Journal Article

Traffic-Related Air Pollution and Cognitive Function in a Cohort of Older Men

Alexeeff, Stacey E., Schwartz, Joel, Coull, Brent A., Power, Melinda C., Weisskopf, Marc G., Spiro, Avron

2011

Overview

Background: Traffic-related particles induce oxidative stress and may exert adverse effects on central nervous system function, which could manifest as cognitive impairment. Objective: We assessed the association between black carbon (BC), a marker of traffic-related air pollution, and cognition in older men. Methods: A total of 680 men (mean ± SD, 71 ± 7 years of age) from the U.S. Department of Veterans Affairs Normative Aging Study completed a battery of seven cognitive tests at least once between 1996 and 2007. We assessed long-term exposure to traffic-related air pollution using a validated spatiotemporal land-use regression model for BC. Results: The association between BC and cognition was nonlinear, and we log-transformed BC estimates for all analyses [ln(BC)]. In a multivariable-adjusted model, for each doubling in BC on the natural scale, the odds of having a Mini-Mental State Examination (MMSE) score ≤ 25 was 1.3 times higher [95% confidence interval (CI), 1.1 to 1.6]. In a multivariable-adjusted model for global cognitive function, which combined scores from the remaining six tests, a doubling of BC was associated with a 0.054 SD lower test score (95% CI, -0.103 to -0.006), an effect size similar to that observed with a difference in age of 1.9 years in our data. We found no evidence of heterogeneity by cognitive test. In sensitivity analyses adjusting for past lead exposure, the association with MMSE scores was similar (odds ratio = 1.3; 95% CI, 1.1 to 1.7), but the association with global cognition was somewhat attenuated (-0.038 per doubling in BC; 95% CI, -0.089 to 0.012). Conclusions: Ambient traffic-related air pollution was associated with decreased cognitive function in older men.

• Publisher: National Institute of Environmental Health Sciences,US Department of Health and Human Services
• Subject: Age / Aged / Air / Air pollution / Air Pollution - adverse effects / Battery / Biological and medical sciences / Black carbon / Bones / Carbon-black / Central nervous system / Cognition / Cognition - drug effects / Cognition disorders / Cognitive ability / Cognitive models / Cognitive tests / Environment. Living conditions / Environmental aspects / Environmental pollutants toxicology / Health aspects / Heterogeneity / Humans / Land pollution / Land use / Male / Mathematical models / Medical sciences / Men / Mental concentration / Modeling / Models, Statistical / Older adults / Oxidative stress / Public health. Hygiene / Public health. Hygiene-occupational medicine / Risk factors / Sensitivity analysis / Toxicology / Traffic estimation / Vehicle Emissions - toxicity