Final Report: Long-term Exposure to Ambient Particulate Matter and Subclinical Atherosclerosis

EPA Grant Number: CR830543
Title: Long-term Exposure to Ambient Particulate Matter and Subclinical Atherosclerosis
Investigators: Diez Roux, Ana V. , Auchincloss, Amy H , Dvonch, J. Timothy , Keeler, Gerald J. , O'Neill, Marie , Raghunathan, Trivellore , Samson, Perry
Institution: University of Michigan , Drexel University
EPA Project Officer: Chung, Serena
Project Period: April 1, 2003 through March 31, 2006 (Extended to March 31, 2008)
Project Amount: $768,990
RFA: Epidemiologic Research on Health Effects of Long-Term Exposure to Ambient Particulate Matter and Other Air Pollutants (2002) RFA Text |  Recipients Lists
Research Category: Health Effects , Particulate Matter , Air

Objective:

The general aim of the project was to determine if long-term exposure to airborne particles is related to the development of atherosclerosis. Objectives were to examine: (1) the relationship between long-term exposure to air particles and the prevalence of subclinical atherosclerotic disease after controlling for established cardiovascular risk factors and key co-pollutants, (2) if established cardiovascular risk factors modify the relation between long-term exposure to airborne particles and prevalence of subclinical disease, (3) if associations between long-term exposure and atherosclerosis are similar in different race/ethnic groups, and (4) associations between current and recent exposure to air particles and inflammatory markers (a potential biologic mechanism linking air particle exposure to atherosclerosis).

Summary/Accomplishments (Outputs/Outcomes):

(1) Data collection and data set creation

Residential history information since 1982 was collected on all MESA participants attending MESA exams 2 and 3. All addresses were geocoded, creating a file containing the residential location for each participant on each month between August 1982 and the date of the baseline exam. We also have completed compilation of all relevant historical PM2.5, PM10, TSP, co-pollutants (NO2, SO2, CO, O3), atmospheric temperature, humidity, and visibility data for the full country and the full historical period. This involved extensive processing of crude monitor data and construction of monthly averages for each month and location. In addition, we also obtained national data on roads highways for the whole country and created measures of distance to major roads for all historical locations.

In addition to historical air pollution data, we also compiled data on pollutant levels during the time of the MESA baseline examination (2000-2002) for the six MESA sites. After data cleaning and checking, we created a variety of exposure measures for the residential locations of participants at baseline, including values at the nearest monitor, averages within a certain distance of the residential location, and means for all values within the MESA site. These measures were constructed for a variety of time periods (on the day of the visit, as well as means for 2, 7, 30, and 60 days prior to the visit). These exposure measures have been investigated in relation to a variety of outcomes as detailed below.

An additional data processing task included updating and processing baseline and subsequent MESA participant addresses for the period encompassing the four MESA exams. After compiling and creating a longitudinal data set, we geocoded all addresses using two geocoding platforms (Mapping Analytics and Tele Atlas). These geocodes will be invaluable in future prospective analyses of the MESA cohort.

(2) Analyses and results for each project objective

We conducted a series of statistical analyses related to each of the objectives of the project. These analyses resulted in six scientific manuscripts (four of which have been published and two of which are currently being reviewed by co-authors) and three presentations at scientific meetings. Details on the technical approach and the findings for each objective are provided in the subsequent sections.

TECHNICAL APPROACH AND KEY RESULTS

(1) Analyses related to Objectives 1, 2, and 3

Objective 1. To examine the relationship between long-term exposure to air particles and the prevalence of subclinical atherosclerotic disease in an ethnically diverse sample after controlling for established cardiovascular risk factors.

Objectives 2 and 3. To examine the extent to which established cardiovascular risk factors or race/ethnicity modify the relation between long-term exposure to airborne particles and prevalence of subclinical disease.

A manuscript reporting associations between long term PM2.5 and PM10 exposures and measures of subclinical atherosclerosis (as well as interactions between PM exposures and established risk factors and race/ethnicity) was recently published in the American Journal of Epidemiology.

(2) Analyses related to Objective 4

Objective 4. To examine acute associations between current exposure to air particles and inflammatory markers.

A manuscript reporting associations between recent PM2.5 and PM10 exposures and inflammatory markers has been published in the American Journal of Epidemiology.

(3) Additional analyses and results related to Project Objectives

In addition to addressing the specific objectives of the project, we conducted a set of additional analyses in related areas. These included analyses of the effects of blood pressure on a variety of measures of blood pressure and vascular function (which could be one of the mechanistic pathways through which PM exposures affect atherosclerosis and cardiovascular events) as well as methodological work on the imputation on long-term PM exposures.

3.1. PM exposures and blood pressure

Using the data described above, we investigated the relationship between PM exposures and a variety of blood pressure-related outcomes.

3.2. PM exposures and albumin excretion

PM exposures also were examined in relation to albumin excretion, an indicator of subclinical alterations of microvascular function, which may be affected by PM exposures.

3. 3. PM exposures and arterial stiffness

Arterial stiffness has recently emerged as yet another marker of subclinical vascular disease, which may be affected by PM exposures.

3.4. Methodologic work on the imputation of long-term exposures

A key challenge in our project was the estimation of long-term exposures based on sparse historical data. Our statistical team developed a methodologic approach to this problem. An abstract based on these findings was presented at an international meeting and a manuscript is being finalized.

Conclusions:

We have fully addressed the objectives of the project and also have conducted additional analyses in related areas. Results have been published in top epidemiology and environmental health journals. In the process, we also have created a unique resource on country-wide historical exposures, which future studies will be able to build on. We also have updated and processed MESA address information that will be invaluable in prospective analyses planned as part of the larger MESA Air Project.

In summary, we found that greater long term (20 year) PM10 and PM2.5 exposures were associated with greater subclinical atherosclerosis as measured by carotid intimal-medial thickness after adjustment for risk factors. We also documented positive associations between recent PM2.5 exposures and blood pressure (specifically systolic blood pressure and pulse pressure). In addition, chronic PM exposures were also associated with greater carotid arterial stiffness, although this association was reversed at high PM levels. Taken together, these findings suggest a possible etiologic role of PM exposures on the development of atherosclerosis through mechanisms involving effects on arterial stiffness and blood pressure. In contrast, we found only weak evidence that PM exposures are related to systemic inflammation or to vascular function as assessed by microalbuminuria. Because our results were suggestive but not conclusive, further examination of inflammation and vascular function as mechanistic links relating air pollution to cardiovascular disease is warranted. We found no consistent evidence that PM exposures interact with established cardiovascular risk factors or race/ethnicity. Our results suggest that air pollution exposures have a measurable impact of some indicators of subclinical cardiovascular disease. A limitation of the work was the reliance on ambient monitor data with limited spatial resolution and absence of detailed time-activity data for participants which would allow finer modeling of exposures. Both limitations are being addressed as part of the recently funded MESA project. These measurement challenges may have limited our ability to detect weak albeit meaningful effects of air pollution exposures on subclinical disease.


Journal Articles on this Report : 6 Displayed | Download in RIS Format

Other project views: All 11 publications 6 publications in selected types All 6 journal articles
Type Citation Project Document Sources
Journal Article Auchincloss AH, Diez Roux AV, Dvonch JT, Brown PL, Barr RG, Daviglus ML, Goff Jr. DC, Kaufman JD, O'Neill MS. Associations between recent exposure to ambient fine particulate matter and blood pressure in the Multi-Ethnic Study of Atherosclerosis (MESA). Environmental Health Perspectives 2008;116(4):486-491. CR830543 (2005)
CR830543 (Final)
R831697 (2009)
R831697 (2010)
R831697 (2011)
R831697 (2012)
R831697 (2013)
R831697 (Final)
  • Full-text from PubMed
  • Abstract from PubMed
  • Associated PubMed link
  • Full-text: ResearchGate-Full Text PDF
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  • Abstract: ResearchGate - Abstract
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  • Journal Article Diez Roux AV, Auchincloss AH, Astor B, Barr RG, Cushman M, Dvonch T, Jacobs Jr. DR, Kaufman J, Lin X, Samson P. Recent exposure to particulate matter and C-reactive protein concentration in the Multi-Ethnic Study of Atherosclerosis. American Journal of Epidemiology 2006;164(5):437-448. CR830543 (2005)
    CR830543 (Final)
  • Abstract from PubMed
  • Full-text: Oxford-Full Text PDF
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  • Abstract: Oxford-Abstract and Full Text HTML
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  • Journal Article Diez Roux AV, Auchincloss AH, Franklin TG, Raghunathan T, Barr RG, Kaufman J, Astor B, Keeler J. Long-term exposure to ambient particulate matter and prevalence of subclinical atherosclerosis in the Multi-Ethnic Study of Atherosclerosis. American Journal of Epidemiology 2008;167(6):667-675. CR830543 (2005)
    CR830543 (Final)
    R831697 (2009)
    R831697 (2010)
  • Abstract from PubMed
  • Full-text: Oxford-Full Text PDF
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  • Abstract: Oxford-Abstract and Full Text HTML
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  • Journal Article O'Neill MS, Diez-Roux AV, Auchincloss AH, Franklin TG, Jacobs Jr DR, Astor BC, Dvonch JT, Kaufman J. Airborne particulate matter exposure and urinary albumin excretion: the Multi-Ethnic Study of Atherosclerosis. Occupational and Environmental Medicine 2008;65(8):534-540. CR830543 (2005)
    CR830543 (Final)
    R827353 (Final)
    R831697 (2009)
    R831697 (2010)
  • Full-text from PubMed
  • Abstract from PubMed
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  • Abstract: BMJ-Abstract
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  • Journal Article O'Neill MS, Diez-Roux AV, Auchincloss AH, Shen M, Lima JA, Polak JF, Barr RG, Kaufman J, Jacobs Jr. DR. Long-term exposure to airborne particles and arterial stiffness: the Multi-Ethnic Study of Atherosclerosis (MESA). Environmental Health Perspectives 2011;119(6):844-851. CR830543 (Final)
    R831697 (2011)
    R831697 (2012)
    R831697 (2013)
    R831697 (Final)
  • Full-text from PubMed
  • Abstract from PubMed
  • Associated PubMed link
  • Full-text: EHP-Full Text HTML
  • Other: EHP-Full Text PDF
  • Journal Article Park SK, Auchincloss AH, O'Neill MS, Prineas R, Correa JC, Keeler J, Barr RG, Kaufman JD, Diez Roux AV. Particulate air pollution, metabolic syndrome, and heart rate variability: the Multi-Ethnic Study of Atherosclerosis (MESA). Environmental Health Perspectives 2010;118(10):1406-1411. CR830543 (Final)
    R831697 (2010)
    R831697 (2011)
    R831697 (2012)
    R831697 (2013)
    R831697 (Final)
  • Full-text from PubMed
  • Abstract from PubMed
  • Associated PubMed link
  • Full-text: EHP-Full Text HTML
  • Other: EHP-Full Text PDF
  • Supplemental Keywords:

    Exposure, ambient air, health effects, sensitive populations, epidemiology, RFA, Health, Scientific Discipline, PHYSICAL ASPECTS, Air, particulate matter, Health Risk Assessment, Risk Assessments, Environmental Monitoring, Physical Processes, human health effects, long term exposure, exposure, airborne particulate matter, atherosclerosis, air pollution, particle exposure, human exposure, ambient particle health effects, Acute health effects, aersol particles, human health risk

    Progress and Final Reports:

    Original Abstract
  • 2003 Progress Report
  • 2004 Progress Report
  • 2005 Progress Report
  • 2006