Prospective study of particulate air pollution exposures, subclinical atherosclerosis, and clinical cardiovascular disease: The Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air)

Abstract

The Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air) was initiated in 2004 to investigate the relation between individual-level estimates of long-term air pollution exposure and the progression of subclinical atherosclerosis and the incidence of cardiovascular disease (CVD). MESA Air builds on a multicenter, community-based US study of CVD, supplementing that study with additional participants, outcome measurements, and state-of-the-art air pollution exposure assessments of fine particulate matter, oxides of nitrogen, and black carbon. More than 7,000 participants aged 45-84 years are being followed for over 10 years for the identification and characterization of CVD events, including acute myocardial infarction and other coronary artery disease, stroke, peripheral artery disease, and congestive heart failure; cardiac procedures; and mortality. Subcohorts undergo baseline and follow-up measurements of coronary artery calcium using computed tomography and carotid artery intima-medial wall thickness using ultrasonography. This cohort provides vast exposure heterogeneity in ranges currently experienced and permitted in most developed nations, and the air monitoring and modeling methods employed will provide individual estimates of exposure that incorporate residence-specific infiltration characteristics and participant-specific time-activity patterns. The overarching study aim is to understand and reduce uncertainty in health effect estimation regarding long-term exposure to air pollution and CVD.

Figure 1.

Proposed timeline for completion of the primary components of the Multi-Ethnic Study of Atherosclerosis and Air Pollution, 2004–2014. (CAC, coronary artery calcium; EPA, Environmental Protection Agency; IMT, intima-medial thickness; MESA, Multi-Ethnic Study of Atherosclerosis).

Figure 2.

Prediction of annual average ambient concentrations of particulate matter less than 2.5 µm in diameter (PM_2.5) at participants' homes for 2007, by region, Multi-Ethnic Study of Atherosclerosis and Air Pollution. In this box-and-whisker plot, the central bars indicate the median values and the lower and upper ends of the rectangular boxes indicate the 25th and 75th percentiles, respectively. The top and bottom ends of the “whiskers” indicate the 10th and 90th percentiles, respectively, and the circles and asterisks indicate outliers greater than 1.5 and 3 interquartile ranges from the ends of the boxes, respectively. (CA, California; IL, Illinois; MD, Maryland; MN, Minnesota; NC, North Carolina; NY, New York).

Figure 3.

Integration of exposure modeling outputs to obtain personal exposure predictions for each participant in the Multi-Ethnic Study of Atherosclerosis and Air Pollution, 2004–2014. Parallelograms indicate input data, rectangles indicate statistical modeling processes, and ovals represent products. The curved arrows indicate that multiple external data sources are included as inputs to a given data set or process.