Air pollution and the heart
· Air pollution, and specifically fine particulate matter, is associated with increased cardiovascular disease mortality.
· Air pollution has emerged as a potentially modifiable risk factor for the development of CVD.
· Whether air pollution is associated with episodes of AF was evaluated in a study of 176 patients with dual chamber implantable cardioverter-defibrillators that were capable of detecting episodes of AF. After follow-up of nearly two years, there were 328 episodes of AF lasting 30 seconds or more found in 49 patients.The potential impact of multiple parameters of air pollution, (measured hourly) on the development of AF was examined. The odds of AF increased significantly as the concentration of particulate matter increased in the two hours prior to the event. [J Am Coll Cardiol 2013; 62:816.]
· Multiple observational studies have demonstrated an association between fine particulate air pollution (primarily from the use of fossil fuels in automobiles, power plants, and for heating purposes) and cardiovascular and cardiopulmonary mortality as well as an increased risk for the development of acute coronary syndromes
· The Women's Health Initiative Observational study database of more than 65,000 postmenopausal women without prior CVD was used to evaluate the relation between a woman's long term exposure to air pollutants and the risk for a first cardiovascular event.For each 10 mcg/m3 increase in pollution concentration, there were significant increases in the risk of any cardiovascular event (hazard ratio 1.24), death from CVD (hazard ratio 1.76), and of cerebrovascular events (hazard ratio 1.35). [N Engl J Med 2007; 356:447.]
· Mortality data from nearly 450,000 patients in the American Cancer Society Cancer Prevention Study II data base were correlated to air pollution data, including average concentrations of ozone and fine particulate matter (≤2.5 micrometers in diameter [PM2.5]). In multivariate analysis PM2.5, but not ozone, concentration was significantly associated with the risk of death from cardiovascular causes (relative risk 1.2). [N Engl J Med 2009; 360:1085.]
· Further support for the significance of air pollution comes from a study of death rates in Dublin, Ireland before and after a ban on coal sales that led to a 70 percent reduction in black smoke concentrations [Lancet 2002; 360:1210.]. Adjusted cardiovascular deaths fell by 10.3 percent in the six years after the ban.
· Both the American Heart Association (2010) and the European Society of Cardiology (2015) have issued official statements discussing the association between long-term exposure to fine particulate air pollution and increased risk of developing cardiovascular disease [ Circulation 2010; 121:2331., Eur Heart J 2015; 36:83]
· In addition to long-term risk, short-term exposure to air pollutants (both ozone and fine particulate matter) has been associated with acute coronary ischemic events.’
· In a study of over 12,000 patients living in a defined geographic area, a short-term increase in fine ambient particulate matter positively correlated with an increase in acute ischemic coronary events [Circulation 2006; 114:2443]
· In a systematic review and meta-analysis of data from 34 studies, CO, NO2, SO2, and PM < 10 microns and less than 2.5 microns were all associated with an increased risk of myocardial infarction, with the overall population attributable risk ranging from 1 to 5 percent [JAMA 2012; 307:713]
· In a study of 772 patients with an acute MI, the risk of an MI was increased in the two hours after exposure to elevated levels of fine particles in the air (odds ratio 1.48 compared to low levels of fine particles); this effect lasted for up to 24 hours after exposure [Circulation 2001; 103:2810.].
· Possible mechanisms by which fine particulate air pollution may increase the risk of CVD include [Eur Heart J 2015; 36:83]
· An increase in mean resting arterial blood pressure through an increase in sympathetic tone and/or the modulation of basal systemic vascular tone [Circulation 2002; 105:1534]
· An increase in the likelihood of intravascular thrombosis through transient increases in plasma viscosity and impaired endothelial dysfunction [Circulation 2002; 106:933]
· The initiation and promotion of atherosclerosis [Circulation 2010; 121:2755]
· Multiple observational studies have demonstrated an association between fine particulate air pollution and distance from a major urban road or freeway and cardiovascular and cardiopulmonary mortality. However, there is conflicting evidence concerning whether air pollution is [ J Thromb Haemost 2010; 8:669.], or is not [ J Thromb Haemost 2011; 9:672.], causally related to VTE development