Abstract
AbstractExcess winter mortality (EWM) has been used as a measure of how well populations and policy moderate the health effects of cold weather. We aimed to investigate long-term changes in the EWM of Aotearoa New Zealand (NZ), and potential drivers of change, and to test for structural breaks in trends. We calculated NZ EWM indices from 1876 (4,698 deaths) to 2020 (33,310 deaths), total and by age-group and sex, comparing deaths from June to September (the coldest months) to deaths from February to May and October to January. The mean age and sex-standardised EWM Index (EWMI) for the full study period, excluding 1918, was 1.22. However, mean EWMI increased from 1.20 for 1886 to 1917, to 1.34 for the 1920s, then reduced over time to 1.14 in the 2010s, with excess winter deaths averaging 4.5% of annual deaths (1,450 deaths per year) in the 2010s, compared to 7.9% in the 1920s. Children under 5 years transitioned from a summer to winter excess between 1886 and 1911. Otherwise, the EWMI age-distribution was J-shaped in all time periods. Structural break testing showed the 1918 influenza pandemic strain had a significant impact on trends in winter and non-winter mortality and winter excess for subsequent decades. It was not possible to attribute the post-1918 reduction in EWM to any single factor among improved living standards, reduced severe respiratory infections, or climate change.
Funder
Health Research Council of New Zealand
University of Otago
Publisher
Springer Science and Business Media LLC
Subject
Health, Toxicology and Mutagenesis,Atmospheric Science,Ecology
Reference53 articles.
1. Annual Report 18/19. (2019) Energy Efficiency and Conservation Authority. https://www.eeca.govt.nz/assets/EECA-Resources/Corporate-documents/EECA-Full-Annual-Report-2018-19.pdf. Accessed 26 July 2023
2. Annual Report 2017/18. (2018) Energy Efficiency and Conservation Authority. https://www.eeca.govt.nz/assets/EECA-Resources/Corporate-documents/EECA-Annual-Report-2017-18.pdf. Accessed 26 July 2023
3. Annual Report: 1 July 2019 - 30 June 2020. (2020) Te Tari Tiaki Pūngao: Energy Efficiency and Conservation Authority. https://www.eeca.govt.nz/assets/EECA-Resources/Corporate-documents/EECA-Annual-Report-2019-20.pdf. Accessed 25 July 2023
4. Appendix 1: The history of immunisation in New Zealand. (2020) Ministry of Health. https://www.health.govt.nz/our-work/immunisation-handbook-2020/appendix-1-history-immunisation-new-zealand. Accessed 22 June 2022
5. Baker MG, Telfar Barnard L, Kvalsvig A, Verrall A, Zhang J, Keall M, Wilson N, Wall T, Howden-Chapman P (2012) Increasing incidence of serious infectious diseases and inequalities in New Zealand: a national epidemiological study. Lancet 379(9821):1112–1119. https://doi.org/10.1016/S0140-6736(11)61780-7