Within 1000mProportion of total survey ...
87%85%78%66%1000250500100
Convex hullsStandard deviation ellipse
VERITAS locations
CONVEX HULLAreaPerimeterForm factor
GPS tracksGPS activity location
Standard DeviationEllipse
020406080100120140160180200VERITAS ConvexHullGPS Convex Hull VERITAS 1 STDELLIPSEGPS 1STD ELLIPSEAreainkm2Convex hull and ...
0.000.100.200.300.400.500.600.700.800.901.00Overlap Veritas convexhullOverlap GPS convex hull Overlap Veritas ellipse Over...
9502468101214161820Unweighted Time weightedDistanceinkmDistance between ellipse geographic centers2.35 1.43
1. How close are GPS data to VERITAS location?Quite close!
2. How much time is spent around VERITASlocations?1. How close are GPS data to VERITAS location?Quite close!A lot!
2. How much time is spent around VERITASlocations?3. What is the spatial correspondencebetween the two point distributions...
CONCLUSIONSVERITAS an efficient tool to collect precise spatial information onregular destinationsGPS provides objective m...
CONCLUSIONSCAPTUREPROCESSINGUSAGE
CONCLUSIONSWeb serverAcquisition serverOutputs /ApplicationsEnd usersGISAlgorithmsGSM towerSensors
Thank you!SPHERE Lab .orgBenoit Thierry from SPHERELAB Julie Méline from RECORDAll the study participants!
ReferencesChaix, B., Kestens, Y., Perchoux, C., Karusisi, N., Merlo, J., & Labadi, K. (2012). Aninteractive mapping tool t...
Yan Kestens - Daily Mobility and Multiple Exposures:  Collecting and Using Spatial Data in Health Research
Yan Kestens - Daily Mobility and Multiple Exposures:  Collecting and Using Spatial Data in Health Research
Yan Kestens - Daily Mobility and Multiple Exposures:  Collecting and Using Spatial Data in Health Research
Yan Kestens - Daily Mobility and Multiple Exposures:  Collecting and Using Spatial Data in Health Research
Yan Kestens - Daily Mobility and Multiple Exposures:  Collecting and Using Spatial Data in Health Research
Yan Kestens - Daily Mobility and Multiple Exposures:  Collecting and Using Spatial Data in Health Research
Yan Kestens - Daily Mobility and Multiple Exposures:  Collecting and Using Spatial Data in Health Research
Yan Kestens - Daily Mobility and Multiple Exposures:  Collecting and Using Spatial Data in Health Research
Yan Kestens - Daily Mobility and Multiple Exposures:  Collecting and Using Spatial Data in Health Research
Yan Kestens - Daily Mobility and Multiple Exposures:  Collecting and Using Spatial Data in Health Research
Yan Kestens - Daily Mobility and Multiple Exposures:  Collecting and Using Spatial Data in Health Research
Yan Kestens - Daily Mobility and Multiple Exposures:  Collecting and Using Spatial Data in Health Research
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Yan Kestens - Daily Mobility and Multiple Exposures: Collecting and Using Spatial Data in Health Research

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Seminar given with Basile Chaix at London School of Hygiene and Tropical Medicine on Mobility and Exposure assessment for Epidemiological Modelling. Organisation: Steven Cummins & Daniel Lewis.

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Yan Kestens - Daily Mobility and Multiple Exposures: Collecting and Using Spatial Data in Health Research

  1. 1. Daily Mobility and MultipleExposures:Collecting and Using SpatialData in Health ResearchYan KestensMontreal University, Social and Preventive MedicineMontreal Hospital University Research Center (CRCHUM)SPHERE Lab .orgMAY 14th 2013
  2. 2. Context• Most health data contains limited spatial data• Yet society increasingly mobile, blurring of spatial andtemporal limits• Increasing interest in lifecycle / cumulative aspect• What methods to add spatial to epidemiology?
  3. 3. Context• Most health data contains limited spatial data• Yet society increasingly mobile, blurring of spatial andtemporal limits• Increasing interest in lifecycle / cumulative aspect• What methods to add spatial to epidemiology?
  4. 4. Context• Various methods to collect spatial data that can be used to tofeed epidemiological models and estimate multiple exposuresMobility surveysActivity spacequestionnairesWearablesensorsTime usesurveys
  5. 5. ContextMobility surveysAllowed to compute activity space exposure tomultiple food sourcesEstimates of multiple exposures for healthsurvey participantsAssociation between activity space exposureand BMI
  6. 6. ContextActivity spacequestionnairesSurveys regular destinationsVERITAS – Map-based interactive online questionnaireRECORD Cohort Study, Paris, AdultsBEANZ Study, Auckland, Adolescents & childrenERA-AGE Healthy Aging, Montreal, Paris, Luxembourg
  7. 7. ContextWearablesensorsWeb serverAcquisition serverOutputs /ApplicationsEnd usersGISAlgorithmsGSM towerSensorsCAPTUREPROCESSINGUSAGE
  8. 8. ContextMobility surveysActivity spacequestionnairesWearablesensorsTime usesurveys
  9. 9. GPS – VERITAS spatial comparison• Sample of 89 RECORD Cohort Study participants from whichwe collected:– VERITAS activity locations– 7-day continuous GPS monitoring– GPS-prompted recall survey data: validation of activitylocations, trips and transportation modes, nature ofactivities
  10. 10. VERITAS dataTotal Home WorkOtherweeklyOther lessthanweeklyAverage 15,3 1,0 1,1 7,2 5,9Median 14,0 1,0 1,0 7,0 5,0Total of 1,314 self-reported activity locations for 89 participantsHOME WORKPLACE OTHER DESTINATIONSWEEKLYLESS THANWEEKLYAverage number of reported locations
  11. 11. GPS data0102030405060708090100PercentageofsurveydurationwithGPSfixesProportion of GPS survey duration withvalid GPS data5 Days & 07:07:153 Days & 10:25:256 Days & 04:45:205 Days & 07:07:15Extraction of activity places from raw GPS data using kernel-based density algorithmSPHERELAB GPSARCTOOLBOX
  12. 12. GPS data- GPS valid fix (raw)- GPS activity location (kernel density algorithm)- GPS confirmed location (prompted recall survey)VERITAS locations- Self-reported activity locations identified on aninteractive online map (HOME, WORK, OTHER WEEKLY, LESSTHAN WEEKLY)DISTANCE BETWEENAND
  13. 13. 020406080100120140HOME WORK OTHER WEEKLY OTHER LESS THANWEEKLYDistanceinmeters Shortest distance between VERITAS locationand a GPS fix
  14. 14. 050100150200250300350400450500HOME WORK OTHER WEEKLY OTHER LESS THANWEEKLYDistanceinmeters Shortest distance between VERITAS locationand a GPS/algorithm detected activity location
  15. 15. 020040060080010001200HOME WORK OTHER WEEKLY OTHER LESS THANWEEKLYDistanceinmeters Median shortest distance between VERITAS locationand GPS-prompted recall location
  16. 16. 020406080100120140Shortest distance between GPS activitylocation and VERITAS location byVERITAS category(median value; n=1,314)
  17. 17. t0 t1 t2 t3 t5 t6 t7 t8 t9 t10 t11 t12 t135 5 5 5 10 5 5 5t14 t15 t1620 5 5Ellapsed time attributed to second of two consecutive GPS data fixesSum of individual fix durations = total survey duration1) Calculation of duration from GPS fixesx x xx2) Computation of proportion of survey duration spent within…100 m250 m500 m1000 m…of a VERITAS self-reported location
  18. 18. 1000250500100
  19. 19. 1000250500100
  20. 20. 0.000.100.200.300.400.500.600.700.800.901.00Within 100 m Within 250 m Within 500 m Within 1000mProportion of total survey time spent withinrange of VERITAS locations
  21. 21. 87%85%78%66%1000250500100
  22. 22. Convex hullsStandard deviation ellipse
  23. 23. VERITAS locations
  24. 24. CONVEX HULLAreaPerimeterForm factor
  25. 25. GPS tracksGPS activity location
  26. 26. Standard DeviationEllipse
  27. 27. 020406080100120140160180200VERITAS ConvexHullGPS Convex Hull VERITAS 1 STDELLIPSEGPS 1STD ELLIPSEAreainkm2Convex hull and 1 STD ellipse size3016323 23
  28. 28. 0.000.100.200.300.400.500.600.700.800.901.00Overlap Veritas convexhullOverlap GPS convex hull Overlap Veritas ellipse Overlap GPS ellipseProportionofoverlapSpatial overlap (Convex hull, Standarddeviation ellipse)301634257951195
  29. 29. 9502468101214161820Unweighted Time weightedDistanceinkmDistance between ellipse geographic centers2.35 1.43
  30. 30. 1. How close are GPS data to VERITAS location?Quite close!
  31. 31. 2. How much time is spent around VERITASlocations?1. How close are GPS data to VERITAS location?Quite close!A lot!
  32. 32. 2. How much time is spent around VERITASlocations?3. What is the spatial correspondencebetween the two point distributions?1. How close are GPS data to VERITAS location?Quite close!A lot!All depends!
  33. 33. CONCLUSIONSVERITAS an efficient tool to collect precise spatial information onregular destinationsGPS provides objective measures of mobility, can prompt recallsurveysIncreasing use of embedded GPS sensors, health surveys andremote patient monitoring
  34. 34. CONCLUSIONSCAPTUREPROCESSINGUSAGE
  35. 35. CONCLUSIONSWeb serverAcquisition serverOutputs /ApplicationsEnd usersGISAlgorithmsGSM towerSensors
  36. 36. Thank you!SPHERE Lab .orgBenoit Thierry from SPHERELAB Julie Méline from RECORDAll the study participants!
  37. 37. ReferencesChaix, B., Kestens, Y., Perchoux, C., Karusisi, N., Merlo, J., & Labadi, K. (2012). Aninteractive mapping tool to assess individual mobility patterns in neighborhoodstudies. Am J Prev Med, 43(4), 440-450. doi: 10.1016/j.amepre.2012.06.026Chaix, B., Méline, J., Duncan, S., Merrien, C., Karusisi, N., Perchoux, C., Lewin, A., Labadi, K., Kestens, Y. (2013). GPS tracking in neighborhood and health studies: A stepforward for environmental exposure assessment, a step backward for causalinference? Health & Place, 21(0), 46-51.Kestens, Y., Lebel, A., Chaix, B., Clary, C., Daniel, M., Pampalon, R., . . . SV, P. S. (2012).Association between activity space exposure to food establishments and individualrisk of overweight. PLoS One, 7(8)Kestens, Y., Lebel, A., Daniel, M., Theriault, M., & Pampalon, R. (2010). Usingexperienced activity spaces to measure foodscape exposure. Health Place, 16(6),Thierry, B., Chaix, B., & Kestens, Y. (2013). Detecting activity locations from raw GPSdata: a novel kernel-based algorithm. Int J Health Geogr, 12(1), 14. doi: 10.1186/1476-072X-12-14Perchoux, C., Chaix, B., Cummins, S., & Kestens, Y. (2013). Conceptualization andmeasurement of environmental exposure in epidemiology: Accounting for activityspace related to daily mobility. Health Place, 21C, 86-93. doi:10.1016/j.healthplace.2013.01.005

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