title: Health impacts of the built environment: within-urban variability in physical inactivity, air pollution, and ischemic heart disease mortality.
abstract: BACKGROUND
  Physical inactivity and exposure to air pollution are important risk factors for death and disease globally. The built environment may influence exposures to these risk factors in different ways and thus differentially affect the health of urban populations.
  
  
  OBJECTIVE
  We investigated the built environment's association with air pollution and physical inactivity, and estimated attributable health risks.
  
  
  METHODS
  We used a regional travel survey to estimate within-urban variability in physical inactivity and home-based air pollution exposure [particulate matter with aerodynamic diameter ≤ 2.5 μm (PM2.5), nitrogen oxides (NOx), and ozone (O3)] for 30,007 individuals in southern California. We then estimated the resulting risk for ischemic heart disease (IHD) using literature-derived dose-response values. Using a cross-sectional approach, we compared estimated IHD mortality risks among neighborhoods based on "walkability" scores.
  
  
  RESULTS
  The proportion of physically active individuals was higher in high- versus low-walkability neighborhoods (24.9% vs. 12.5%); however, only a small proportion of the population was physically active, and between-neighborhood variability in estimated IHD mortality attributable to physical inactivity was modest (7 fewer IHD deaths/100,000/year in high- vs. low-walkability neighborhoods). Between-neighborhood differences in estimated IHD mortality from air pollution were comparable in magnitude (9 more IHD deaths/100,000/year for PM2.5 and 3 fewer IHD deaths for O3 in high- vs. low-walkability neighborhoods), suggesting that population health benefits from increased physical activity in high-walkability neighborhoods may be offset by adverse effects of air pollution exposure.
  
  
  CONCLUSIONS
  Currently, planning efforts mainly focus on increasing physical activity through neighborhood design. Our results suggest that differences in population health impacts among neighborhoods are similar in magnitude for air pollution and physical activity. Thus, physical activity and exposure to air pollution are critical aspects of planning for cleaner, health-promoting cities.
authors: Department of Civil Engineering, University of Minnesota, Minneapolis, Minnesota, USA.
authors: Steve
authors: S
authors: Hankey
authors: Julian D
authors: JD
authors: Marshall
authors: Michael
authors: M
authors: Brauer
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D016902:Air Pollution, Indoor / Q000032:analysis; D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D017202:Myocardial Ischemia / Q000139:chemically induced / Q000453:epidemiology* / Q000401:mortality*; D009589:Nitrogen Oxides / Q000032:analysis / Q000633:toxicity; D010126:Ozone / Q000032:analysis / Q000633:toxicity; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity; D012111:Residence Characteristics; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D013997:Time Factors; D014504:Urban Health; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D009589:Nitrogen Oxides; D052638:Particulate Matter; D010126:Ozone