1. Spatial Epidemiology and Obesity Risk
Phil Hurvitz Urban Form Lab College of Architecture & Urban Planning University of Washington
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2. Location and Health
“…investigating how places are related to health will require learning to characterize places as well as we have learned to characterize the biology and behavior of people” Diez Roux AV. Invited commentary: places, people, and health. Am J Epidemiol 2002;155(6):516-8.
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3. Overview The spatial epidemiology approach, definitions, GIS
Factors in obesity risk
How GIS helps clarify spatial nature of risk factors
Current research in Urban Form Lab
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4. Overview The spatial epidemiology approach, definitions, GIS
Factors in obesity risk
How GIS helps clarify spatial nature of risk factors
Current research in Urban Form Lab
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5. Spatial epidemiology definition
“Spatial epidemiology is the description and analysis of geographic variations in disease with respect to demographic, environmental, behavioral, socioeconomic, genetic, and infectious risk factors.”
Elliott P, Wartenberg D. Spatial epidemiology: current approaches and future challenges. Environ Health Perspect. 2004;112:998–1006.
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6. Spatial Epidemiology Approach
Traditional epidemiology studies the causes and spread of disease in populations
As strange as it may seem, traditional epidemiology frequently ignores spatial aspects of disease
Spatial epidemiology explicitly addresses the spatial factors that mediate or moderate disease

7. What is GIS? A computer-based method for of spatially referenced data
Capture,
Storage,
Manipulation,
Analysis, and
Display
of spatially referenced data
Standard GIS definition
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8. 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
Disease occurrence
Expounded a bit
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9. GIS combines coordinate (map) and attribute (tabular/statistical) data
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10. I told myself I’d never do this
The world’s first GIS geek?
Dr. John Snow
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11. Importance of Snow’s work
Knowledge of spatial factors led to the conclusion that a local environmental effect was responsible for the cholera outbreak
A simple idea led to breakthroughs in the identification and control of exposure to disease causing agents
Knowing where illness occurs is essential
Begs the question: “Why is it taking so long to use spatial methods in Public Health?”
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12. The Big Picture
Spatial information science allows us to understand the spatial phenomena and processes related to disease
Knowledge of the inherently spatial patterns and processes of risk factors and the structure & function of environments will be critical in dealing with the obesity pandemic
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13. Overview The spatial epidemiology approach, definitions, GIS
Factors in obesity risk
How GIS helps clarify spatial nature of risk factors
Current research in Urban Form Lab
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14. Factors in obesity risk
Race
SES
Location/Exposure
↓ PA
Genetics O
↑ Calories
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15. Conceptual Framework for Social Ecologic Model
Social ecologic model considers impacts of environment (institutional, physical, social, etc.) on behavior. (Stokols, 1992; Sallis and Owen 1997)
Inner personal environment
Outer environments
Person (behavior)
Intervention – behavior change/modification
Personal/individual factors = =
Social/community environmental factors
Institutional/policy environmental factors
Built environmental factors +
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16. The Built Environment Matters
“We shape our buildings; thereafter they shape us.” Sir Winston Churchill
Income and built environment
Non-motorized transport built environment
Confounder in studies of behavior and the built environment: Self-selection and causation
Do people move to walkable neighborhoods and then start walking, or do walkers search out walkable neighborhoods?
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17. The Big Picture We can intervene in these arenas: Social/Community
Institutional/Policy
Built Environment
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18. Overview The spatial epidemiology approach, definitions, GIS
Factors in obesity risk
How GIS helps clarify spatial nature of risk factors
Current research in Urban Form Lab
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19. Why is GIS Important in Epidemiology?
Epidemiology and public health focus on population-wide effects
Population-wide effects can only be ascertained from individual-level measurements
GIS allows the measurement of individual characteristics within an explicitly spatial context
GIS allows the quantification of environment at a high level of detail (census → zip → parcel)
If location is an important factor in a public health issue, GIS should (must?) be incorporated as a data management and analysis tool
What does GIS have to offer epidemiology, in the most generic sense
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20. Overview The spatial epidemiology approach, definitions GIS
Factors in obesity risk
How GIS helps clarify spatial nature of risk factors
Current research in Urban Form Lab
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21. Questions? phurvitz@u.washington.edu
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