Respiratory Infections Raise Heart Attack Risk, Study Finds

A large number of people across the world suffer heart attacks each year. While smoking, family history, high cholesterol levels, high blood pressure and diabetes are the major risk factors for heart disease and heart attack, a new study suggests respiratory infections can also raise risk of heart attack.

A team of researchers from the University of Sydney in Australia found that both mild and severe respiratory infections might increase a person’s risk of having heart attack.

According to the researchers, respiratory infections such as pneumonia, the common influenza, and bronchitis all may make some individuals more susceptible to heart attacks by causing blood clots, inflammation or blood vessel damage.

“Possible reasons for why respiratory infection may trigger a heart attack include an increased tendency towards blood clotting, inflammation and toxins damaging blood vessels, and changes in blood flow,” said senior author of the study, Prof. Geoffrey Tofler, who is also a cardiologist at the University of Sydney, Royal North Shore Hospital, and Heart Research Australia.

To investigate a potential link between respiratory infections and heart attack risk, the researchers analysed 578 patients who had been hospitalized for a heart attack due to a blockage in their coronary arteries. The patients reported on their history of respiratory infection and informed about their most recent infections and whether they had any common symptoms pertaining to respiratory infection, including sore throat, cough, fever, sinus pain, and other flu-like symptoms, before suffering heart attack.

The results revealed that 17 percent of the patients had had symptoms of a respiratory infection up to 7 days before the heart attack, and 21 percent had reported a respiratory infection within 31 days.

Respiratory infections were estimated to increase the heart attack risk by 17 times. Even milder, upper respiratory tract infections appeared to raise the risk by 13.5 times, results showed.

Tofler said: “Our findings confirm what has been suggested in prior studies that a respiratory infection can act as a trigger for a heart attack.

“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 seven days and gradually reduces but remains elevated for one month.”

Tofler also informs that their next step is to identify preventive therapies for heart attack, specifically for people who are more susceptible to having a heart attack.

Meanwhile, the study authors have advised people to be aware that respiratory infections could cause a coronary event.

The study results appear in the Internal Medicine Journal.