Exposure to Traffic-Related Air Pollution in Relation to Progression in Physical Disability among Ol
Exposure to Traffic-Related Air Pollution in Relation to Progression in Physical Disability among Older Adults
http://ehp.niehs.nih.gov/15-10089/
http://ehp.niehs.nih.gov/wp-content/uploads/advpub/2016/3/ehp.1510089.acco.pdf
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: Evaluate 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–) and ambient concentrations of oxides of nitrogen (NOX; 1999–), predicted via a geographic information systems-based spatiotemporal smoothing model (cross-validation R2=0.87) which incorporated community-based monitoring and resolves intra-urban 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=5708), higher long-term NOX exposure was associated with significantly faster progression in disability. Compared with 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 to -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 to -0.39). Proximity to major road was not associated with disability progression (N=9994).
Conclusions: These data join a growing body of evidence suggesting that TRAP exposures may accelerate aging-related declines in health.
