WEDNESDAY, Feb. 23 (HealthDay News) -- A major analysis of data
on potential triggers for heart attacks finds that many of the
substances and activities Americans indulge in every day -- coffee,
alcohol, sex, even breathing -- can all help spur an attack.
Because so many people are exposed to dirty air, air pollution
while stuck in traffic topped the list of potential heart attack
triggers, with the researchers pegging 7.4 percent of heart attacks
to roadway smog.
But coffee was also linked to 5 percent of attacks, booze to
another 5 percent, and pot smoking to just under 1 percent, the
European researchers found.
Among everyday activities, exerting yourself physically was
linked to 6.2 percent of heart attacks, indulging in a heavy meal
was estimated to trigger 2.7 percent, and sex was linked to 2.2
The researchers stressed that the risk for heart attack from any
one of these factors to a particular person at any given time is
extremely small. But spread out over the population, they can add
For example, air pollution is a minor trigger for heart attacks,
but since so many people are exposed to smog, it triggers many more
heart attacks than other more potent triggers, such as alcohol and
"Small risks can be highly relevant if they are widely distributed in the population," explained lead researcher Tim S. Nawrot, assistant professor of epidemiology at the Hasselt Centre for Environmental Sciences at Hasselt University in Diepenbeek, Belgium.
Commenting on the study, Dr. Gregg Fonarow, spokesman for the
American Heart Association and professor of cardiology at the
University of California, Los Angeles, added that "based on these
findings, improvement in air quality and reduction in traffic may
not just help the environment and increase quality of life, but
also substantially decrease the incidence of [heart attack]."
The report is published in the Feb. 24 online edition of
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
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
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.
"However, because they are infrequent, they cause a relatively small number of [heart attacks] in the population. At the opposite, ubiquitous triggers such as air pollution affect all the subjects in a city with high air pollution levels. Although the risk due to air pollution on each individual is moderate to small, the number of events triggered by air pollution in that city will be sizable," Baccarelli said.
For more information on heart attack, visit the
American Heart Association.