The study looked at several holidays and dates of major sports events to see if there was an uptick in cases of myocardial infarction, also known as a heart attack, at those times.
WATCH: A recent study has found your risk of a heart attack is greatest on Dec. 24. Swedish research found people face a 40 per cent higher risk on Christmas Eve. As Heather Yourex-West explains, stress is likely to blame.
The researchers hypothesized that external factors — such as stress — could play a role in triggering a heart attack.
They studied more than 280,000 cases of patients with heart attack symptoms recorded in SWEDEHEART, a national cardiac data registry, from 1998 to 2013.
In a paper published in the journal BMJ on Dec. 12, the researchers said the risk of a heart attack was not found to be higher on Easter or during sporting events such as the World Cup, though the opposite was true for the Swedish Midsummer holiday, Christmas Eve and New Year’s Day.
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Of the occasions studied, the greatest risk of a heart attack was observed on Dec. 24, when occurrences were 37 per cent higher than the study’s control period two weeks prior.
The risk was higher for those over 75, diabetics, and people with history of coronary artery disease.
Heart attacks, which are more common during the morning, peaked at 10 p.m. on Christmas Eve, the study also found.
Possibly explaining the holiday bump, the authors noted that previous research has shown anger, anxiety, grief and stress increase the risk of a heart attack.
Similarly, there was a 20 per cent higher risk of heart attack on New Year’s Day.
The report suggested that the uptick could be linked to excesses the night before on New Year’s Eve — alcohol, food and sleep deprivation — combined with exposure to cold temperatures.
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Yet the authors said further research is warranted to explain their findings.
“Understanding what factors, activities, and emotions precede these myocardial infarctions and how they differ from myocardial infarctions experienced on other days could help develop a strategy to manage and reduce the number of these events,” they said.
The study was conducted by a team of researchers based out of four universities in Sweden, including five cardiologists.