Revisiting the "Christmas Holiday Effect" in the Southern Hemisphere

Abstract

Background--A "Christmas holiday effect" showing elevated cardiovascular mortality over the Christmas holidays (December 25 to January 7) was demonstrated previously in study from the United States. To separate the effect of seasonality from any holiday effect, a matching analysis was conducted for New Zealand, where the Christmas holiday period falls within the summer season. Methods and Results--New Zealand mortality data for a 25-year period (1988-2013) was analyzed based on the same methodology used in the previous study. Locally weighted smoothing was used to calculate an "expected" number of deaths for each day of the year. The expected value was compared with the actual number of deat..