title: Structural equation modeling of the inflammatory response to traffic air pollution.
abstract: Several epidemiological studies have reported conflicting results on the effect of traffic-related pollutants on markers of inflammation. In a Bayesian framework, we examined the effect of traffic pollution on inflammation using structural equation models (SEMs). We studied measurements of C-reactive protein (CRP), soluble vascular cell adhesion molecule-1 (sVCAM-1), and soluble intracellular adhesion molecule-1 (sICAM-1) for 749 elderly men from the Normative Aging Study. Using repeated measures SEMs, we fit a latent variable for traffic pollution that is reflected by levels of black carbon, carbon monoxide, nitrogen monoxide and nitrogen dioxide to estimate its effect on a latent variable for inflammation that included sICAM-1, sVCAM-1 and CRP. Exposure periods were assessed using 1-, 2-, 3-, 7-, 14- and 30-day moving averages previsit. We compared our findings using SEMs with those obtained using linear mixed models. Traffic pollution was related to increased inflammation for 3-, 7-, 14- and 30-day exposure periods. An inter-quartile range increase in traffic pollution was associated with a 2.3% (95% posterior interval (PI): 0.0-4.7%) increase in inflammation for the 3-day moving average, with the most significant association observed for the 30-day moving average (23.9%; 95% PI: 13.9-36.7%). Traffic pollution adversely impacts inflammation in the elderly. SEMs in a Bayesian framework can comprehensively incorporate multiple pollutants and health outcomes simultaneously in air pollution-cardiovascular epidemiological studies.
authors.affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA. ebaja@hsph.harvard.edu
authors.forename: Emmanuel S
authors.initials: ES
authors.lastname: Baja
authors.forename: Joel D
authors.initials: JD
authors.lastname: Schwartz
authors.forename: Brent A
authors.initials: BA
authors.lastname: Coull
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Wellenius
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Wellenuis
authors.forename: Pantel S
authors.initials: PS
authors.lastname: Vokonas
authors.forename: Helen H
authors.initials: HH
authors.lastname: Suh
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D006801:Humans; D007249:Inflammation / Q000503:physiopathology*; D008137:Longitudinal Studies; D008962:Models, Theoretical; D001335:Vehicle Emissions
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions