Spatial Epidemiology and Obesity Risk Phil Hurvitz Urban Form Lab College of Architecture & Urban Planning University of Washington Slide 1 (of 20)

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. Slide 2 (of 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 Slide 3 (of 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 Slide 4 (of 20)

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. Slide 5 (of 20)

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

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 Slide 6 (of 20)

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 Slide 7 (of 20)

GIS combines coordinate (map) and attribute (tabular/statistical) data Slide 8 (of 20)

I told myself I’d never do this The world’s first GIS geek? Dr. John Snow Slide 9 (of 20)

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?” Slide 10 (of 20)

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 Slide 11 (of 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 Slide 12 (of 20)

Factors in obesity risk Race SES Location/Exposure ↓ PA Genetics O ↑ Calories Slide 13 (of 20)

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 + Slide 14 (of 20)

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? Slide 15 (of 20)

The Big Picture We can intervene in these arenas: Social/Community Institutional/Policy Built Environment Slide 16 (of 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 Slide 17 (of 20)

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 Slide 18 (of 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 Slide 19 (of 20)

Questions? phurvitz@u.washington.edu http://gis.washington.edu/phurvitz Slide 20 (of 20)