About MESA Air

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What is the MESA Air study?

The purpose of the Multi-Ethnic Study of Atherosclerosis (MESA) Air Pollution study is to relate how the amount of air pollution you breathe may be related to early stages of heart diseases and diseases of the blood vessels and lung. The initial MESA Air study, supported by the United States Environmental Protection Agency, was completed in 2014 but MESA Air scientists are continuing to pursue this research with funding from the Environmental Protection Agency, the National Institutes of Health, and the Health Effects Institute.

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The MESA Air Pollution study collected air samples from the places where study participants live. The sample results allow the researchers to estimate the air pollution levels, and see how those levels differ between regions or show changes over time. At the same time, non-invasive health tests track whether study participants showed subtle changes in their heart and blood vessels.

Some of the participants have had CT scans to see how much calcium has built up in their coronary artery (blood vessels that supply blood to the heart). These participants also had an ultrasound to determine the thickness of the walls of their carotid arteries (arteries in their neck). Both of these tests can detect subtle signs of atherosclerosis. Blood tests on a smaller group determined the degree of inflammation and vascular function.

These changes are usually so small that the participants don't have any symptoms, and may include plaques or deposits in the blood vessels, and signs of inflammation in the blood. The health test results were adjusted for age, race/ethnicity, socioeconomic status, and specific cardiovascular risk factors such as diabetes, high blood pressure, smoking, and diet.

The MESA Air Pollution study adds state-of-the-art air pollution exposure information to the health information. Several types of air pollution monitoring was completed including long-term daily monitoring at specific locations, widespread community-based monitoring, indoor and outdoor monitoring at a participant’s home, and personal monitoring. The sample results are used to model each participant’s long-term individual exposure. It also provides information on a subject’s proximity to pollution sources, as well as the efficiency of buildings to “block” pollution (“infiltration efficiency”).

The health results and the air pollution monitoring results are then compared statistically to see if exposure to air pollution increases the risk of atherosclerosis. The study also investigates whether major cardiovascular events, such as heart attacks and strokes, are associated with long-term exposure to polluted air.

What do we know about the link between air pollution and heart disease?

Building on MESA

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The MESA Air study was built on the foundation of MESA, a large study of heart disease in a diverse, population-based sample of men and women aged 50-89. It is funded by the National Heart Lung and Blood Institute of the National Institutes of Health . The MESA study is located in six geographic areas, or field centers.

Our study takes advantage of specialized diagnostic centers working on the MESA study. Laboratory work at the University of Vermont, evaluations of computed tomography (CT) scans by Los Angeles Biomedical Research Institute, and the analysis by Tufts-New England Medical Center of ultrasound scans to provide valuable information on the subtle progression of cardiovascular disease in participants.

A tremendous amount of data was collected and analyzed during the ten years of the MESA Air Pollution study. This includes research efforts by the MESA study, ongoing work by the MESA Air Pollution study, and continued follow-up of all study participants. The Collaborative Health Studies Coordinating Center, also located at the University of Washington, was responsible for data collection, storage, and distribution. Biostatisticians with the Collaborative Health Studies Coordinating Center and other University of Washington departments closely examine the collected data to see what relationship may exist between air pollution and cardiovascular disease.

Additional Resources

Official MESA Website

Collaborative Health Studies Coordinating Center

National Heart, Lung, and Blood Institute (NIH/NHLBI)

Environmental Protection Agency (EPA)

American Heart Association

American Lung Association