People are more vulnerable to suffer a heart attack during Christmas than any other time of the year due to the ‘Christmas Holiday effect.’ According to previous research, winter was the probable cause of it but a new study just ruled out that theory since it was made using data from a country that celebrates Christmas during summer.

There are more heart-attack-related deaths during the holidays and people who die during the season are younger compared to people that also died from a heart attack but during any other time of the year, according to the new study. The Christmas holiday effect was first described in the U.S., where it was discovered that there were spikes in deaths from natural causes at both Christmas and New Year’s Day.

There is a spike in heart-related mortality rates, but the cause of the phenomenon is not clear yet.

The study found that the seasonal phenomenon could be due to delaying getting medical attention because people are visiting relatives in unfamiliar areas or displacement of death, which is people’s ability to modify their date of death based on relevant dates.

Other causes that could increase the risk of dying of a heart attack during Christmas are the emotional stress associated with the season and changes in the diet and alcohol consumption, but researchers could not determine what is exactly behind the higher risk of having a heart attack during Christmas time.

Northern vs. Southern hemisphere Christmas holiday

University of Melbourne researchers worked with data from New Zealand to discover if winter could explain the Christmas holiday effect. In the United States, Christmas time happens during winter while in New Zealand, it happens during summer. The paper was published in the Journal of the American Heart Association on December 22 and shows the results of the analysis of 26 years of data.

Researchers considered Christmas time the period from December 25 to January 7. The study compared death certificates from those days to the two weeks before (December 11-24) and the two weeks after (January 8-21) the Christmas period to minimize the established impact of seasonality and the “all non-Christmas” periods.

The New Zealand Ministry of Health, along with the Australian National Health and Medical Research Council provided data regarding cardiac mortality during Christmas in the country. The information included death records from 1988 to 2013 and classified deaths during the season into cardiac and non-cardiac.

The data showed that there were around 738 thousand deaths: 541,300 were not related to cardiac disease while 197,109 deaths were linked to cardiac mortality. Among the cardiac death numbers, 95,791 people did not die in a medical facility compared to 101,318 heart-attack-related deaths that happened in a medical facility.

The results showed that 4.2 percent more people died from a cardiac-related cause outside of a hospital during Christmas time compared to other seasonal trends. The results were similar to previous studies that linked to higher cardiac-related death to Christmas in the Northern Hemisphere, but the new survey managed to separate the winter effect from the Christmas holiday effect.

Regarding age, the study found that people died at least a year younger during the holiday season than in any other period. The average of cardiac death was 76.2 years during the Christmas season while in other times of the year, people suffering heart attacks were 77.1 years-old.

Different causes could explain why people have higher risk to have a heart attack during Christmas but scientists have failed to determine which one

When analyzing New Zealand data, researchers found that people often travels away from their primary health centers to visit relatives. This fact could contribute to a delay when seeking medical help due to lack of familiarity with nearby medical facilities and geographical isolation since rural areas often get appropriate medical care in emergencies.

Results comparing data from the two weeks before and after Christmas time considered in the study shows that this could be indeed a factor behind higher chances to suffer a heart attack during Christmas.

Another strong argument is displacement of death, both hastening, and postponement of death for reasons associated with the holiday period. Although individuals are less likely to control heart attacks directly, the results suggest that elevated rates of heart attacks during the season could be due to displacement of death.

“The hastening or delaying of mortality would be expected to create a displacement effect in which a local peak is developed on or around dates of significance, leading to decreases in events surrounding the period in a compensatory manner,” the study says.

There are other possible causes to explain the Christmas holiday effect, including the fat-rich diets consumed during the season and the increased alcohol intake. 

Still, the new study states that inappropriate delay in seeking medical attention and displacement of death are the most supported theories to explain the higher vulnerability to heart attacks during Christmas time.

Source: Journal of the American Heart Association