In a recent study from the University of Sydney, researchers found that respiratory infections like pneumonia, bronchitis, and influenza increased heart attack risk substantially. Now, they’re calling on doctors and medical experts to share this information with patients to so that they can recognize warning signs and protect themselves.
"Our findings confirm what has been suggested in prior studies that a respiratory infection can act as a trigger for a heart attack," said senior author and cardiologist Geoffrey Tofler. "Our message to people is while the absolute risk that any one episode will trigger a heart attack is low, they need to be aware that a respiratory infection could lead to a coronary event. So consider preventative strategies where possible, and don't ignore symptoms that could indicate a heart attack.”
Respiratory infection warning signs
The study analyzed 578 consecutive patients who had a heart attack due to a coronary artery blockage who had also reported recent respiratory infection symptoms. Each patient was interviewed about their activities before the cardiac event and were asked if they experienced any kind of respiratory illness.
The researchers found that 17% of patients had reported respiratory symptoms within 7 days of their heart attack and that 21% had shown symptoms within one month of their heart attack. Common symptoms that were reported included sore throat, cough, fever, and sinus pain, and some patients reported a diagnosis of pneumonia or bronchitis before the event.
"The data showed that the increased risk of a heart attack isn't necessarily just at the beginning of respiratory symptoms, it peaks in the first 7 days and gradually reduces but remains elevated for one month,” said Tofler.
Significantly increased risk
After analyzing all patients, the researchers determined that respiratory infections increased the risk of a heart attack 17-fold within the first seven days that patients contracted them. The results showed that middle respiratory tract infections were less risky in comparison, but they still carried a 13-fold risk increase.
There is no definitive answer as to why the respiratory infections increased heart attack risk, but Tofler says that it likely has something to do with an increased tendency towards blood clotting, inflammation, changes to blood flow, and the presence of toxins that can damage blood vessels. The researchers say that consumers should take extra measures to reduce their chance of infection, especially during times of the year when it is colder and infection is more likely.
"The next step is to identify treatment strategies to decrease this risk of heart attack, particularly in individuals who may have increased susceptibility," Tofler concluded.
The full study has been published in Internal Medicine Journal.