New Zealand mortality at older ages improved in 2024. Normal trends have resumed after Covid-19. But not all is well.
Previous posts have shown during the pandemic, New Zealand’s mortality was extraordinarily light, especially compared to the experience of many other countries. However, the rate at which mortality improves has been stalling in many countries, including New Zealand. So the question for 2024 was whether mortality would resume its pre-pandemic gradual improvement.
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What happened in 2024?
Death rates (also called mortality rates) count the number of deaths in a year at a specific age as a proportion of the number of people alive at that age.
If death rates fall over time, mortality is improving, which means people are living longer lives.
This mortality improvement has been playing out in New Zealand with a steady fall in mortality rates over decades, with annual ups and downs due to seasonal impacts and random variations. This means average lifespans steadily improve.
This blog has been tracking the mortality of the older age population in New Zealand. The chart below updates the history of death rates from 1994 to 2024. The steady fall over decades can be seen, together with the fluctuations where death rates are highest, at the oldest ages.
The saving of lives by closing borders in the first wave of the pandemic can be seen by the sharp improvements in 2020-21. The blip upwards in 2022 shows some mortality catch-up, then mortality improved at most ages in 2023. In 2024, the chart shows a continued downward trend, which suggests normal trends have been resumed.
As in previous posts, it’s useful to see the changes by indexing changes in death rates over time to a specific period. The index period chosen here is the average of 2015-17; before the pandemic and averaging over three years to smooth out any oddities in a single year. The choice of years is simply to compare later experience to a period before the pandemic.
Below is the index chart updated to 2024, showing as the brown line.
The improvement in 2024 is clearly seen by the brown line being below the 2023 pink dots for all but one age-group, and below the 2015-17 index at all ages over 50. This means mortality is at least back to where it was before the pandemic, with the biggest improvements since 2015-17 at ages 65-89.
All good then?
As previous posts have shown, mortality rates improved at a slower pace in 2010-2020 compared to 2000-2010. This has led to less optimistic forecasts of long people might live in future, although it is still expected that average lifespans increase for each generation. The slowdown was not unexpected and happened in other countries.
One explanation for this is seen in a study* of 20 European countries, which compared the improvement in average period life expectancy (a summary measure of death rates) over 1990–2011 and 2011–19. In all of these countries except for Norway, the rate of improvement was lower in the second period than the first. The main contributors to improvement in the first period were fewer deaths from cardiovascular diseases (CVD) and neoplasms, but deaths from CVD were the primary driver of slowing improvements during 2011–19. Further,
“countries with the greatest slowdown in life expectancy improvements after 2011 went on to have some of the largest decreases in life expectancy in the Covid-19 years 2019–21.“
This suggests that the best way to achieve continued improvements in health and lifespans is to sustain population health measures – like encouragement to better diets and more activity – over many years, and across the whole population. This is surely good sense on a personal level as well as a reminder for government that population health measures need to continue through financial crises and pandemics.
A major comparison of mortality outcomes in 31 high-income countries** ranks New Zealand poorly with a slow rate of mortality improvement across the population over the years 2000-2019, while giving New Zealand top ranking for the lowest excess mortality during the Covid-19 years of 2020-2023.
What does this all mean for the future?
Of particular concern highlighted by the study of high-income countries is the worsening mortality in New Zealand at younger ages, not usually covered by this blog – around age 30. If mortality is improving, even slowly by international standards, that still means that lifespans are expected to keep lengthening. But mortality going backwards is a huge red flag for the worsening health of the nation, let alone the human cost of early deaths.
Delving into data for young mortality in New Zealand shows the long-term trend of improvement has been shaken up in the last 15 years. The charts below show a linear trend on death rates for age groups between ages 15 and 39 since 2010. We want to see lines going down as that means mortality is improving, but instead we see:
- Lines going up, worsening mortality, for women aged 25-29 and men aged 30-34.
- Fairly flat lines, mortality treading water, for women aged 15-24 and men aged 20-29.
The impact on these generations for average lifespans remains to be seen as mortality at older ages in future may improve significantly. Life expectancy measures mute the force of what is happening now at these specific ages.
This means further analysis should be very granular on cause of death, and variation across the population at each age group. However, New Zealand has a small population and death rates are so low at these ages that such detailed analysis is unlikely to come to firm conclusions. For example, in 2024, there were 37,722 deaths, of which fewer than 240 were from the worsening age groups (81 women aged 25-29 and 156 men aged 30-34).
We can learn from other countries where more detailed analysis is possible, although the causes of any trends may not apply to the same extent, or operate in the same way in New Zealand. And even now, even in data-rich countries, there are many proposed explanations for recent higher-than-expected all-cause mortality. A recent scoping review*** found the most commonly proposed explanations, which need further analysis to confirm and quantify, include:
“continued significant mortality from Covid-19 itself; adverse longer-term effects of SARS-CoV-2 infection (including higher mortality risk); the negative impact of the pandemic on quality of, and access to, healthcare; and wider societal effects such as social isolation, increased poverty and health-harming behavioural responses. Non-Covid explanations that were suggested included extreme weather events, and political and/or societal factors such as funding cuts, drug use, social vulnerability and increased poverty levels.“
Many or all of these will resonate in New Zealand today. Despite adding the after-effects of Covid-19 and the likely increasing impact of extreme weather events, explanations for increasing mortality still include what has been known for many years about determinants for healthy long lives. So, yes, more research will be watched with interest, but that should not be used as an excuse to avoid ongoing sustained efforts – across the population but especially for younger people – to improve diets, activity levels and living conditions.
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*Steel, Nicholas et al (2025). “Changing life expectancy in European countries 1990–2021: a subanalysis of causes and risk factors from the Global Burden of Disease Study 2021”
The Lancet Public Health Online first February 18, 2025
** Dowd, J.B., et al. (2024). “Progress Stalled? The Uncertain Future of Mortality in High-Income Countries.” Population and Development Review.
https://doi.org/10.1111/padr.12687
*** Scott, F. et al. (2025). “Explanations for higher-than-expected all-cause mortality from April 2021: A scoping review.”Public Health, Volume 238, 2025,Pages 73-82
https://doi.org/10.1016/j.puhe.2024.10.010