More Australians are beginning to understand why the flu is dangerous – but few are aware of its link to heart attack
Dr Lorcan Ruane, Resident Medical Officer at the Royal Brisbane and Women’s Hospital, warned that people have a higher risk of myocardial infarction in the weeks following a respiratory infection.
“When I say ‘respiratory infection’ I’m referring to diseases such as pneumonia and influenza, but also more common things such as… the common cold,” he said.
“Knowledge in the public is quite high regarding traditional risk factors for heart disease – these are things like obesity, poor diet, high blood pressure. These things are all long-term risk factors that tell you that a person has a higher risk of suffering a heart attack at some point in their lives.
“What’s also known now is that there exist short-term risk factors, or acute triggers. These things can tell us at what actual points in time a person is at a particularly high risk of having a heart attack and respiratory infection is one of these acute triggers.
“Awareness amongst the general public about the risk from acute triggers is much lower, and this was shown in our work where we investigated various triggers of heart attack.
“Not one subject listed respiratory infection as a possible cause of their heart attack, despite over 20% of our patients having had an infection prior to their heart attack,” Dr Ruane said.
They instead attributed their heart attack to more traditional long-term risk factors.
“In the week after an infection, a person’s risk of a heart attack is increased by up to 17 times.”
This risk is still elevated even after only mild common cold symptoms, and still persists for some weeks afterwards.
“These findings are quite significant in terms of public health because respiratory infections such as the common cold are so common,” Dr Ruane said. “Australians above the age of 50, i.e. those that already have a higher baseline risk of heart disease, will experience one to three colds each year.
“So for the average person they will potentially spend many weeks in each year in a state of significantly elevated risk, and because these infection are more common in the winter months it can be expected that the increased risk is concentrated in these months.
“And this is exactly what has been observed in previous studies: there does appear to exist a peak of heart attacks in the winter months.”
Dr Ruane said there was little evidence to support specific measures to avoid catching the common cold, but good hygiene is likely to be of benefit, as is maintaining general health to support the body’s immune system.
He strongly recommended influenza vaccination and cited a recent Australian study that found that not only did flu vaccination reduce the risk of contracting influenza itself, but also reduced the risk of heart attacks independent of other factors.
“The benefits of vaccinations in certain cases are not just limited to reducing the disease that they immunise against, there also exist secondary flow-on health benefits.”
When a person already has a respiratory infection, it’s helpful if people are aware of the link to heart attacks.
“I’m not saying that every time someone gets a runny nose they need to bring themselves to ED, but if they are aware of the increased risk they will be able to respond better to the potential signs of a heart attack if they were to occur,” Dr Ruane said.
“For instance if a patient develops some chest pain, or becomes short of breath, they should not dismiss these symptoms as merely a result of their respiratory infection.”