University of Melbourne researchers have found an increase in heart attacks around the festive period may be due to more difficult access to hospitals, combined with stress, an excess of alcohol and a fatty diet.
Previous research from the USA has established that the Christmas holidays are related to more heart attacks, however, it was thought it could be due to the season - winter - when mortality rates are at their highest.
To find out, University of Melbourne researchers analysed 25 years' of death records of heart attacks between Christmas and the first week of January, during summer in the southern hemisphere.
The research, published today, in the Journal of the American Heart Association, revealed a 4.2 per cent increase in heart-related deaths occurring out of hospital during the Christmas period in New Zealand.
And victims were typically younger. The average age of cardiac death was 76.2 years during the Christmas period compared with 77.1 years at other times of the year.
Lead author and researcher at the Centre for Health Policy at the University of Melbourne, Josh Knight, said by using data from a country where Christmas occurs in the height of summer, he was able to separate any "holiday effect" from the "winter effect".
Knight said that there is a need to understand whether restricted access to healthcare facilities might be combining with other risk factors such as emotional stress, changes in diet, alcohol consumption result in the spike in cardiac deaths.
He suggested patients might also hold back in seeking medical care during the holiday season.
"The Christmas holiday period is a common time for travel within New Zealand, with people frequently holidaying away from their main medical facilities," he said.
"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."
Another explanation may have to do with a terminally ill patients' will to live and hold off death for a day that is important to them.
"The ability of individuals to modify their date of death based on dates of significance has been both confirmed and refuted in other studies, however it remains a possible explanation for this holiday effect," Mr Knight said.