In their research, Nawrot's team looked at 36 studies examining environmental triggers for heart attacks. In their review, known as a meta-analysis, the researchers looked for common threads that could establish how these factors might rank in risk.
In terms of risk, the team found that air pollution increased a person's risk of having a heart attack by just under 5 percent. In contrast, coffee increased the risk by 1.5 times, alcohol tripled the risk, and cocaine use increased the odds for heart attack 23-fold.
However, because only a small number of people in the entire population are exposed to cocaine, while hundreds of millions are exposed to air pollution daily, air pollution was estimated to cause more heart attacks across the population than cocaine.
Even emotional states can sometimes trigger a heart attack, the team found. For example, negative emotions in general were linked to almost 4 percent of heart attacks while anger, specifically, was linked to just over 3 percent. Even "good" emotional states were tied to 2.4 percent of heart attacks, the study authors noted.
Although exposure to secondhand smoke was not included in the analysis, the effects are probably of the same magnitude as air pollution, the authors added. Where bans on smoking in public places exist, the rate of heart attacks has dropped an average of 17 percent, they noted.
Dr. Andrea Baccarelli, the Mark and Catherine Winkler associate professor of environmental epigenetics at the Harvard School of Public Health and coauthor of an accompanying journal editorial, said that "this work stands as a warning against overlooking the effects of moderate risks when they affect the entire population."
At the same time, the researchers show that powerful triggers such as cocaine are very detrimental for those (relatively few) subjects who are exposed to them, he said.
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