Background: Physical disability is common though not inevitable in older age and has direct bearing on a person’s ability to perform activities essential for self-care and independent living. Air pollution appears to increase the risk of several chronic diseases that contribute to the progression of disability.
Objective: We evaluated long-term exposure to traffic-related air pollution (TRAP) in relation to progression in physical disability.
Methods: We conducted our investigation within the Chicago Health and Aging Project. We measured participants’ exposures to TRAP using two surrogates: residential proximity to major roads (1993 onwards) and ambient concentrations of oxides of nitrogen (NOX; 1999 onwards), predicted via a geographic information systems-based spatiotemporal smoothing model (cross-validation R2 = 0.87) that incorporated community-based monitoring and resolved intraurban exposure gradients at a spatial scale of tens of meters. Participants’ lower-extremity physical ability was assessed every 3 years (1993–2012) via tandem stand, chair stand, and timed walking speed.
Results: In multivariable-adjusted analyses (n = 5,708), higher long-term NOX exposure was associated with significantly faster progression in disability. Compared with the 5-year decline in physical ability score among participants in the lowest quartile of NOX exposure, decline among those in the highest exposure quartile was 1.14 units greater (95% confidence interval [CI]: –1.86, –0.42), equivalent to 3 additional years of decline among those in the lowest exposure quartile. The association was linear across the continuum of NOX exposure: per 10-ppb increment in exposure, the 5-year decline in physical ability score was 0.87 unit greater (95% CI: –1.35, –0.39). Proximity to a major road was not associated with disability progression (n = 9,994).
Conclusions: These data join a growing body of evidence suggesting that TRAP exposures may accelerate aging-related declines in health.
1Rush Institute for Healthy Aging, Department of Internal Medicine, Rush University Medical Center, Chicago, Illinois, USA; 2Department of Environmental and Occupational Health Sciences, and 3Department of Epidemiology, University of Washington School of Public Health, Seattle, Washington, USA; 4Department of Medicine, University of Washington, Seattle, Washington, USA; 5Department of Biostatistics, University of Washington School of Public Health, Seattle, Washington, USA; 6Department of Community and Environmental Health, College of Health Sciences, Boise State University, Boise, Idaho, USA; 7Maryland Institute of Applied Environmental Health, School of Public Heath, University of Maryland, College Park, Maryland, USA; 8Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
Recommended Citation:
Jennifer Weuve,1 Joel D. Kaufman,2,et al. Exposure to Traffic-Related Air Pollution in Relation to Progression in Physical Disability among Older Adults[J]. Environmental Health Perspectives,2016-01-01,Volume 124(Issue 7):1000