Public Health Importance of Triggers of Myocardial Infarction: A Comparative Risk Assessment

Study Questions:

What is the importance and relevance of triggers for myocardial infarction (MI)?


Literature from PubMed and the Web of Science (January 1960 to January 2010) was examined for studies which identified triggers of nonfatal MI. Data from these studies were used to calculate population-attributable fractions for MI risk. When feasible, the authors completed a meta-regression analysis for studies which examined the same trigger.


Of the 528 references identified, a total of 36 epidemiological studies were included. Exposure prevalence for triggers ranged from 0.04% for cocaine to 100% for air pollution. The reported odds ratios ranged from 1.05 to 23.7. Trigger risks for MI, ranked from highest to lowest risk, included cocaine, heavy meal, smoking of marijuana, negative emotions, physical exertion, positive emotions, anger, sexual activity, traffic exposure, respiratory infections, coffee consumption, and air pollution. Air pollution as a trigger was based on a difference of 30 µg/m3 in particulate matter with a diameter <10 µm (PM10). Accounting for the odds ratio and prevalence of exposure, the highest population-attributable fraction for MI risk was related to traffic exposure (7.4%) followed by physical exertion (6.2%), alcohol (5.0%), coffee (5.0%), negative emotions (3.9%), anger (3.1%), heavy meal (2.7%), positive emotions (2.4%), sexual activity (2.2%), cocaine use (0.9%), marijuana use (0.8%), and respiratory infections (0.6%).


The authors concluded that air pollution is an important risk for MI, given the magnitude of risk and the prevalence in the population.


This well-done analysis demonstrates that risks which may appear to be small may have significant public health importance if they are present for significant amounts of time. These results suggest that reducing exposure to air pollution could lead to reductions in MI.

Clinical Topics: Prevention, Smoking

Keywords: Respiratory Tract Infections, Myocardial Infarction, Public Health, Marijuana Smoking, Particulate Matter, Risk Assessment, Smoking

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