Intergenerational Impact

In the early 90s, a pioneering health study aimed to sign up every pregnant mother in Bristol and the former county of Avon. Almost 35 years later, findings from the Children of the 90s study has saved thousands of lives.

Nonesuch meets the scientists behind the breakthroughs, and the participants who volunteer their vital data. 

Melanie Davis first found out about Children of the 90s at an antenatal appointment in St Michael’s Hospital, Bristol. ‘There was a lady in the corridor with a clipboard,’ she says. ‘She stopped me and asked if I’d be interested in participating in a study of pregnant women, which would follow up on the health of their babies.’

The researcher explained that it would involve completing questionnaires, attending clinical appointments and providing medical samples, which would be used for research into infant health. Melanie signed up on the spot – joining more than 14,500 expectant mothers throughout Bristol and Avon in one of the most ambitious birth cohort studies ever undertaken.

‘I thought it would carry on during the pregnancy, and for a year or two of my baby’s life,’ she says. ‘I had absolutely no idea that some 34 years later, it would still be going. Three generations of us are involved now. My daughter has two sons, and we’re all part of it.’

The study’s longevity comes as less of a surprise to its founder. Jean Golding OBE (DSc 1994, Hon LLD 2013) (pictured above and below) is Emeritus Professor of Paediatrics and Perinatal Epidemiology, and remains active in child health research at the age of 85. She says: ‘When I set up Children of the 90s, I told people it would last seven years, but I knew I wanted it to go on longer than that. When its success became obvious, I quietly added a zero to the end, so seven became 70.’

Almost halfway along that journey, Children of the 90s (known to academics as the Avon Longitudinal Study of Parents and Children, or ALSPAC) has grown into a unique treasury of social, biological and behavioural data.

The number of participants has swelled to nearly 28,000, comprising the original mothers, more than 3,000 fathers, their children, and a growing cohort of grandchildren – the Children of the Children of the 90s.

Together, they have contributed over a million pieces of data over the course of their lives: not just survey responses, but also biological samples including placentas, milk teeth, nail clippings, blood and hair. Academics from all over the world have based vital work on this information.

To date, it has informed more than 3,000 research papers, covering an astonishing range of health questions, from the safest sleeping position for babies in the crib to the effects of internet use on children’s mental health. Jean credits Children of the 90s with saving tens of thousands of lives. And the breakthroughs are set to continue: in March 2025, a £5.2 million award from the Medical Research Council, Wellcome and the University of Bristol provided funding for the next five years.

A complicated birth

The study’s origins go back to a World Health Organization conference in 1985, when Jean joined representatives of other European countries in Copenhagen. She explains: ‘We asked the question, how can we identify the major health problems of children in Europe, so we can prevent them? We went away and designed a study that different countries could do.'

Geopolitical events then intervened. ‘We had the break-up of the Soviet Union,’ she says. ‘We’d expected the Russians to put the study in one of their five-year plans, but suddenly they couldn’t get it funded. Other countries didn’t have a national health service, and would have found it much more difficult to do. It was down to us, which was fine by me. Because I was working at the University of Bristol and had access to the NHS, this area became the major centre for the work.’

The idea quickly captured the imagination of the local media. ‘Television and press were happy to cover the study and persuade people to take part,’ she says. ‘We started in 1990, enrolling any women who were pregnant and had an expected date of delivery between the start of April 1991 and the end of December 1992. To my delight, many women saw the point of the study and wanted to be involved: almost 72% of those we invited said yes.’

Funding was a constant problem. The study was unprecedented in its scale and scope, and Jean struggled to convince grant-awarding bodies of its viability. Fortunately, the University recognised it as a worthy investment, and allowed it to run up a debt under a temporary arrangement – although this meant relying on the goodwill of staff to keep work on track.

‘We had a lot of people working with us to collect data and interview participants,’ recalls Jean. ‘We were so short of money, they could only be paid one month at a time. Even though they didn’t have the next month’s contract, they kept on working. It was absolutely fantastic that our staff were so enthusiastic, and put up with this. It really was hand to mouth.’

Establishing a rapport with the study’s participants was even more important, and it’s a measure of the team’s success that around half of the original volunteers are still involved. Jean says: ‘It was very much a joint enterprise, and still is. We wanted our participants to know how important the study has been in preventing deaths and improving health, motivating them to feel they can make a difference.’

The study soon took on a personal dimension for Melanie Davis. ‘My daughter Melissa was diagnosed with cancer when she was 12,’ she says. ‘I felt it was more important than ever that I complete the questionnaires and attend the appointments. I wanted our answers to help researchers find out why young people get these diseases. You have to hope that this research will help improve the health of our children, grandchildren and great-grandchildren, further down the line.’

For Melissa, Children of the 90s has been a fact of life through childhood, adulthood and now parenthood. ‘It’s something I feel very proud to be a part of’, she says. ‘When I was younger, it was a much looked-forward-to day off school. I enjoyed attending the clinic – the staff are always so friendly, and rewarded us for our time. Now I’ve enrolled my own two children.

‘I’ve had various diagnoses in the past, including Hodgkin lymphoma twice, so I’m very happy to be a part of a study that can lead to breakthroughs in science that will benefit future generations.’

Steering policy, changing lives

The breakthroughs delivered by Children of the 90s have driven health policy across the world. Nic Timpson (PhD 2008, PGCert 2013), Professor of Genetic Epidemiology at Bristol Medical School has been the study’s Principal Investigator since 2017. He says: ‘The breadth of the study’s contributions is mind-blowing. I could list examples all day.'

It’s a difficult exercise to come up with a playlist of the study’s most influential findings. Both Jean and Nic include the discovery that placing babies on their back to sleep could vastly reduce the incidence of sudden infant death syndrome. This helped persuade authorities in the UK, the US and elsewhere to launch comprehensive public health campaigns.

Nic also points to research on the use of peanut oil in skin creams. Scientists linked this to an increased likelihood of children developing a peanut allergy, prompting manufacturers to reformulate their products or include warning labels. Another high-profile finding helped to dispel media scare stories about whether fish could safely be eaten during pregnancy.

As to more recent work, Nic brings up the discovery that one in five young people have signs of a fatty liver associated with being overweight or obese. It’s a condition that often goes unnoticed, but which can lead to serious illness and early death if untreated.

Previously, liver disease had been considered a problem mainly affecting the over-40s, with little information about how common it was in younger people. ‘If you’re doing an ultrasound on someone’s liver, it’s likely to be that of a later-aged adult who is very poorly, not an apparently healthy 30-year-old,’ says Nic. ‘There’s rarely a reason for scanning younger people, as we do as part of Children of the 90s, and as a result there was less of an idea of what was happening earlier on in someone’s life.’

Detecting this sort of health trend demands the in-depth data that only a large longitudinal study such as Children of the 90s can provide. Nic says: ‘One of the great things is the ability to have a layered portrait of somebody’s life. You understand what’s happening to someone, both medically and in other areas of their life, which is key to health.

‘You can deep-dive on what’s happening in their blood or their tissues, what changes over time, how their genes relate to it, how it relates to environment and socio-economic factors, and so much more. A really rich picture develops about somebody – not just at one age, but as they move through time. This long-term, detailed data, when analysed in a collection from many participants, presents an extraordinary research opportunity that just doesn’t exist in any other study.’

The genetics of weight gain

A familiar face from BBC science documentaries, Giles Yeo MBE is Professor of Molecular Neuroendocrinology at the University of Cambridge’s MRC Metabolic Diseases Unit. His work shows how an individual’s genetic make-up can be a major factor in childhood obesity. Working with the Children of the 90s datasets, Giles and his team looked at the prevalence of a mutation in the MC4R gene across the population. This can have a profound effect on weight gain, with those affected an average two-and-a-half stone heavier by the age of 18.

‘We needed to look at a birth cohort, and that was where Children of the 90s came in. It’s a unique study. It’s unusual in that we have longitudinal data collected from birth, which allows us to ask some important questions.’

Like many insights yielded by Children of the 90s, Giles’ discoveries challenge ingrained assumptions and provide evidence to rebalance public health policy. ‘The prevailing view is that obesity is a lifestyle choice,’ he says. ‘Governments push personal responsibility when it comes to managing it, but we can’t ignore the role that genes play. People who struggle with weight gain may be fighting their own biology. They’re not morally bereft, bad or slothful.’

Mobilising the data

In 2020, the COVID-19 pandemic suddenly placed Children of the 90s on high alert. Nic says: ‘We were in overdrive. We ran seven, maybe eight questionnaires and coordinated with studies across the UK. We ran face-to-face clinics and did antibody testing. We had evidence going out on the mental-health effects of lockdown, the economic ups and downs of being stuck at home, and the age gradient for COVID-19 related lockdown and infection effects.’

Team members took part in daily meetings with colleagues across the academic community, and made their expertise available to government committees. ‘We still have a lot of important work going on around long COVID, but I’ve never experienced anything like those months of the pandemic,’ says Nic. ‘I don’t think there will be another moment when we can say so clearly to the public, “Look – can you see how we can harness data to help?”’

With data science having advanced beyond recognition since Children of the 90s began, Nic and his team are acutely aware of their responsibilities as custodians of sensitive personal information. In her earliest projects, Jean remembers storing data by punching holes in index cards and sorting them by pushing a knitting needle through the pile. Today, the processing power of modern computers can crunch many hundreds of data points in a blink.

Nic says: ‘For those who own the data and share it with us, we want a situation akin to carrying an organ donation card. They should be able to think, “This is my contribution, I understand it, I want my data to help and it’s safe to take part.” We don’t want them to have any suspicions about how we use data, but to feel confident in how their contribution is making a big difference.’

Filling the generation gap

As its half-century anniversary draws closer, where next for Children of the 90s? While a new generation of participants brings the study full circle, the advancing age of the original child cohort offers the chance to put a neglected group under the microscope.

Nic says: ‘15 years ago, we were interested in adolescence and watching our children become adults. Now they’re in their mid-30s, and nobody really focuses on 30 to 40-year-olds. They’re deemed to be healthy people doing their thing.

‘But when you think about it, there’s a lot going on at this age. Grandparents may be getting older and facing health challenges, families may be changing, and there is the joy, stress and strain of daily life. Our job over the coming years is to make sure that we sensitively and precisely capture all that, and understand it better.’

While its impact is global, Children of the 90s is very much Bristol’s own. Its relationship with the city and region is a reciprocal one, with data helping local healthcare providers prioritise resources and improve care.

And although it’s difficult to gauge how much of the project’s success is down to local factors, many researchers have found residents unusually open and welcoming to their ideas. Nic points out that other large participant studies, such as UK Biobank, have had some of their best response rates from the public in Bristol.

It’s undoubtedly a source of pride for the University, city and region alike. Jean says: ‘I still get stopped in the street by people who say, “Oh, I know who you are. My daughter is part of the study,” or “My neighbour’s daughter is in the study.” It’s not just the participants – everyone knows someone who’s part of it. And that’s so important, because it’s this enthusiasm that has kept us going.’

Can you help?

If you were born between April 1991 and December 1992 in Bristol or the surrounding area, you can still sign up to be part of this life-changing study. Researchers are particularly keen to hear from participants now starting their own families. For more details, please email info@childrenofthe90s.ac.uk.

Listen to Professor Jean Golding OBE (DSc 1994, Hon LLD 2013), Founder of Children of the 90s, on Desert Island Discs.