Global life expectancy has increased dramatically^[1] over the past century, with Australia among the best performing countries.

But during the last two decades, some high-income countries have reported stagnation or even declining life expectancy^[2], particularly the United States^[3] and the United Kingdom^[4].

Could this indicate a broader decline in health advancements in English-speaking countries? Our new study^[5] compared life expectancy between English-speaking countries and against other high-income countries.

We found Australians born between 1930 and 1969 continue to do exceptionally well for life expectancy. But the picture for those under 50 is not so rosy – life expectancy is stagnating for that younger group.

Why measure life expectancy?

Life expectancy is a valuable and widely used measure to examine health trends and patterns over time and compare different places or population groups.

It estimates the average number of years a person would be expected to live. This is calculated using the mortality – or death rates – across different age groups within a specific period. When death rates fall, life expectancy rises, and vice versa.

Life expectancy can tell a story about a population’s overall health. Christian Wiediger/Shutterstock^[6]

Not only does life expectancy tell us about mortality in a population, it is indirectly a measure of overall population health. Most leading causes of death in high-income countries are chronic diseases^[7]. These typically affect the health of a person for multiple years before their death.

Stagnations or reversals in life expectancy can be warning signs^[8] of both longstanding and emerging health problems.

Nobel Prize-winning economist Amartya Sen has also pointed to mortality as a key indicator of economic success and failure^[9]. This makes it a powerful tool for researchers and policymakers.

Thanks to a long and largely standardised tradition of collecting mortality statistics across high-income countries, researchers are able to carry out in-depth, comparative studies. This can help uncover how specific causes of death have contributed to the changes in life expectancy.

What we did

In our study, we analysed mortality trends and patterns in a broader group of English-speaking countries and compared them with other high-income countries. English-speaking countries have shown similarities in recent mortality trends and their causes, such as patterns of drug overdose^[10] and obesity prevalence.

Our analysis focuses on six high-income English-speaking countries: Australia, Canada, Ireland, New Zealand, the UK and US. We compared them with the average in 14 other high-income, low-mortality countries from Western Europe (such as France and Norway), plus Japan. This was the “comparison group”.

We used data from 1970 onwards from well-established, comprehensive sources of high-quality mortality data: the Human Mortality Database^[11] and World Health Organization Mortality Database^[12].

For each English-speaking country and the comparison group, we estimated:

• life expectancy at birth
• partial life expectancy between ages 0 and 50 years
• remaining life expectancy at age 50
• average length of life.

Looking at average length of life helps to compare the mortality of the birth cohorts (people born in the same calendar year) as they age. This measure is the closest way to estimate how long people in different populations actually live, and can be used to assess the differences in survival between populations.

First we looked at how age and causes of death were contributing to a gap between English-speaking countries and the comparison group. Then we compared the average length of life of different birth cohorts.

What we found

In the pre-COVID period, both men and women in Australia had a higher life expectancy at birth, compared to the non-English speaking comparison group (the average between those 14 countries). This was also true for men in Ireland, New Zealand and Canada. In the UK and US, however, life expectancy at birth was lower for both men and women, compared to the non-English speaking group.

But the most striking finding was the difference in mortality for those under 50 in English-speaking versus non-English speaking countries.

Relatively high death rates for those under 50 dragged the overall life expectancy at birth down for each English-speaking country, including Australia. Suicides and drug or alcohol-related deaths were the main reason for these trends.

But over age 50, Australia performs exceptionally well in life expectancy for both men and women. Australians born in the 1930s-60s are likely to live longer than those in the non-English speaking comparison group and all other English-speaking countries. But Australians born in the 1970s onwards had lower life expectancy than the comparison group.

This means overall, life expectancy at birth in Australia is higher than the average for the non-English group. But when you break it down by age, the results show a clear distinction in life expectancy according to when you were born.

For example, in 2017-19 , male life expectancy between ages 0 and 50 years was 0.3 years lower in Australia compared to the average for the non-English group, while remaining life expectancy at age 50 was 1.45 years higher.

What this means

Our study shows a worrying trend for people born from the 1970s onwards. This is true in all English-speaking countries, even before accounting for the negative impacts of the COVID pandemic in places like the UK and US.

In Australia, the results point to significant generational differences in life expectancy compared to other high-income countries. If the relatively high mortality rates of Australians born from the 1970s onwards continue into the future, then the gains in Australian life expectancy will likely slow. Our status as having one of the highest life expectancies of any country will diminish.

Our research aimed to examine trends and potential causes of stagnating life expectancy, rather than make policy recommendations.

But the results suggest real improvement could come through measures that reduce inequality and structural disadvantages that lead to poor health outcomes, such as improving access to education and security of employment and housing, supporting mental health and drug-related safety, and addressing diseases like obesity and diabetes.

References

1. ^{^} Global life expectancy has increased dramatically (population.un.org)
2. ^{^} stagnation or even declining life expectancy (doi.org)
3. ^{^} the United States (jamanetwork.com)
4. ^{^} the United Kingdom (www.thelancet.com)
5. ^{^} new study (academic.oup.com)
6. ^{^} Christian Wiediger/Shutterstock (unsplash.com)
7. ^{^} chronic diseases (www.aihw.gov.au)
8. ^{^} warning signs (www.bmj.com)
9. ^{^} key indicator of economic success and failure (www.jstor.org)
10. ^{^} drug overdose (onlinelibrary.wiley.com)
11. ^{^} the Human Mortality Database (www.mortality.org)
12. ^{^} World Health Organization Mortality Database (www.who.int)