Generation New Era: The UK's new birth cohort study

0:16Hello, welcome to the Naked Scientist podcast, the show that brings you the biggest breakthrough and talks to the major movers and shakers in the worlds of science, technology and medicine. I'm Chris Smith and today we're going to examine a major project that's following the development of children born in the UK in 2026.

0:43A lot of what we know about human society, health and disease has been learned from what are called longitudinal studies. These follow large groups of people over long periods of time to see how trends emerge naturally, and the UK has led the way in this work for nearly a century. The link between smoking and lung cancer was famously detected by Oxford University's Richard Doll, who followed a large group of smoking and non-smoking British doctors for more than 50 years. Britain was also the birthplace of the first lifelong longitudinal studies to recruit newborn babies and follow them for their lives.

1:18In fact, some survivors from the first such study over 80 years ago are still enrolled and sharing their data today. Well now, history is about to be made again, with the first new longitudinal birth cohort study in nearly a quarter of a century. Funded by public investment from UKRI through their Economic and Social Research Council, or ESRC, Generation New Era is the most ambitious effort yet, which aims to recruit over 30 ,000 babies born in the UK this year. They'll be followed through their early years and beyond as they grow up and navigate in a rapidly changing world immersed in AI and social media and confronting a future where many of the things we currently take for granted are no longer given.

2:02Alyssa Goodman from the Centre for Longitudinal Studies at UCL is the co-director. So it's a groundbreaking new study of babies being born across the UK in 2026. We're going to be recruiting participants from the summer onwards and we'll be interviewing families and bringing them into this new study that's going to hopefully follow them across the whole of their lives and learn more about the factors that shape both early life and child development but also life chances across the whole of life. this is not the first time that the uk has done this there's a long history of doing these so called longitudinal or cohort studies isn't there the uk has a unique tradition of national birth cohort studies and of birth cohorts more generally so the first one was created in 1946 just after the second world war and it picked up on the boom the first of the baby boom generation and we've had cohorts following that born in 1958, 1970 and in around the millennium.

3:11So this is one of a long tradition. It's a very exciting opportunity to do a new study that both has some similarities and continuity with the ones from the past so that we can learn about how things have changed but also looking very much to the future and taking advantage of all the novel things that we can do now that we never used to be able to do before. What can you learn from a study like this, where you recruit a group, all born in one particular period, and then follow them up in the way that you're proposing to? A lot about how lives unfold. So one important lens for this is looking at inequalities and how inequalities develop, what their causes are and what the consequences of those things are.

3:57So they're really important studies. They've been very foundational for understanding the importance of early life. So I think we all take it for granted that we understand that childhood and early life can be very formative for things that happen to us and things that we do across the whole of our lives. But these studies have been very instrumental for showing that across so many life domains. So whether that's our cognitive development and our educational outcomes and how that plays out, for example, into the labour market or for our mental health and well-being and how those develop through childhood and what impacts those have, for example, on our relationships or our physical health.

4:38and also they've been very heavily used as health studies so some of the older studies were initiated primarily as medical studies looking at child health and how child health develops and those have been really instrumental especially as they've gotten older for understanding how early conditions and early health lay the foundations for your health in middle age and also ageing. The thing is though, Alyssa, life is changing and the planet is changing and the way we're living our lives are changing so quickly now. Is it not a problem or are you having to actively engineer into the study design the way we learn so that it remains relevant given how fast things are changing?

5:22Because otherwise by the time you get the data from these kids, the environment that they grew up in won't exist anymore. Throughout history and throughout the history of these studies, there's been bursts of rapid technological change. So the Millennium Cohort Study grew up in the internet era, and they were the first generation to have that very significantly through their childhoods. And when they were teenagers, we were very keen to see how they were using social media and so on. That wasn't an issue for previous generations. Probably the 1958 cohort among the ones that we've collected are the ones who experienced things like computerization and digitization at work.

6:03So of course now we're entering the AI era and there's very rapid technological change. We're both seeking to understand how that impacts families and impacts children without really knowing where it's going exactly. So we do our best to future proof the study. We're always keeping on top of scientific developments for how we measure new things, for example, how we're going to measure screen time in the digital environment or engagement with AI. We consult with a lot of experts and we do our best to capture things in as agnostic a way as possible as to what the future scientific questions are going to be that we'll want to look back and ask.

6:47So it's true, we don't know whether the environments that these children will grow up in are going to be the same or different to the generations of the future, but it will capture as good a record as possible of the environments that these children are growing up in. And who are you going to look at and how are you going to get to them? So we're looking to recruit a very large sample. This is the biggest ever of the national birth cohort studies that the UK has run. So we're aiming to recruit 30 ,000 babies. At its core, it's a nationally representative sample. So we're trying to paint a picture of babies born across the whole of the UK.

7:28We have a particular interest in babies who are born to a diversity of families, so we have boosts on ethnic minority status and also low-income families, and we're very, very keen to recruit fathers, whether they live with the baby when the baby's born, or the fairly sizable minority of those who don't live with the baby from the outset. So we're looking to capture all families from around the UK and be as representative as possible. There'll be recruited families who are chosen to take to be invited to take part in the study or receive letters through the letterbox initially asking them to consider taking part.

8:13They'll be able to opt out if they choose. And then we'll be sending interviewers to the homes of the families and conducting surveys, hopefully with as many parents as engaged with the child. so both mother and father we're looking to recruit same-sex parents heterosexual couples all diversities of families and and get as full a picture of their family life as we can. It's going to be a really insightful project isn't it that was Alyssa Goodman and we'll hear a bit more from her later on in the program about what she hopes the study overall is going to show us. First though we're going to find out how this study is going to be conducted and, crucially, who might be taking part.

8:59Pascoe Firon is the co-director of Generation New Era and also an academic based in Cambridge and in London. And he began by telling me how this study is a departure from previous similar projects. The first really big difference is that we're doing it now and we're not relying on data that is now very old. So if we want to understand the causes of children's development now, we have to collect new data, we have to engage new families, etc., who are growing up in these completely different circumstances. The internet didn't exist. Social media didn't exist. All kinds of vaccines that just didn't exist are now available.

9:31And you have many, many different layers where the circumstances have completely transformed, not in 50, 60 years, but even in the last 10, 20 years, radical changes in British society and in technology. The way that we do that is firstly about who we're recruiting and when are we recruiting it. The second is about finding ways to measure a lot of these new emergent phenomena, You know, like trying to capture children's exposure, for example, to digital technologies or their use of or exposure to AI driven technologies in home life or in education, for example. So we have to be kind of smart about how we capitalize on new technological possibilities.

10:07I was just going to say you've got to be quite clever because you've also got to anticipate what's coming down the track. So as this cohort moved through, things that haven't even been invented yet, the study has the power to measure its impact. Yes, exactly. Yeah. So obviously we try to do a lot of horizon scanning, trying to think, OK, what's coming up in the next five, ten years? What do you think? What are you having to plan for? What do you think? Well, the big ones right now are definitely around social media and AI. AI is the most challenging in a way because, you know, we literally were all getting our heads around what kind of an effect that might have on society, on home life and on education in particular.

10:42So that's going to be the toughest. Social media has been around long enough that we do know how to measure the fundamentals quite well, but it is a moving target. so that's also like really interesting and challenging because it keeps evolving and so our measurements have to evolve with it the fundamental thing there is really to have a really big team and to collaborate a lot with as many colleagues who are on the academic side of this and in industry to try our best to be as close to the kind of cutting edge as we possibly can so that you know that that helps to kind of keep us fresh and on uh point you know in relation to things that are coming down quickly.

11:16The important thing to my mind with a study like this is to make sure it captures the general picture and it doesn't just capture one small slice of society. And people often are worried when you recruit people into a study that highly motivated, highly educated people sign up and you miss the people that don't fit those criteria. So how do you or how will you make sure this is comprehensive across the demographic, the social spectrum across the UK, for example, when doing this? How many people are you going to look at? One of the points of this project is it's supposed to represent the UK public and the children growing up in the UK right now.

11:56Represent, i.e. when people learn about, you know, they use the data from the study or they read the papers that we write about it, it's saying something they can rely on about how British society actually is right now. And as you say, if you rely just on people who come all the way to the university or they email and say, I'd love to be involved in this thing, you get a very distorted picture of that. So there's a whole sort of set of technical things that we do to try and deal with that. The biggest one really is that we write to a very large number of people in a kind of systematic way. So we will be trying to recruit 30 ,000 families from across the whole of the UK.

12:32We'll be reaching out to probably about double that because we know not everyone will choose to take part. And we'll be making kind of active efforts to contact them so that it's not just whether they happen to hear about it. We'll be kind of sending out letters. So you know who's having a baby and you're on to them. Yeah, basically, yes, exactly. Yeah, yeah, yeah. And we will really kind of actively offer them the opportunity to take part. Nobody has to take part if they don't want to, of course, but we really go to great lengths to make sure that if they want to take part, they definitely can and they hear about it so that we get a very large proportion of the eligible people taking part.

13:07Do you consider brothers and sisters as well? because that's also quite valuable isn't it because you can see individuals who are different but they're growing up in the same family unit and that can yield valuable insights as well or is that not part of this remit that's a really good question we've talked about that a lot so we don't it's not part of the sort of initial plan for how we engage families children coming into the study may have siblings or they may not we will have twins they're also super interesting Yes, I was going to say, because if you've got a twin, do you end up recruiting both then?

13:40Definitely. So you would do brothers and sisters under those circumstances. Yeah, absolutely. And they're super interesting for so many different reasons, because they're literally born into the world at the same precise moment. And so differences between them are super interesting. They could be to do with their different genes, could be to do with their different experiences, and so on. So they are extremely interesting. And siblings, especially later on in the study, we will be really keen to make sure that they're part of the picture too. So you'll get a snapshot presumably from the family of the demographic, what the parents do, where they live and so on at the start point which is that baby is born and they're recruited into the study.

14:17How do you go forward after that? How often are you going to contact them? How will you collect the data? How do you make sure you can keep in touch with them? Because people go all over the place. The general schedule is that we would tend to visit families about every two years. And not all of that is set in stone at this point, I should say. But for the moment, we're funded for the first three years of the family's lives. And then, you know, hopefully they will continue with more funding and we keep going. So the plan at the moment is we'll see families when the babies are about nine to two, 11 months of age.

14:46And then we'll see them again when they're about three. And that pattern will probably continue roughly for some years after that. In addition to that, we stay in touch with families quite a lot. So we'd like to keep them really appraised of what's going on. So we'll be writing to them and telling them about what we're up to and the fruits of their labours, as it were. And they can also download a smartphone app, which is part of the study. So that's a way in which we can be asking them questions in a sort of little but often kind of way, which is actually a really interesting way to do it, particularly if you're interested in the kind of rapid changes that happen between, say, 10 months and three years, which is a lot of things, then we can ping them with little questions that only take them a few minutes to do once a month or every couple of months and things like that so we can really chart the trajectory.

15:32So we've got a smartphone app and then we've got these slightly more extended contacts where we meet them which tend to be about every two years. Pascoe Fieron on how you operate a study on this sort of scale. The Naked Scientist podcast is produced in association with Spitfire. Cost-effective voice, internet and IP engineering services for UK businesses. Find out how Spitfire can empower your company at spitfire.co.uk.

16:02Music in the programme is sponsored by Epidemic Sound. Perfect music for audio and video productions. This is the Naked Scientist podcast with me, Chris Smith. And today, in partnership with UKRI's Economic and Social Research Council, we are getting the inside track on the first UK-wide longitudinal birth cohort study in over 25 years. Indeed, the last time the UK ran a major birth cohort study was at the turn of the last century. That one was, appropriately enough, dubbed the Millennium Cohort Study, and it was led by Heather Joshi. She told me how it came about. The government decided that the Millennium celebrations should include not only a dome or a bridge about a cohort study and they decided this late 1998 with the aspiration to have a cohort study kind of up and running or up and changing nappies in the year of the millennium of 2000 and it turned out that timing was very very tight so we didn't manage to start the cohort with people born throughout the year 2000.

17:11The oldest cohort member was born in September 2000. Their families were interviewed when the babies were nine months old. Well, many people argue that the new millennium did start in 2001, so you absolutely hit the nail on the head regardless, didn't you? So this was intended really to capture people born around the time of the year 2000 and follow them up. So they're now 25 years old, give or take, aren't they? that group that you've been following. How many have you got? I think we're probably down to about 11 ,000 or 12 ,000. A significant number nonetheless, isn't it? Oh, sure. What did they think mattered that needed to be measured?

17:51Well, there'd been a lot of pressure from the social science and the medical research community to continue the series of birth cohort studies, and there was never any money for it. So the millennium provided a pretext for finding an extra budget. Was it largely run the same way with a big recruitment at birth and then regular follow-ups? Yes it was. It followed in some sense over the model of the cohort studies that had preceded it but it varied in a number of ways some of which are being carried forward into the new study. One feature was that babies were recruited throughout the year rather than in one week, which the previous ones had done.

18:38And the process by which we attempted to get a representation of all families across the country was much more sophisticated than just take all the births in one week, which the previous studies had done. and it was designed to try to make sure that families living in deprived areas were given a higher chance of getting selected and likewise families living in areas where there was a high proportion of ethnic minorities had a higher chance of being selected. And this feature of the sampling frame survives in the new cohort. the ethnic origin of a baby is recorded in health records that we didn't have access to.

19:23So they will have a better representation of ethnic groups than we did. What emerged as you began to follow up these individuals? Are there any standouts or things that you, looking back now a quarter of a century on, think, well, that's quite surprising or that's quite shocking. We thought there would be social inequalities in families living circumstances and in children's progress on various fronts which indeed we did find now that wasn't surprising that was the reason that we were doing it but these social and economic differences it wasn't just a question of rich children and poor children are different there are many ways and in many aspects in which children's development varied.

20:12Their academic progress, their behavioural adjustments when they get into teenage years, their delinquent behaviour, their physical health. And I guess the observation that has emerged as a very important finding of the study is their weight, which is much higher for the current generation or when they were teenagers than previous generations. and the fact that these data had been collected alongside all the information about their family circumstances, this could show that this obesity epidemic, so-called, was much more severe amongst the disadvantaged families than amongst the advantaged families.

20:57And with the sort of normal methods of recording population health statistics, this wouldn't have been clear. alongside the question of obesity weight gain and and the health impacts of that were there any other standouts because one thing that has occurred to me and and my experience working in a hospital as i do and i'm married to a gp is the number of people who now seem to be presenting with mental health problems the context is thought to be exacerbated by social media So I think, yes, and this generation did have worse mental health than the predecessors. Heather Joshi, who led the previous UK longitudinal study for the new millennium.

21:45To Northern Ireland now, which will play a big part in the new study, Generation New Era. The Economic and Social Research Council wanted all four nations to be included in order to paint a representative picture of childhood development across the UK and also to highlight how and where that might differ. Northern Ireland is something of a special case because it's seen a great deal of change, especially off the back of the peace process and the Good Friday Agreement that were introduced to bring an end to the troubled decades that had come before when rival factions were fighting over reunification.

22:17We asked Orla McBride, the lead for Generation New Era in Northern Ireland, to explain. In Northern Ireland, for example, in terms of the population size, it is the smallest UK nation. Northern Ireland has had a difficult time in terms of the troubles, which has been a period of political instability, which has changed over the last number of decades since the Good Friday Belfast Agreement in terms of the peace process. But in Northern Ireland, there are distinct cultural differences. So historically, the community has been quite segregated in terms of education and how communities are planned and how people live their lives.

23:01So it's really important that those differences are understood and explored in terms of how the environment in which young children are growing up and how their parents grew up and their grandparents is influencing family life and their levels of social support, how they work, how they engage in their community today because we know from previous studies that those types of factors surrounding the child and family can influence the outcomes for that child and family over time. When you do the study will a family in Northern Ireland be asked exactly the same things as a family in England or are there regional differences because if there are things that you get at which are a bit special to a given geography it makes sense to tailor the inquiries and the studies to that area a bit so will there be differences or are you going for one comprehensive study everywhere for the first wave of generation new era which we are conducting when the babies are around nine to ten months the vast majority of questions that parents will be asked about their their own lives and the lives of their babies at that age will be standard across the UK.

24:19So these are typical questions around the baby's growth and development, typical milestones, how they're sleeping, feeding, their temperaments, how they bond with their parents, other family members in the household. Those types of standard questions will not only be coming across the UK, but also largely consistent with what has been asked in previous cohort studies in order to allow us to determine how these indicators of growth at this young age in childhood have either changed or remained the same over different and previous generations. but as we move forward a lot of the design of Generation New Era is influenced by public engagement with policy makers and academics in each of the UK nations so it may be as we move forward in the study there may be particular policy relevant areas unique to Northern Ireland for example potentially in terms of maybe education that we may need to drill down into slightly differently than we do in the other UK nations.

25:27Really powerful that you've got that overlap with previous studies so you can do that direct A-B comparison. How do you actually do a study like this though? Because there's going to be mountains of data coming in, you hope, when everyone signs up to take part. Let's cross our fingers. But what happens to that data? How does it get analysed and who does the analysis? You're right. There is a lot of data generated by this type of a study. And particularly Generation New Era is really innovative in its design. So we will be collecting a lot more data than even previous longitudinal cohort studies, such as the Millennium Cohort Study that was conducted in 2000, 2001.

26:10And as a team, we will be producing findings, initial findings from the study when all of the data is in and we've been able to analyse it. But that is just the headline or scraping the surface of the explanatory power of this social science data resource. So the Economic and Social Research Council who are funding the study require us to deposit data. So that's like putting the data into a bank where trusted and trained researchers from across the world can access this data and be able to use that to conduct research projects. So a lot of our trainee researchers, people that are training to do PhDs or postgraduate level training, will use these type of data resources to drill down into very niche areas within the data.

27:07And we do a lot as a team, we do a lot of engagement with academic researchers and policymakers to make them aware of the availability of the data and also the richness of the data. And along with colleagues at the University College London, we do a lot of training as well with researchers as academics in order to help researchers navigate and get the maximum use out of this longitudinal data. It's quite complex to analyse this data and you need to have a certain skill set to be able to do it well and correctly and to ensure that the findings are accurate and are addressing specific policy research questions.

27:48But yes, it's very exciting and the data will be used for many decades to come. Will you also have the potential to get biochemical data? Because obviously there'll be a lot of social data, there'll be other measurements and things and following the children up. But the UK Biobank has been a massive instrument for unlocking new discoveries in how clinical medicine manifests as diseases over years and this strikes me as the most amazing opportunity to get the fine-grained data you're going to collect alongside some biochemicals that we could analyse in the future. So is that going to happen as well?

28:25One of the really exciting things about Generation New Era is it's been conducted at a time when we're really at the cusp of a lot of methodological innovations and the study is really rooted in administrative data possibilities and so we may be able to link participants data once they give us consent to do so so that's that's really exciting as we move forward and at each wave of this study there will be specific consultation as to what is appropriate to collect from young babies and children as they go and develop. All of McBride, Generation New Era's lead for Northern Ireland. So how will we know if this study has been a success?