Air Pollution and Traffic Linked to Heart Attacks

Air Pollution And Traffic Linked To Heart Attacks

A heart attack, or acute myocardial infarction, can occur due to various risk factors like excessive exercise, stress, air pollution, or even a heavy meal. This study was conducted to review literature for all such triggering factors and estimate the level of risk posed by each of them. Results showed that “use of cocaine, a heavy meal, smoking of marijuana, negative emotions, physical exertion, positive emotions, anger, sexual activity, traffic exposure, respiratory infections, coffee consumption and air pollution” were some of the important triggers of heart attacks.

Heart attacks are known to be caused by various extreme conditions. Although studies of the pathology of heart attacks show that treatment of underlying risk factors like high cholesterol and blood pressure may be important, there are other factors that can be easily controlled. Some of these factors are related to public health measures. In this study, these triggers have been assembled into a comprehensive list. This research was undertaken to uncover the importance of public health triggers that include alcohol, anger, physical exertion, the use of marijuana, and air pollution, among others. The authors looked at risk factors that depended on the strength between a trigger and what caused the trigger. The level of risk was also determined based on the amount of exposure a population would have to the triggering factors. This study looked at earlier studies to compare the various triggers that lead to an increased risk of heart attacks.

For this study, researchers used the Internet to search scientific resources, like the PubMed database and the Web of Science database, for triggering factors of heart attacks that did not eventually lead to death. Studies on these websites published from January 1960 through January 2010 were included. The researchers then used statistical measures to analyze the risk that each triggering factor may have posed to a population. A total of 36 studies were found to be useful for the review.

Results/Key findings
* Maximum posed risk to minimum posed risk ranged in a descending manner from factors like cocaine addiction, consumption of a large meal, smoking pot or marijuana, negative emotions or feelings, excessive exertion, anger, sexual intercourse, traffic, infections of the respiratory tract, coffee intake, and air pollution.
* The highest population risk was noted with exposure to traffic (7.4 percent), excessive physical strain (6.2 percent), alcoholic beverages (5 percent), coffee drinking (5 percent), negative feelings (3.9 percent), anger (3.1 percent), large meal (2.7 percent), positive feelings (2.4 percent), sexual intercourse (2.2 percent), use of cocaine (0.9 percent), use of marijuana (0.8 percent), and infections of the respiratory tract like pneumonia, etc. (0.6 percent).

Next steps/Shortcomings
Authors agree that while including studies for their review, they did not consider whether the research was well or poorly designed. They write that this could mean that some of the triggering factors were not as clearly defined as others. Also, they did not include studies that reported short-term risk factors, like a natural calamity or a World Cup series that led to sporadic cases of heart attacks. They also could not include secondhand smoke as one of the triggers since it has not been studied in detail. They add that future studies that estimate traffic exposure — the air pollution, the stress, or both — could prove to be an important triggering factor.

The authors have concluded that air pollution and exposure to traffic are leading risk factors that may result in heart attacks. They add that public health measures directed toward reducing these factors could assist in reducing the risk of heart attacks. Although the risk from traffic exposure is between 5 and 7 percent, which is similar to other known factors like excessive exercise, alcoholism, and excessive coffee consumption, these figures become greater when actually translated into numbers of the population. Thus, measures to curb air pollution and further studies to explore road rage as heart attack triggers are warranted to help prevent these health risks of heart attacks.

For More Information:
Public Health Importance of Triggers of Myocardial Infarction: A Comparative Risk Assessment
Publication Journal: Lancet, February 2011
By Tim Nawrot, PhD; Laura Perez, PhD; Hasselt University, Diepenbeek, Belgium, and the Swiss Tropical and Public Health Institute, and University of Basel, Switzerland

*FYI Living Lab Reports Are Summaries of the Original Research.

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