Marked decline of sudden mass fatality events in New Zealand 1900 to 2015: the basic epidemiology

The rise and fall of excess winter mortality in New Zealand from 1876 to 2020

Excess 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.

Descriptive Epidemiology of New Zealand's Highest Mortality Earthquake: Hawke's Bay in 1931

In this study we aimed to produce the first detailed analysis of the epidemiology of the severe injury and mortality impacts of the 1931 Hawke's Bay earthquake in New Zealand (NZ). This involved the compilation and analysis of archival data (hospitalisations and deaths) including the examination of 324 death certificates. We found that there were 662 people for whom some hospitalisation data were available at four weeks post-earthquake: 54% were still in hospital, 4% were still classified as "serious", and 5% had died (n = 28). Our classification of death certificate data indicated 256 earthquake-attributable deaths and for another five deaths the earthquake was estimated to have played an indirect role. There were 15 buildings associated with three or more deaths each (accounting for 58% of deaths with a known location). Many of these buildings were multi-storey and involved unreinforced masonry - with some of this falling into the street and killing people there (19% of deaths). In contrast, deaths in homes, which were typically of wood construction and single stories, comprised only 3% of deaths. In conclusion, this earthquake had a relatively high injury impact that appears partly related to the lack of regulations for building construction that would mitigate earthquake-related risk. Such regulations continue to be of relevance for New Zealand and for other countries in earthquake zones.