How has life expectancy changed after the pandemic?

Wednesday 5th Apr 2023, 12.30pm

Demographers (researchers who study the statistics of human populations) look at factors such as birth rates, death rates, migration and life expectancy. But what exactly is meant by the term ‘life expectancy’? How is it calculated, and how has it changed after the pandemic? We speak to Prof Jennifer Dowd from the Leverhulme Centre for Demographic Science to find out.

Find out more about Jenn’s work in our video “Demography: Understanding Our World“.

Read Transcript

Emily Elias: Depending on where you live, your gender, income, life expectancy can vary. Demographers are keen to look at all these trends, but when a pandemic hits, well, that’s when the data gets a little bit more interesting.

On this episode of the Oxford Sparks Big Questions Podcast, We’re asking, “How has life expectancy changed after the pandemic?”

Hello, I’m Emily Elias, and this is the show where we seek out the brightest minds at the University of Oxford and we ask them the big questions. And for this one, we have found a researcher who loves to crunch the numbers surrounding life and death.

Jennifer Dowd: My name is Jennifer Dowd and I’m a Professor of Demography and Population Health at the University of Oxford.

Emily: You’re also looking at life expectancy, right?

Jennifer: Yes. Demographers like to count people in lots of different ways, but especially births and deaths and people moving. So calculating life expectancy and mortality is one of our favourite things, quite strangely.

Emily: Just to make sure that we’re on the same page, when you say life expectancy, what exactly are we talking about?

Jennifer: I guess the first thing to say is, despite the name, it’s not a prediction of the lifespan for any actual baby born today. Even though we often say life expectancy at birth. I t’s really for a pretend new-born, if you want to think of it that way.

And it’s really meant to capture a snapshot of what’s going on with mortality in the current year, and it’s one of the best measures we have to do that, and we calculate it in kind of a strange way. Again, we take the mortality rates in the current year for every single age, and we pretend that there’s a baby born this year that goes through their entire life, with exactly those mortality rates at each age.

So their chances of dying, you know, when they’re very young or small, but as they get older, they kind of accumulate. And then we say, what would be the average age of death of someone who went through their whole life with, kind of, the probabilities of death that we see in this single year?

And that’s how we come up with life expectancy in any given year. So it’s really for this, kind of, pretend person that’s running through, kind of, a simulation. So you can almost imagine going through a video game, but we’ve programmed what your chances of dying at each level are. And then we say, you know, what would be the average time that a player would survive in this video game?

So it’s just like that. We call it a synthetic cohort. It’s, kind of, putting people through this pretend lifespan where the age, the mortality rates are exactly as they are in the current year and don’t change whatsoever.

Emily: And so life expectancy then is different in different countries because of different factors that they’re living through, different levels that they have to contend with?

Jennifer: Yeah, exactly. So there’s, you know, more hazards in different countries, and that’s been true throughout history too. So the really good thing about life expectancy is it does help us summarise in one number the mortality conditions that we can compare then across countries and across times.

So, you know, in countries or in historical periods where there was a lot more death at early ages, under five mortality used to be extremely; high infant mortality.

That means a lot of people don’t get through that very first level of the video game, and average life expectancy is much, much lower. And so that was true, prior to the 1800s, probably for most of human history, life expectancy hovered in the thirties to forties and didn’t change very much, even for thousands of years.

It definitely, you know, went up and down a bit with famines and other shocks but, you know, mostly it was hovering in that range because there was tons of mortality amongst babies and very early in life. And then, you know, some people who made it through childhood did live longer than 30 or 40. It’s not that no one lived past 40, it’s that it averaged out to about 30 or 40.

Because so many people died at very young ages, and that was also true, you know, until recent decades and still in some parts of the world, especially the continent of Africa. That, I think, in 1950s still had a life expectancy in the thirties while we had countries at the same time, in the 1950s, like Norway, that had a life expectancy already of 72.

So there were huge inequalities, even in 1950, that have converged a bit since then because we’ve seen great improvements in things like child and infant mortality around the world.

Emily: Okay, so let’s jump in our time machine then and go a bit forward to pre-pandemic. As a demographer, what were you seeing in terms of life expectancy in the UK and the US?

Jennifer: If you take a long view for the last 200 years, the progress has just been remarkable. We can expect to live twice as long as our ancestors, which is really amazing when you think about it. But there have been some signs of trouble on the horizon, especially in the US in about the last 20 years, where life expectancy improvements had really slowed down and even gone a bit backwards in the US. From 2014 to 2017, they saw declines, which is really unusual.

You know, in the last couple hundred years, we’ve seen this steady march of improvements of life expectancy except for, you know, the 1918 flu and the two world wars. So to see this unexpected decline in the US just, kind of, come out of nowhere was really startling to a lot of people. And the UK is doing better in absolute terms than the US.

Around 81 years compared to 79 or 78 in the US. But they also have started to see a stagnation and a slowdown in improvements since about 2011. And it’s also been noticeable in the UK that they’re falling behind on a relative basis compared to the European neighbours. So, you know, there seems to be something going on, whether that’s a mortality Brexit or the results of austerity measures since 2008.

There’s a lot of hypotheses, but we’re, kind of, lacking firm evidence on exactly what’s going on in the UK.

Emily: Do you have any theories as to why we’re seeing this stagnation in life expectancy?

Jennifer: Yeah, it’s been the subject of a lot of head-scratching and scholarly research in the US. There have been some papers going back several years by Anne Case and Angus Deaton that first highlighted this rising mortality of people more in midlife. So we often obviously think about death at older ages, driving life expectancy, but we’ve actually seen increases in mortality that are very unusual, more in the 45 to 64 year old range in the US, and they attributed this to what they called ‘deaths of despair’, due to a constellation of three different causes; alcohol related deaths, drug overdose deaths, and suicide.

And that, you know, was a very powerful paper that kicked off a lot of interest and debate. And so I’d say it’s not quite, you know, as need of a story that it’s all driven by deaths of despair or it’s not true that all of these causes of death go together.

It really does seem that the drug overdose epidemic is a very specific thing that’s happened in the last 20 years in the US and maybe not as closely related to alcohol related deaths and suicide. It’s really just at staggering levels that you don’t see in any other really high income country, except Scotland, I’ll say Scotland, is very small.

And so you don’t see it overall in the UK or England and Wales. But Scotland does also currently have quite a high level of drug overdose deaths. And I’ll just say the other hypotheses about the US that, kind of, provide an additional explanation are that we’ve really seen a slowdown in improvements due to cardiovascular disease.

And you know, just for many, many decades, we saw cardiovascular disease deaths, which is one of the major causes of death decline, decline, decline very rapidly. And part of that was due to lower rates of smoking. That take 40 years to play out. So when smoking rates decline, there’s this lagged effect.

So we had that, we had new treatments for high cholesterol, high blood pressure, all sorts of other medical advancements. But that has slowed down a lot. And so the question is, have we reached the limit of the improvements that we can make from cardiovascular disease or are we starting to see countervailing effects from something like the obesity epidemic? Which is particularly severe in the United States and has now been going on for many decades.

Emily: What about the pandemic? I mean obviously that data is very new and interesting in its own right, but what have we seen happen when you look at that period of time?

Jennifer: Well, I’m glad you asked because, no, I’m very interested in studying the pandemic and it has been quite shocking, I think. Yeah, I’m thinking a lot about it because it was just three years ago, kind of, this week that a lot of the pandemic stuff started unfolding and I think one of the early questions was exactly how fatal is this new disease, because a lot depended on that.

If it really was just a bad flu, you know, it probably wouldn’t merit all of the lockdown measures and all the other extreme prevention that happened and we really, you know, didn’t have a handle on that very early on. But after, you know, studying the mortality impact of the pandemic for the last two to three years, I can safely say that it was nothing like the flu. Unfortunately, we saw very large drops in life expectancy across most of the countries that we were able to study, which to be fair, was, kind of, about 30 higher income countries in Europe, also the US and Chile, because calculating life expectancy does require quite good mortality data that’s broken down by age and sex in, sort of, a granular way.

So not all countries have as good a data that’s being released as quickly in the era of COVID, but for the countries we looked at, so that’s most of Europe and the US, you know, almost all countries lost some life expectancy. In 2020 compared to 2019, not surprising, the US was one of the hardest hit countries losing almost two years of life expectancy in 2020, whereas the UK, it was closer to one year, about 11 months total.

And then looking at 2021 was interesting because we know the vaccines rolled out in early 2021. So we might have thought that this would be a better year, but in fact we also saw these new variants that were much more transmissible. So we actually had way more infections than we’d seen in 2020 around the world.

So 2021 really was a mixed bag in that respect. And the US actually did worse in 2021 compared to 2020, which is saying a lot because 2020 was pretty bad. England and Wales actually bounced back a bit in 2021, gaining back a couple months of that life expectancy. And then there were a lot of countries, some of the Nordic countries that got back to almost where they were in 2019.

But we also were able to, kind of, forecast what would these country’s life expectancies have been in the absence of the pandemic, if they just continued previous trends and there was no country that achieved where we would expect their life expectancy to have been in 2021 without the pandemic. So, pretty obvious that these were really big hits to life expectancy.

And in fact, we compared these life expectancy drops to other historical periods and for most European countries, we had not seen life expectancy drops of this magnitude since World War II, which is, yeah, quite shocking to me. We’ve had many bad flu seasons, you know, in between and it just looked nothing like COVID.

COVID was very different.

Emily: A bit of a downer, Jen, I’m not going to lie. Is there anything in what you’ve been looking at that is a reason to be cheerful and optimistic about the future? Let’s try end this on an up-note.

Jennifer: I should say I’m definitely an optimist overall. So I can give you some good news I think.

I think one optimistic thing about life expectancy is that we’ve consistently been dead wrong when we guess that there’s a limit to life expectancy. And this has been an interesting phenomenon that demographers have watched for decades now. There’s often actual official bodies like the UN that make some, kind of, prediction that this is the maximum life expectancy that a country could reach, and we continue to break that left and right.

So we have not slowed down in what life expectancies seem to be possible. Again, this is at the country level and not individual longevity or lifespans. So I think that’s a really exciting and optimistic point to remember is that we’ve made so much progress in the last 200 years, and that progress, at least as far as what the maximum life expectancy is, does not seem to be slowing down or changing.

We keep surprising even ourselves, the people who study human mortality. So despite all the scary and uncertain things on the horizon, I think when you look at the long scope of demographic history, our progress on mortality has been extraordinary, so I really think we can keep going on that.

Emily: This podcast was brought to you by Oxford Sparks from the University of Oxford, with music by John Lyons, and a special thanks to Jennifer Dowd. Tell us what you think about this podcast, you can find us on social media. We are @OxfordSparks. We have a website,

And if you’ve got a big question, we’d love to get you a big answer, get in touch.

I’m Emily Elias. Bye for now.


Transcribed by UK Transcription.

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