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Measuring Physical Activity and Location in Real Time

Measuring Physical Activity and Location in Real Time. Phil Hurvitz University of Washington College of Architecture and Urban Planning Urban Form Lab gis.washington.edu/phurvitz MEBI 591B Public Health Informatics Seminar 2007.05.04. Confidentiality. Unpublished data

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Measuring Physical Activity and Location in Real Time

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  1. Measuring Physical Activityand Location in Real Time Phil Hurvitz University of Washington College of Architecture and Urban Planning Urban Form Lab gis.washington.edu/phurvitz MEBI 591B Public Health Informatics Seminar 2007.05.04

  2. Confidentiality • Unpublished data • Please do not distribute Slide 2 (of 45)

  3. Overview • Introduction/Background/Relevance • What is GIS, and what is its role in Public Health? • Measuring Physical Activity • Measuring the Built Environment • UW-RRF Funded Research: Validation of New Technologies and Methodologies for Measuring Physical Activity and Location in Real Time-Space • Analysis Plan • Suggestions/Questions Slide 3 (of 45)

  4. Overview • Introduction/Background • What is GIS, and what is its role in Public Health? • Measuring Physical Activity • Measuring the Built Environment • UW-RRF Funded Research: Validation of New Technologies and Methodologies for Measuring Physical Activity and Location in Real Time-Space • Analysis Plan • Suggestions/Questions Slide 4 (of 45)

  5. Source: CDC BRFSS (http://apps.nccd.cdc.gov/brfss/Trends/trendchart.asp) Introduction/Background: Obesity • Obesity threatens personal health and may bankrupt the US health care system • Obesity incidence has increased dramatically over the last 20 years Slide 5 (of 45)

  6. Introduction/Background: Obesity Trends Slide 6 (of 45)

  7. Introduction/Background: Diet & Exercise • Nutrition guidelines: “Eat more grains, fruits, vegetables…” • Health care system says, “Eat less, exercise more.” • Technology and food provides choices that are not conducive to healthy lifestyles Slide 7 (of 45)

  8. Introduction/Background: Physical Activity • Increasing physical activity is important for maintaining or decreasing weight, and for general health • The built environment can either promote or hinder physical activity, e.g., • Presence/absence of sidewalks • Presence/absence of utilitarian destinations (e.g., restaurants, retail stores, restaurants, banks) • Research Question: How does physical activity vary with different compositions and configurations of environment? Slide 8 (of 45)

  9. Overview • Introduction/Background • What is GIS, and what is its role in Public Health? • Measuring Physical Activity • Measuring the Built Environment • UW-RRF Funded Research: Validation of New Technologies and Methodologies for Measuring Physical Activity and Location in Real Time-Space • Analysis Plan • Suggestions/Questions Slide 9 (of 45)

  10. Introduction to GIS: What is GIS? • A computer-based method for • Capture, • Storage, • Manipulation, • Analysis, and • Display of spatially referenced data Slide 10 (of 45)

  11. Introduction to GIS: What is GIS? • Any object or phenomenon that is or can be placed on a map can be stored, managed, and analyzed in a GIS. • Built environment features (streets, buildings, bus routes, restaurants, schools) • Households (address points, tax-lot polygons) • Individuals (points or travel lines/polygons) • Ground surface elevation or slope • Movement of objects through time and/or space • Demographics, socioeconomics • Patient residence, work, and school locations • Exposure or risk estimation • Disease occurrence Slide 11 (of 45)

  12. Introduction to GIS: Data Framework GIS combines coordinate (map) and attribute (tabular/statistical) data Slide 12 (of 45)

  13. Introduction to GIS: Coordinate Framework Slide 13 (of 45)

  14. Introduction to GIS: Address Location • GIS can match address records to spatial location Slide 14 (of 45)

  15. Introduction to GIS: Analysis • Analytical techniques (a very simple list) • Spatial aggregation • Disease rates per census or zip code area • Buffering • How many pedestrian-auto collisions within 1 mile of schools? • Overlay/Proximity analysis • How much of each census block group is affected by a toxic aerosol plume? • How many parcels of each type of land use are within ½ mile of all walking locations visited within a day? • Surface generation, interpolation • Trend or density surfaces • Kriging Slide 15 (of 45)

  16. Introduction to GIS: Risk or Exposure Estimation Miranda, M. L. and D. C. Dolinoy. 2005. Neurotoxicology. 26(2). 223-228 Slide 16 (of 45)

  17. Introduction to GIS: Risk Surface Estimation • Kernel density estimator (KDE) creates a Gaussian surface for each individual point location and sums each individual surface across XY space Slide 17 (of 45)

  18. Introduction to GIS: Risk Surface Estimation • Fast food restaurant KDE Slide 18 (of 45)

  19. Introduction to GIS: Risk Estimation • Is there a relationship between fast food density and obesity? p-value = 0.155 Slide 19 (of 45)

  20. Introduction to GIS: Risk Surface Estimation • Kriging (geostatistical analysis) sig. relationshipbetween Pb insoil and blood♀ eating homegrownvegetables Hellstrom, L., L. Jarup, B. Persson and O. Axelson. 2004. J Expo Anal Environ Epidemiol. 14(5). 416-23. Slide 20 (of 45)

  21. Overview • Introduction/Background • What is GIS, and what is its role in Public Health? • Measuring Physical Activity • Measuring the Built Environment • UW-RRF Funded Research: Validation of New Technologies and Methodologies for Measuring Physical Activity and Location in Real Time-Space • Analysis Plan • Suggestions/Questions Slide 21 (of 45)

  22. Measuring Physical Activity: How? • Subjective • Observation • Self-Report • Stanford 7-Day Activity Survey • International Physical Activity Questionnaire (IPAQ) • Travel Diaries • Objective • Pedometers • Accelerometers • New Generation Devices Slide 22 (of 45)

  23. Measuring Physical Activity: Benefits & Drawbacks Slide 23 (of 45)

  24. Measuring Physical Activity: New Generation Devices • Intelligent Device for Energy Expenditure and Activity (IDEAA) • sensors attached to skin (cumbersome) • relative accelerometry of different body parts • no locational capability • no external environmental cues • $4,000 per unit Slide 24 (of 45)

  25. Measuring Physical Activity: New Generation Devices • IDEAA: recognizable activities Slide 25 (of 45)

  26. Measuring Physical Activity: New Generation Devices • IDEAA: categorized activities by time Slide 26 (of 45)

  27. Measuring Physical Activity: New Generation Devices • Multi-Sensor Board • UW/Intel invention, recent development • single sensing unit with data logger (smart phone) • easily worn • measures multiple environmental data streams • obtains XY locational data • estimated $100 per unit costin large manufacturing run Slide 27 (of 45)

  28. Measuring Physical Activity: New Generation Devices • Multi-Sensor Board • On-board sensors: • accelerometry • audio • IR / visible light • high-frequency light • barometric pressure • humidity, temperature • geophysical location (from GPS) • Multivariate data stream can be interpreted as a number of common activities using Hidden Markov Model with Decision Stumps classifiers • Used in ECOR Pilot & Feasibility Study Slide 28 (of 45)

  29. Classified Activity (by HMM) Walking Riding Riding Walking Riding a Driving Sitting Standing Walking Jogging down elevator elevator up stairs bicycle car stairs down up 89.8% 38.5% 0.5% 0.4% 33.4% Sitting 10.1% 50.8% 1.4% Standing 0.1% 7.4% 97.7% 5.2% 2.5% Walking 100.0% Jogging Precision 94.8% Walking up stairs Labeled Activities 0.5% 97.5% Walking down stairs 3.3% 99.6% Riding a bicycle 66.6% Driving car 100.0% Riding elevator down 100.0% Riding elevator up Measuring Physical Activity: New Generation Devices • Multi-Sensor Board Activity Classifier (overall accuracy > 95%) • Validated against videography Slide 29 (of 45)

  30. Measuring Physical Activity: New Generation Devices • Multi-Sensor Board Classification of Activity90-minute interval Slide 30 (of 45)

  31. Overview • Introduction/Background • What is GIS, and what is its role in Public Health? • Measuring Physical Activity • Measuring the Built Environment • UW-RRF Funded Research: Validation of New Technologies and Methodologies for Measuring Physical Activity and Location in Real Time-Space • Analysis Plan • Suggestions/Questions Slide 31 (of 45)

  32. Measuring the Built Environment: What and Where? • What to Measure? • Based on Research Question(s) • GIS Data Sources • Point Locations • Buffer Measures • Proximity Measures • Where to Measure? • Home-centered • Frank et al. 2005 • Moudon et al. 2005 • Where does activity take place in real time? Slide 32 (of 45)

  33. Measuring the Built Environment: A GIS Based Approach • Point-centered Analysis of Location • Any number of different data sets can be quantified • Enumeration & relative proportion of different land uses • Parcel density • Street-block size • Total length of sidewalk • Number of intersections, lighted crosswalks • Area and count of parks • Distance to different built environment features • We should quantify & analyze all locations that are experienced during the day, not only the home location • Work & school environments may be key determinants of physical activity Slide 33 (of 45)

  34. Measuring the Built Environment: A GIS Based Approach Slide 34 (of 45)

  35. Measuring the Built Environment: A GIS Based Approach • GIS analysis results for each location buffer(count)measures proximitymeasures Slide 35 (of 45)

  36. Overview • Introduction/Background • What is GIS, and what is its role in Public Health? • Measuring Physical Activity • Measuring the Built Environment • UW-RRF Funded Research: Validation of New Technologies and Methodologies for Measuring Physical Activity and Location in Real Time-Space • Analysis Plan • Suggestions/Questions Slide 36 (of 45)

  37. RRF Funded Research • Validation of New Technologies and Methodologies for Measuring Physical Activity and Location in Real Time-Space • MSB to capture • Activity type • Location • Walkable-Bikeable Communities GIS Software • Quantifying & analyzing the Built Environment Slide 37 (of 45)

  38. RRF Funded Research: Analysis Plan • MSB activity & location • Validity tests against diary (real-time location & activity), IPAQ (self-reported physical activity summary) • WBC location analysis of Built Environment Data overload? 15 h * 60 min/h * 60 s/min * 7 d * 40 subjects = 15,120,000 data points Slide 38 (of 45)

  39. RRF Funded Research: Analysis Plan • Sampling strategy for data reduction without loss of variability 10% sample → 1.5 million data points (time or distance?) Slide 39 (of 45)

  40. RRF Funded Research: Analysis Plan • This will be the first study to measure objectively • both physical activity types and Built Environment in a real-time, real-world setting with free-roaming individuals • Statistical associations? • Activity types/intensities & Built Environment types? • What do we gain if a pattern is discovered? • Policy recommendations • Quantitative urban design guidelines • A new “gold standard” for measurement of physical activity in real-time Slide 40 (of 45)

  41. RRF Funded Research: Results from Pilot & Feasibility Study • Sample demographics Slide 41 (of 45)

  42. RRF Funded Research: Results from Pilot & Feasibility Study • MSB activity & location Slide 42 (of 45)

  43. RRF Funded Research: Results from Pilot & Feasibility Study • Automatic classification vs. self-report (42 diary entries) * “None” indicates the classifier was not able to classify a given activity † “Shopping” was a user-added activity type that had no match in the automatic classification scheme p=0.05, Fisher’s exact test Slide 43 (of 45)

  44. Overview • Introduction/Background • What is GIS, and what is its role in Public Health? • Measuring Physical Activity • Measuring the Built Environment • UW-RRF Funded Research: Validation of New Technologies and Methodologies for Measuring Physical Activity and Location in Real Time-Space • Analysis Plan • Suggestions/Questions Slide 44 (of 45)

  45. Suggestions/Questions Phil Hurvitz phurvitz@u.washington.edu gis.washington.edu/phurvitz gis.washington.edu/phurvitz/msb Slide 45 (of 45)

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