AHA logoAir pollution is constantly increasing day by day. It may be one of the major causes of respiratory disorders like asthma and is also linked to heart attacks, strokes and cardiovascular ailments. A recent updated American Heart Association scientific statement suggests that people, particularly those at high cardiovascular risk, should limit their exposure to air pollution.

The researchers claim that possibly, an extremely strong evidence for fine particulate matter (PM2.5) having a causal relationship to cardiovascular disease has been noted. Combustion of fossil fuel from industry, traffic, and power generation is the major source of PM2.5. In particularly certain regions, biomass burning, heating, cooking, indoor activities and forest fires may also be relevant sources.

Robert D. Brook, M.D., lead author of the statement, explained, “Particulate matter appears to directly increase risk by triggering events in susceptible individuals within hours to days of an increased level of exposure, even among those who otherwise may have been healthy for years.”

Growing evidence probably suggests that longer-term PM2.5 exposures, such as over a few years, can lead to an even larger increase in these health risks. The American Heart Association claims that PM2.5 should be recognized as a ‘modifiable factor’ that contributes to cardiovascular morbidity and mortality.

The statement further concludes that a ‘small yet consistent’ association between short-term exposure to air pollution and pre-mature death may be noted. Also, a strong level of evidence supporting a relationship between air pollution and ischemic heart disease appeared. A ‘moderate, yet growing link’ between air pollution and heart failure and ischemic stroke was revealed and a ‘modest’ level of evidence supporting an association between air pollution and peripheral vascular diseases, irregular heartbeats and cardiac arrest was registered.

A higher risk from short-term PM2.5 exposure can possibly be faced by the elderly, those with diabetes and those with existing heart diseases, such as heart failure or coronary artery disease. Brook suggested that the foremost message for these high-risk groups remains that they should work to control their modifiable traditional risk factors – blood pressure, cholesterol, diabetes, and smoking. Although there are several means by which PM2.5 could possibly affect the cardiovascular system, the statement suggests that several components of PM2.5, once inhaled, can cause inflammation and irritate nerves in the lungs. These responses can have adverse effects on the body.

Brook said, “It’s possible that certain very small particles, or chemicals that travel with them, may reach the circulation and cause direct harm. The lung nerve-fiber irritation can also disrupt the balance of the nervous system throughout the body. These responses can increase blood clotting and thrombosis, impair vascular function and blood flow, elevate blood pressure, and disrupt proper cardiac electrical activity which may ultimately provoke heart attacks, strokes, or even death. These studies also indicate that there is no ‘safe’ level of PM2.5 exposure.”

The statement includes certain vital recommendations. It highlights that physicians should emphasize treatment of traditional cardiovascular risk factors, this may decrease patients’ susceptibility to air pollution. The researchers also call for awareness about the risks of air pollution amongst people especially those with cardiovascular disease. All healthcare professionals should educate patients without cardiovascular disease but who are at high risk, such as the elderly, individuals with metabolic syndrome or multiple risk factors and those with diabetes. Brook enlightened that exposure to air pollution should be reduced by implementing national policies as well as at the individual level.

The research has been updated in the American Heart Association scientific statement and is also, published in Circulation: Journal of the American Heart Association.