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Exposure to Black Carbon and Cognitive Function in a Cohort of Older Men

Power, Melinda C.1,2; Weisskopf, Marc G.1,2; Alexeeff, Stacey E.2; Coull, Brent A.3; Spiro, Avron III4,5; Schwartz, Joel1,2

doi: 10.1097/01.ede.0000392306.56000.80
Abstracts: ISEE 22nd Annual Conference, Seoul, Korea, 28 August–1 September 2010: Air Pollution - Exposure Characterization and Health Effects

1Department of Epidemiology, Harvard School of Public Health, Boston, MA; 2Department of Environmental Health, Harvard School of Public Health, Boston, MA; 3Department of Biostatistics, Harvard School of Public Health, Boston, MA; 4Veterens Affairs Boston Healthcare System, Boston, MA; and 5Department of Epidemiology, Boston University School of Public Health, Boston, MA.

Abstracts published in Epidemiology have been reviewed by the societies at whose meetings the abstracts have been accepted for presentation. These abstracts have not undergone review by the Editorial Board of Epidemiology.


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Limited experimental and epidemiologic evidence suggests an association between ambient air pollution and cognitive function; however, only 1 epidemiologic study has considered this association in older adults. The objective of this study is to consider the relationship between long-term exposure to traffic-related air pollution and cognitive test performance in a population of older men.

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Long-term exposure to traffic-related air pollution was assessed using a validated spatiotemporal land-use regression model for black carbon exposure. Estimates of black carbon exposure at each participant's residence in the year prior to the first eligible cognitive assessment were used to provide a measure of long-term exposure. Cognitive function was assessed for each participant using a battery of cognitive tests administered every 3–5 years. All cognitive test scores were z-transformed to promote comparability and combination in analyses. Linear mixed models were used to estimate the association between black carbon and (a) performance on each individual cognitive test and (b) global cognitive performance.

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On average, age at the first eligible cognitive assessment was 71 (range, 51–97). For all 8 of the cognitive test scores, point estimates from multivariate-adjusted models suggest an adverse effect of traffic-related air pollution on cognitive test performance. When considering effects of black carbon exposure on global cognitive performance, a 1 standard deviation increase in log black carbon exposure was associated with a decline of 0.042 standard deviations in cognitive test score (95% CI: −0.002, −0.081) in multivariate-adjusted models, an effect size similar to the difference observed with a increase in age of approximately 1 year. There was no evidence of heterogeneity by cognitive test.

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This study provides evidence that ambient traffic-related air pollution may have adverse effects on cognitive function in older men.

© 2011 Lippincott Williams & Wilkins, Inc.