New Study Finds That Heart Attacks Are Linked To The Common Flu

2018 is already proving to be the year of the flu. In the second week of January, more people were seen by doctors for exhibiting flu-like symptoms than at any point in the past decade. It’s caused the death of more children than expected and is already the most widespread flu on record in the 13 years since officials started keeping track. All of this is surely not being helped by a flu vaccine that some are calling increasingly less effective.

A New Risk From Influenza

To make matters worse, scientists have discovered evidence that the virus may be even more dangerous than previously assumed. According to a paper published in the New England Journal of Medicine by a group of researchers from Canada, the flu has now been cited as an instigator of heart attacks in adults. In an interview with science journal STAT, Jeffrey Kwong, a physical and epidemiologist at the Institute for Clinical Evaluative Sciences, has stated that “influenza, without question, is associated with [heart attacks].”
The researchers have looked at both lab and hospital data from facilities in Ontario from 2009 to 2014, and found that during that time there were 19,729 different cases of people—all over the age of 35—who exhibited symptoms of the flu. Additionally, the discharge records at those same hospitals show that of those tested positive for the flu, 332 patients were admitted to a hospital for a heart attack within roughly a year before the contracted the flu or 51 weeks after.
The research went on to minimize the case study, shrinking the rate to a two-year period and studying the rates of heart attacks within a week of getting the flu. Their research found that there were nearly 20 instances in which heart attacks followed within seven days of a flu diagnosis. Those 334 heart attacks occurred at a rate of roughly 3.3 per week, which led researchers to the conclusion that the risk of a heart attack increased by a factor of almost six when it followed a conclusive flu diagnosis.
This is, in many ways, a logical conclusion, if not an immediately obvious one. When the body is fighting off a virus, especially one as debilitating and nervous-system wrecking as the flu, it is going through extended periods of stress. Over the years, scientist found that some associations exist between heart attacks and other illnesses that share symptoms with the flu, but the lack of quantitative study—due to the fact that people don’t typically get tested for the flu—has mad conclusive data lacking.

Understanding the Research

The statistics do have a caveat, however. Though broadly applicable, they don’t apply in the same way to everyone. Heart attacks tend to be more common amongst men between the ages of 60 and 70; that number goes up to more than 30% of men above the age of 80, while for women, data shows those statistics being nearly 10% lower. The flu tends to be most drastically dangerous for people who are 65 or older, meaning that the most susceptible amongst us for both heart attacks and the flu tend to fall in exactly the same sweet spot (though the study did not make note of whether the correlation proved stronger for men than for women).
Heart attacks are uncommon for those who are younger, though not entirely unknown. According to Quartz, “less than 1% of the population has a heart attack before 40, and only about 6% of men and 5% of women do before 60. The median age of patients who had heart attacks in this study was 77—well within a group already at elevated risk for heart attack and severe flu symptoms.” All of which is to say that as we head towards a future in which superbugs are killing patients at a rapid rate, the time has come to reconfigure the flu shot as a remedy for more than just the winter—it could save your heart too.