Measuring Physical Activity and Location in Real Time

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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 Unpublished data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 Activityand Location in Real TimePhil HurvitzUniversity of WashingtonCollege of Architecture and Urban PlanningUrban Form Labgis.washington.edu/phurvitzMEBI 591B Public Health Informatics Seminar2007.05.04Confidentiality
  • Unpublished data
  • Please do not distribute
  • Slide 2 (of 45)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)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)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)Introduction/Background: Obesity TrendsSlide 6 (of 45)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)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)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)Introduction to GIS: What is GIS?
  • A computer-based method for
  • Capture,
  • Storage,
  • Manipulation,
  • Analysis, and
  • Display
  • of spatially referenced dataSlide 10 (of 45)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)Introduction to GIS: Data FrameworkGIS combines coordinate (map) and attribute (tabular/statistical) dataSlide 12 (of 45)Introduction to GIS: Coordinate FrameworkSlide 13 (of 45)Introduction to GIS: Address Location
  • GIS can match address records to spatial location
  • Slide 14 (of 45)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)Introduction to GIS: Risk or Exposure EstimationMiranda, M. L. and D. C. Dolinoy. 2005. Neurotoxicology. 26(2). 223-228Slide 16 (of 45)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 spaceSlide 17 (of 45)Introduction to GIS: Risk Surface Estimation
  • Fast food restaurant KDE
  • Slide 18 (of 45)Introduction to GIS: Risk Estimation
  • Is there a relationship between fast food density and obesity?
  • p-value = 0.155Slide 19 (of 45)Introduction to GIS: Risk Surface Estimation
  • Kriging (geostatistical analysis)
  • sig. relationshipbetween Pb insoil and blood♀ eating homegrownvegetablesHellstrom, L., L. Jarup, B. Persson and O. Axelson. 2004. J Expo Anal Environ Epidemiol. 14(5). 416-23.Slide 20 (of 45)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)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)Measuring Physical Activity: Benefits & DrawbacksSlide 23 (of 45)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)Measuring Physical Activity: New Generation Devices
  • IDEAA: recognizable activities
  • Slide 25 (of 45)Measuring Physical Activity: New Generation Devices
  • IDEAA: categorized activities by time
  • Slide 26 (of 45)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)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)Classified Activity (by HMM)Walking Riding Riding Walking Riding a Driving SittingStandingWalkingJoggingdown elevator elevator up stairsbicyclecarstairsdownup89.8%38.5%0.5%0.4%33.4%Sitting10.1%50.8%1.4%Standing0.1%7.4%97.7%5.2%2.5%Walking100.0%JoggingPrecision94.8%Walking up stairsLabeled Activities0.5%97.5%Walking down stairs3.3%99.6%Riding a bicycle66.6%Driving car100.0%Riding elevator down100.0%Riding elevator upMeasuring Physical Activity: New Generation Devices
  • Multi-Sensor Board Activity Classifier (overall accuracy > 95%)
  • Validated against videography
  • Slide 29 (of 45)Measuring Physical Activity: New Generation Devices
  • Multi-Sensor Board Classification of Activity90-minute interval
  • Slide 30 (of 45)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)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)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)Measuring the Built Environment: A GIS Based ApproachSlide 34 (of 45)Measuring the Built Environment: A GIS Based Approach
  • GIS analysis results for each location
  • buffer(count)measuresproximitymeasuresSlide 35 (of 45)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)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)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 pointsSlide 38 (of 45)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)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)RRF Funded Research: Results from Pilot & Feasibility Study
  • Sample demographics
  • Slide 41 (of 45)RRF Funded Research: Results from Pilot & Feasibility Study
  • MSB activity & location
  • Slide 42 (of 45)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 schemep=0.05, Fisher’s exact test Slide 43 (of 45)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)Suggestions/QuestionsPhil Hurvitzphurvitz@u.washington.edugis.washington.edu/phurvitzgis.washington.edu/phurvitz/msbSlide 45 (of 45)
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