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Adverse Cardiovascular Effects of Air Pollution

Authors: Nicholas L. Mills, MD; Ken Donaldson, PhD; Paddy W. Hadoke, MD; Nicholas A. Boon, MD; William MacNee, MD; Flemming R. Cassee, PhD; Thomas Sandström, MD, PhD; Anders Blomberg, MD, PhD; David E. Newby, DM, PhDFaculty and Disclosures


Summary and Introduction


Air pollution is increasingly recognized as an important and modifiable determinant of cardiovascular disease in urban communities. Acute exposure has been linked to a range of adverse cardiovascular events including hospital admissions with angina, myocardial infarction, and heart failure. Long-term exposure increases an individual's lifetime risk of death from coronary heart disease. The main arbiter of these adverse health effects seems to be combustion-derived nanoparticles that incorporate reactive organic and transition metal components. Inhalation of this particulate matter leads to pulmonary inflammation with secondary systemic effects or, after translocation from the lung into the circulation, to direct toxic cardiovascular effects. Through the induction of cellular oxidative stress and proinflammatory pathways, particulate matter augments the development and progression of atherosclerosis via detrimental effects on platelets, vascular tissue, and the myocardium. These effects seem to underpin the atherothrombotic consequences of acute and chronic exposure to air pollution. An increased understanding of the mediators and mechanisms of these processes is necessary if we are to develop strategies to protect individuals at risk and reduce the effect of air pollution on cardiovascular disease.


The adverse effects of air pollution on cardiovascular health have been established in a series of major epidemiologic and observational studies.[1-4] Even brief exposures to air pollution have been associated with marked increases in cardiovascular-related morbidity and deaths from myocardial ischemia, arrhythmia, and heart failure.[5-7]

The WHO estimates that air pollution is responsible for 3 million premature deaths each year.[8] This pathologic link has particular implications for low-income and middle-income countries with rapidly developing economies in which air pollution concentrations are continuing to rise. In developed nations, major improvements in air quality have occurred over the last 50 years, yet the association between air pollution and mortality is still evident, even when pollution levels are below current national and international targets for air quality. No apparent threshold exists below which the association no longer applies.[9]

The breadth, strength, and consistency of the evidence provides a compelling argument that air pollution, especially traffic-derived pollution, causes cardiovascular disease.[10-12] However, these epidemiologic and observational data are limited by imprecise measurements of pollution exposure, and the potential for environmental and social factors to confound the apparent associations. For a causal association to have scientific credence, a clear mechanism must be defined. In this Review, we discuss potential pathways through which air pollution mediates these adverse cardiovascular effects. We also explore the preclinical and clinical evidence for the main mechanisms that link air pollution with cardiovascular disease.

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