Rise in Christmas Season Cardiac Deaths Not Necessarily Linked to Cold Weather, Study Finds

Study sheds light on possible reasons for rise in cardiac deaths.

ByABC News
December 22, 2016, 4:00 PM

— -- Doctors in the U.S. have long known that fatal cardiac events seem to occur more frequently during the winter holidays, but deciphering if these events are related to weather, holiday stress or some other cause has been difficult to parse out.

But a study published today in the Journal of the American Heart Association offers some evidence that cold weather may not be behind the uptick in cardiac deaths -- long thought to be a possible culprit since it can put additional strain on the body.

"What is always difficult in observational studies such as this is separating correlation from causation," said Dr. Richard Josephson, a cardiologist at University Hospitals Harrington Heart and Vascular Institute at UH Cleveland Medical Center. Josephson was not involved in this study.

"In the U.S. and England or in Great Britain there is an upsurge in death around Christmas. It could be related to holiday or it could be related to the weather," Josephson told ABC News.

To find out if weather was behind this increase in cardiac deaths during the holidays, the researchers from multiple institutions, including the University of Melbourne and University of Auckland, studied mortality data from New Zealand, where summer coincides with the holiday season.

After examining 25 years of data from the New Zealand Ministry of Health, the researchers were able to see if fatal cardiac events increased during the holiday season. Despite the naturally warm weather in December and January, they found that 4.2 percent more people die from cardiac-related causes during the Christmas period -- Dec. 25 to Jan. 7 -- compared to the rest of the year. Only deaths that took place outside a hospital were counted.

The researchers found that these deadly cardiac events also seemed to affect slightly younger people during the Christmas period compared to the rest of the year. During the Christmas period the average age of those who died via cardiac-event was 76, while during the rest of the year the average age was 77.

As a result of the findings, the researchers theorize that the uptick in cardiac death around the holidays is likely not due to cold weather. Instead they theorize it might be due to holiday stress, changes in diet or alcohol consumption, delay in seeking medical care or even due people who are extremely sick and want to live long enough to get through the holidays with family.

"The Christmas holiday period is a common time for travel within New Zealand, with people frequently holidaying away from their main medical facilities," Josh Knight, a study author and research fellow at the University of Melbourne in Australia, said in a statement. "This could contribute to delays in both seeking treatment, due to a lack of familiarity with nearby medical facilities, and due to geographic isolation from appropriate medical care in emergency situations."

Josephson said the study was interesting but noted that the effect "is only modest in size."

People can take basic steps to safeguard their health, Josephson noted, including checking they have their medication, eating a healthy diet and not overindulging in alcohol.

"The Greeks said everything in moderation and I don't know that we'll find anything more wise than that over the years," Josephson said.

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