Excess mortality at Christmas due to cardiovascular disease in the HUNT study prospective population-based cohort in
Trine Moholdt1,2, Clifford Afoakwah3, Paul Scuffham3,4
1Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway.
Insights
The Christmas holiday period sees a significant increase in deaths, particularly cardiovascular-related ones, in Central Norway. This study identified December 25th-27th as the deadliest period, highlighting seasonal mortality risks.
Area of Science:
- Public Health
- Epidemiology
- Gerontology
Background:
- Winter and holiday periods are known to increase mortality risk.
- Few studies have prospectively examined mortality patterns during Christmas holidays within a profiled cohort.
- This research investigates specific mortality characteristics during the Christmas period.
Purpose of the Study:
- To determine the specific characteristics of mortality occurring during the Christmas holidays.
- To analyze excess all-cause and cause-specific deaths during winter and the Christmas period.
- To examine long-term mortality patterns in a Norwegian population cohort.
Main Methods:
- Utilized data from the Trøndelag Health (HUNT) Study, a prospective population-based cohort in Central Norway.
- Included baseline profiling of 39,273 men and 40,353 women (aged 48±18 and 50±18 years) from 1984-1986.
- Examined long-term mortality patterns over 33.5 years for overall winter and Christmas holiday periods.
Main Results:
- Overall winter (Dec-Feb) had 1540 excess all-cause deaths and 735 excess cardiovascular deaths compared to summer.
- December 25th-27th was the deadliest 3-day period, with significant excess all-cause and cardiovascular deaths.
- All-cause mortality incidence rate ratio increased by 1.22 in men and 1.17 in women during Christmas/New Year holidays compared to early December.
Conclusions:
- The deadliest time in Central Norway is the Christmas holiday period, marked by excess winter deaths.
- Cardiovascular-related mortality patterns change significantly during Christmas, unlike cancer mortality.
- Further research is warranted to confirm findings in other populations and explore preventability of excess deaths.
Background:
Although it is known that winter inclusive of the Christmas holiday period is associated with an increased risk of dying compared to other times of the year, very few studies have specifically examined this phenomenon within a population cohort subject to baseline profiling and prospective follow-up. In such a cohort, we sought to determine the specific characteristics of mortality occuring during the Christmas holidays.
Methods:
Baseline profiling and outcome data were derived from a prospective population-based cohort with longitudinal follow-up in Central Norway - the Trøndelag Health (HUNT) Study. From 1984 to 1986, 88% of the target population comprising 39,273 men and 40,353 women aged 48 ± 18 and 50 ± 18 years, respectively, were profiled. We examined the long-term pattern of mortality to determine the number of excess (all-cause and cause-specific) deaths that occurred during winter overall and, more specifically, the Christmas holidays.
Results:
During 33.5 (IQR 17.1-34.4) years follow-up, 19,879 (50.7%) men and 19,316 (49.3%) women died at age-adjusted rate of 5.3 and 4.6 deaths per 1000/annum, respectively. Overall, 1540 (95% CI 43-45 deaths/season) more all-cause deaths occurred in winter (December to February) versus summer (June to August), with 735 (95% CI 20-22 deaths per season) of these cardiovascular-related. December 25th-27th was the deadliest 3-day period of the year; being associated with 138 (95% CI 96-147) and 102 (95% CI 72-132) excess all-cause and cardiovascular-related deaths, respectively. Accordingly, compared to 1st-21st December (equivalent winter conditions), the incidence rate ratio of all-cause mortality increased to 1.22 (95% CI 1.16-1.27) and 1.17 (95% 1.11-1.22) in men and women, respectively, during the next 21 days (Christmas/New Year holidays). All observed differences were highly significant (P < 0.001). A less pronounced pattern of mortality due to respiratory illnesses (but not cancer) was also observed.
Conclusion:
Beyond a broader pattern of seasonally-linked mortality characterised by excess winter deaths, the deadliest time of year in Central Norway coincides with the Christmas holidays. During this time, the pattern and frequency of cardiovascular-related mortality changes markedly; contrasting with a more stable pattern of cancer-related mortality. Pending confirmation in other populations and climates, further research to determine if these excess deaths are preventable is warranted.
