1 MELLOW MUSIC What if we took a baby and watched everything that happened to it from birth to grave? If we examined every aspect of its life, looked at everything that happened to them and everything that made them who they are? Their physical development, their personality ` their emotional ups and downs, criminal convictions, relationships, illnesses, highlights and heartbreaks. Then imagine if we did that for and entire city. Perhaps we could uncover what it is that really makes us who we are. That experiment has already begun. In 1972, the University of Otago Medical School embarked on the ultimate nature vs nurture test. They decided to take every child born in the city that year and follow them for life. For 40 years scientists have probed every nook and cranny of their existence. READS: A. Their medical history, their temperament, their genes. Their private lives, successes, failures ` the lot. How many times have you sold hard drugs, like heroin, cocaine or LSD? The experiment is called the Dunedin Study and its subjects are now the thousand most-studied people in the world. And they've become the richest source of information on what really makes us who we are. Copyright Able 2016 Over the past two centuries, technology has made life easier. Our world is cleaner, and medical advances mean we are healthier. But while our lives may be more convenient than in the past, we also face new and often unforeseen perils. The Dunedin Study has discovered that living in a modern world has some surprising consequences. SWELLING MUSIC LYRICAL MUSIC The first bad asthma attack that Conrad had, um, he was about 18 months old. It started during the night. And we had to give him the nebuliser ` a machine, it makes loud noise, and there's smoke and steam coming up, and he'd be crying the whole time. So that added to the stress of the situation, was trying to make him have a mask over his face to be able to breathe. Having asthma feels like drowning. When I'm having an asthma attack, it's really scary. You feel really scared that you might, like, die on the spot. Conrad is 9 years old and suffers from asthma. He's not alone. 300 million other people around the world suffer from asthma, and the number is growing, especially in developed countries. But what exactly is asthma? Asthma's where the airways, the breathing tubes in the lungs, get narrowed, and often that's in response to an allergic reaction inside the airways. So the airways get narrower than they should be, and it becomes difficult to breathe. So people recognise that; they feel tight in the chest and sometimes short of breath. They have noisy breathing, and often their parents or other people hear whistling in the chest as they breathe in the night. Asthma and allergic disease rates have risen dramatically in the last few decades. In the 1950s, asthma affected less than 1% of the general population. The current rate is at least 10 times that in developed countries. And it's not just a matter of being short of breath. Asthma kills 3500 people each year in the United States alone. The 1037 babies in the Dunedin Study followed the same pattern. Those that we would recognise as having persistent, allergic-type asthma is around 15% to 18%. The percentage has risen in most countries in the last 20 years. Now, it's probably about 50% higher than it was a decade or so. But why? The most obvious culprit was increased air pollution from traffic and urban smog. But the Dunedin results support a surprising new theory, one that becomes more obvious when immigrants moved to a new country. Professor Malcolm Sears discovered Chinese immigrants in North America had higher rates of asthma than their relatives who'd stayed in China. Interesting thing is that the rate of asthma goes up. The longer you've been exposed to whatever the new environment is there, the higher that risk. The same pattern is seen across the Western world. When immigrant families move to a developed nation, asthma and allergies increase. In fact, allergies can travel in as little as 10 years after moving to a developed country. There's something that's generalisable across the world, that more developed populations have higher prevalences of asthma. Conversely, children from undeveloped countries, where there might be more exposure to things in the environment ` perhaps more germs or microbes ` they seem to be protected to a large extent against the development of allergies. So with an affluent society, we've ended up with an increased rate of allergy. So why should moving to a city like San Francisco or Dunedin make people more prone to asthma and allergies than living in a country like China? The Dunedin results point to an explanation called the hygiene hypothesis. It was originally proposed over 20 years ago now that children who came from very large families were less likely to have allergies than children who came from small families. The idea was that children with lots of brothers and sisters got exposed to lots of infections that their siblings brought back home. It may seem like an odd notion, but this is exactly what happened in the Dunedin Study results. It seemed quite a ridiculous idea at the time, but the study members who've got more brothers and sisters are indeed less likely to have allergies than those who are only children or have only got one sibling. Other studies have found it's not just big families that provide protection from allergies. Children brought up on farms are less likely to develop asthma, and the Dunedin Study found this also applies to urban families with pets. There are a number of aspects which sort of hint towards the hygiene hypothesis being true. For example, we've discovered that children who grew up with cats and dogs at home were less likely to develop allergies than those that grew up with no pets. Children who had, in their early childhood, exposure to cats and dogs ` where conventional wisdom would say they're more likely to become allergic to cats and dogs if they're exposed to them ` it's actually the reverse. One theory is having cats and dogs increases the amount of dirt a child is exposed to, and that protects them. If children have early childhood exposure, particularly to dogs, early childhood reduces the risk of allergies. The findings relate to a substance called endotoxin, which is one of the bacterial by-products that is in the dust, and animals stir up the dust, and it was identified initially that farming children had much lower prevalences of allergy and asthma, and this has now been translated into looking at domestic animal exposure as well. The hygiene hypothesis says it's not really dirt but microbes that matter. And by zealously cleaning and sanitising our modern world, we're reducing our exposure to microorganisms and bacteria. As we make our environment cleaner and cleaner, we're inadvertently opening ourselves up to increased rates of asthma and allergies. We have an immune system that was designed to fight off parasites and infections and so forth, and as we become cleaner and cleaner and have fewer parasites or infections to deal with, the system has reoriented itself a bit and begun to deal with things that form allergies. The theory says we need to expose ourselves to a large range of microbes to develop a healthy immune system, and the Dunedin Longitudinal Study has some paradoxical advice to minimise your chance of developing asthma and allergies. One ` choose your parents carefully, because there is clearly a genetic component, and if a mother or father has asthma or allergy, there's a much higher risk that the child will. But this whole question of early childhood exposure is raising a lot of interesting things, and I sometimes rather facetiously say, 'Well, the best advice is when you're on your way home 'from the maternity hospital, stop at the pet shop and buy a dog, maybe two dogs. 'Really, something that will stir up the dirt, and let your child play in the dirt. It's good for them.' URGENT MUSIC A fundamental part of being human is our desire to interact and connect with others. More than half the world's population now live in urban areas, meaning we encounter and engage with hundreds, if not thousands of other people on a daily basis. But even in the middle of a busy city, there are some who aren't mixing with everyone else. I remember as a teenager I felt constrained, and I was looking at myself in the mirror and suddenly the thought came, 'Nun. Convent.' And I wanted to be quite radical, and the Carmelites seemed to be the most radical of the lot. The Carmelite nuns choose a life away from the rest of society. We have three vows ` poverty, chastity and obedience ` but it's the Carmelite rule that obliges us to silence. And in practice that means from about quarter past 8 until almost mass time the following day, say about 7 o'clock, we keep the Great Silence. With the exception of a few sisters, the women do not mix with the outside world. They spend their day in prayer and making altar breads for parishes around the country. During the rest of the day we are allowed to speak if it's something really necessary, but just ordinary conversation we keep for recreation time. But we do speak and speak a lot at recreation time. Social isolation is a lifestyle choice for the Carmelites, and one the nuns find rewarding. Silence is not an absence; it's not a negative; it's a positive. If it's the right kind of silence, I might add. Everybody knows in their ordinary social life that you can get all sorts of silence. There's a friendly silence, a peaceful silence, but there can also be a quite bad sort of silence, and that, of course, is to be avoided by all means. As Sister Mariam observes, not all silences are good silences, and modern life often allows us to be separated from the rest of society even in a crowd. Dunedin researchers were interested in the effects of being socially isolated when we didn't necessarily choose it, and in particular, the experience of growing up feeling isolated. The study went back through its records and identified study members who'd grown up as lonely children, kids whose parents and teachers described as being solitary and not fitting in with the crowd. It's the child who doesn't have anyone to play with. It's the child who doesn't get invited to participate in activities and in sport. You know, the children who are terribly terribly lonely, that they don't know how to enter the social world, be it because they're withdrawn and inhibited or be it because they often lack the very social skills that are necessary to join other children. Dunedin researchers found lonely children often grew up to be socially disadvantaged adults. Many of them are much more likely to grow up to be anxious adults. They are also more likely to develop depression, and over the course of time they've also failed to accumulate the friends and the networks that would help many others cope with difficult times. So when things go bad, when you lose your job, when your relationships break up, they have a harder time securing social support that would enable them to weather the challenges that, you know, life throws at you. But the real surprise in the Dunedin results was the problems weren't just psychological. The negative effects were also physical. By the time they were 26, the adults in the study who'd been social outcasts as children were more overweight, had higher blood pressure and worse cholesterol. They were heart disease and stroke risks. I don't think anyone is surprised at their mental health consequences, but the fact that there are physical health consequences? I don't think we would've expected that. We see elevated stress biomarkers, elevated inflammation, so they're basically much poorer health than are their more outgoing peers. Other studies back up the Dunedin results. The health risk caused by loneliness has been estimated to be the equivalent of smoking 15 cigarettes a day and being an alcoholic, and the longer someone spends out of favour as a child, the worse their health will be as an adult. You can say all the adversities have this snowball effect. But the puzzle is that for many, those adversities have lasted often, you know, in the absence of later adversities. The same mechanism seems to operate in other primates. We see parallel developmental changes. The gregarious monkeys will go out and look for friends, and the shy monkeys will go in the corner and wait and watch, and if they're lucky, somebody will come over and interact with them. But they're very reluctant to initiate those kinds of interactions. And they'll show a particular pattern of not only a behavioural response but a rise in cortisol levels, so they show the same kind of biological response to comparable social situations as you see in young children. Like their human counterparts, socially isolated monkeys have supressed immune systems, increased inflammation and other health issues. It seems that the need to belong is universal, and if thwarted, can result in a series of biological processes and actually get under the skin to cause physical ill health. The Dunedin Study also discovered the health problems were not the result of lifestyle choices isolated kids made. Loneliness is just bad for our bodies by itself. These childhood experiences really do matter. They really do have these enduring signatures on the body. And that's a puzzle for all of us to try to figure out how it is that those early experiences become imbedded and have such long-lasting effects. Fortunately, it's not necessary to understand the exact mechanism to help. Here you have an identifiable risk factor that you can do something about. Think about it. I mean, isolated kids are easy to spot. And if you know that that's a signal for later risk down the track, you can actually do something there and then. 1 UPBEAT MUSIC Did you realise that the average NZ home produces around 8 litres of moisture a day? Over a year, it's the equivalent of two of these. Moisture is created by day-to-day living, like indoor clothes drying, cooking and showering. Rising damp from beneath your house can add to the problem. Damp homes are harder to heat, and they're bad for our health. So reduce moisture by opening windows and doors regularly to let fresh air circulate, use externally vented fans in kitchens, bathrooms and laundries, dry your clothes outside when you can, and make sure you sort out insulation and heating too. Here's a tip ` always address the sources of moisture in your home before considering installing a ventilation or dehumidifying system. Check out energywise.govt.nz for advice on how to solve dampness in your home. Reducing moisture improves your warmth, comfort and health. I'll see you next time. 1 SUBDUED MUSIC The Dunedin Study has been scrutinising the lives of 1000 people for over 40 years now and has established itself as a mirror of life in any modern society. The research represents the combined data of 40,000 years of human life and experience and is revolutionising our understanding of what makes us who we are. The study has uncovered unexpected connections between our genes and the environment as well as the long-term effects of our personality and behaviour. And the study continues to expand its range of tests, looking for information hidden in less obvious places ` locations perhaps not normally seen by the human eye. Welcome. We start with blood pressure measurement. You've done that every time you've come back to see us. The next test is new ` the retinal eye photograph. The operator zooms in until the pupil of your eye fills her viewfinder, and then they'll take a photo. And just look straight ahead. We're just focusing in on your pupil. When the Dunedin Study members were 38, we gave them a brand-new type of a test, which is to take a digital photograph of the back of the eyeball, the retina, and there in those photographs you can see the very tiny micro blood vessels. Nice and still. Researchers were hoping the inside of the eye would provide an insight into the function and health of something a lot harder to get at ` the inside of the brain. Now, it's not possible for scientists to see what the blood vessels are like inside the brain because a person has to die first before you can get brain tissue, so in a living individual, we can't look inside their brain to look at how oxygen is brought to the brain by blood vessels, or how toxins are taken away. But you can do that in the eye. And when there are abnormalities in those blood vessels, what's really interesting about it is that the blood vessels in the eye are just like those inside the brain. Dunedin researchers discovered tiny blood vessels which carry blood away from brain cells called venules were notably larger in some people. Not surprisingly, many of these people had hypertension or high blood pressure. But there was a group with normal blood pressure who also had larger venules. And those people had schizophrenia. People who had schizophrenia had wider venules, and the only other people in the study who had such wide venules were those with very high blood pressure, with hypertension. What that probably means is that the venules are more, perhaps, elastic, plastic, than the arteries, and they are showing the effects of poor vascular circulation to the brain earlier in life. Schizophrenia affects one in 100 people. But why would a mental illness have anything to do with vessels that transport blood around the body? And why would schizophrenic brains have smaller blood vessels than others? With schizophrenia, things are wrong all over the brain. When they do the kinds of brain imaging that look at functional connections between different parts of the brain, they see that all those connections are working in an abnormal way. So whatever is wrong with schizophrenia, it's not in one tiny box, one tiny part of the brain. It's something that is diffuse all over the brain, and a key aspect of what's diffuse is blood flow. Scientists don't know what causes schizophrenia, but the new Dunedin results lend support for one particular explanation. The vascular theory is just a simple theory that either oxygen flow toward the brain is abnormal or the flow of toxins away from the brain might be impeded. The finding that we have showing that it's the venules that are abnormal in people with schizophrenia suggests that it might be the latter. So we were very interested in blood flow as the best measure of the vascular theory of schizophrenia because it can account for there being abnormalities all over the brain instead of just in one spot. So what do the results imply about the cause of schizophrenia? We're not exactly certain what's the chicken and what's the egg, but it looks like whatever the process is has been going on at least since they were age 11. My guess, if I had to put money on it, is that it's a cause. There is a long history of theories of microvascular problems in schizophrenia, so that these theories suggest that vascular problems, or problems with the delivery of the oxygen and the nutrients that come in the blood, problems with delivery of this oxygen nutrients to the brain, are not so great for the brain, and that might cause psychosis and that might also cause neuropsychological impairment that we see in schizophrenia. So do the Dunedin results suggest a new way of screening for schizophrenia, perhaps even before behavioural symptoms arrive? You really can start with quite young children and see whether vascular abnormalities come first before any kinds of neurological or mental health problems. My only regret is that we didn't have this technology to look at the eyes of the Dunedin Study members when they were growing up. So we started a bit late when they're 38-year-olds, but it's because the retinol imaging of the eye only became available. Schizophrenia has significant social and economic effects, as well as causing incalculable personal and family distress. Most countries spend between 1.5% and 3% of their total healthcare budget dealing with this condition. In the United States alone, schizophrenia is estimated to cost in excess of $50 billion a year. So do the Dunedin findings suggest a new way of treating the illness? I think if this vascular theory of schizophrenia, if it turns out to be really meaty, if it's supported by a lot of different research, it would take people in the direction of thinking what can we do to improve and alter blood flow and perhaps from early life as a preventive mechanism. So it may lead to treatments. It may lead to preventions. There are ways to affect the vascular system, but they just haven't been applied yet to this particular illness. There is one team in Israel who has used the kind of machine that people get who have sleep disorders to feed oxygen to them through a mask while they're asleep, and they claim to have reduced the symptoms of schizophrenia by having people with schizophrenia sleep with one of these oxygen masks. Whether that will be replicated, I don't know, but it's very provocative. If we can treat them with oxygen supplementation or treat this vascular problem, then maybe we could help reverse some of the symptoms. I think that the biggest implication again ` again this isn't something that we've shown ` but in the future, we could maybe even show that this process starts early in life, and we can look at kids and look in their eyes and say, 'You know what? These kids have wider venules and they are at risk for developing schizophrenia. 'Perhaps there's something that we can do to interrupt that process.' There were other surprises from inside the eye. People who had wider venules at age 38 also had a lower IQ in childhood, as well as problems with verbal comprehension, perceptual reasoning and working memory. The usefulness of this retinol measure might not be limited only to people who have brain diseases. It may be that there's a distribution, a dimension right throughout the population of how well one's brain can function, and that that's dependent upon the vascular blood flow to the brain. That would make good biological sense. There's no reason why it should be limited to only people who have neurological diseases. Just moving over to your left eye now. The Dunedin findings may point the way to a new diagnostic tool for a range of neurological disorders and suggest innovative treatments for currently untreatable conditions. It's new technology. I think it's unproven at the moment exactly how far it can go as being a useful diagnostic tool for doctors to use, but there's great excitement about it. INTRIGUING MUSIC One of the unfortunate features of the modern world is a growing disparity between rich and poor. Even the most affluent cities have deprived neighbourhoods. The Dunedin Study has discovered something surprising about the difference between growing up rich and poor ` results that go far beyond social and economic consequence. Bayview-Hunters Point is one of the poorest neighbourhoods in the United States. Household incomes are half those in neighbouring suburbs. It has far higher rates of unemployment, poverty, disease and crime than other parts of San Francisco. In a city with so many resources, where it's a very wealthy city, Bayview-Hunters Point is almost like a little slice of the third world in the middle of this amazing world-class city. Dr Nadine Burke Harris runs a community clinic in Bayview-Hunters Point. Burke Harris was concerned her patients were doing particularly badly compared to those just a few miles away in more affluent suburbs. When you compare health outcomes in the same city, the rates of hospitalisation for diabetes are 12 times higher. The hospitalisation for heart disease ` five or six times higher. Things like infant mortality, they're just off the charts in this neighbourhood as compared to other places in the city. 10,000 miles away on the other side of the Pacific Ocean, NZ paediatrician Dr Adrian Trenholme sees exactly the same issues. The overwhelming thing is the kids get infectious diseases that they probably shouldn't be getting. If you go through the body, I see the dental issues, the respiratory issues, the heart issues, rheumatic fever, kidney issues, which are due to infections, skin infections, bone infections, joint infections, meningitis. They're three to five times more likely to be admitted to hospital with lower respiratory infection compared with my kids. Like Bayview in San Francisco, South Auckland is a particularly poor area. Incomes are less than half those in more affluent parts of Auckland, unemployment is higher and life expectancy is seven years less than in wealthy neighbourhoods. Both Bayview and South Auckland have appalling health statistics compared to surrounding suburbs. I look at my kids and they're healthy, and they haven't faced the health issues. 10 K's away, there's kids facing repeated health issues, and they're gonna have chronic disease and end up disadvantaged in life. And why? If I'm looking at one of my newborns, and I think to myself, 'If this baby, if her parents lived on the other side of town, her life expectancy would be 11 years longer. 'Why is that?' The idea that poor people have bad health is not new, but the Dunedin Study wanted to go one step further. What happens to people who grow up poor and get rich? We asked whether it was possible for those people who had crawled up out of poverty by dint of their own hard work and perhaps gotten a lot of education and gotten a very good-paying job, if they had better health than would be expected. The results of the Dunedin analysis were completely unexpected. Researchers discovered becoming wealthy doesn't fix your health problems. The physical effects of growing up poor remain. Getting out of poverty by the time you're an adult can't undo the damage that's already occurred. In other words, what happens during those childhood years has a long-lasting, far-reaching impact upon how your health is gonna be as an adult. Up until that point, scientists had assumed that improved and more affluent living conditions would reverse the effects of growing up poor. One would have expected them to have dissipated with time. One would've expected for other events to have undone some of the adversities the children had experienced. And yet they linger. The Dunedin findings demonstrate poverty is not just an economic or a social issue. It is also a physiological condition that permanently weakens people, making them susceptible to repeated bouts of illness and poor health. This was an exciting finding that I don't think anyone would have anticipated. That's such a radical finding. Nobody actually expected that. And I think it's been very important for all of medicine to recognise. And the Dunedin researchers thought they knew why. The stress of growing up poor leads to chronic inflammation. Inflammation indicators in blood are most abnormal among the study members who suffered abuse and neglect when they were very young children. This is important because these inflammation indicators are some of our best predictors of who's going to develop heart disease in the next 15 or 20 years, so it's a window inside how chronic stress during childhood has altered the immune system in a way that is setting these young people up to be vulnerable. The publication of the Dunedin results changed the way Burke Harris looked at her patients' medical problems. What this study does is demonstrate that children who are exposed to maltreatment or adversity had a higher sensitivity CRP in adulthood than children who are not maltreated. That tells us about the biology, the physiology, the inflammation that happens in the body as a result of exposure to childhood trauma. And for me that was very powerful. As the twig is bent, that's the way the tree grows. The stress that you experience in a conflicted family when being exposed to child maltreatment in particular, that does things to the physiological stress system. That leaves you in later life to have more inflammation, and that is not good in terms of health and well-being, in terms of the cost of healthcare and lots of other things. Through no fault of their own, children growing up in poor and particularly in violent homes, suffer stress, which causes physiological wear and tear during their formative years. Bad stuff happens to you when you're a kid, even if you're an angel, when you get to adulthood, you still have increased chronic inflammation. So that makes it so that it's not just an issue of people who make bad choices. It's really an issue for all of us, that exposure to adversity increases your risk of inflammation and diseases of chronic inflammation. The lesson from the study's findings is that poverty is not just an economic problem. It causes a physiological illness that lasts. So all of a sudden there's almost a brand-new reason, if you would, to imbue the early years with meaning, to structure social policies to foster well-being beyond just it's a bloody nice thing to do and we should treat children well. And that is because it's gonna save us healthcare dollars down the road. I think in the end it will lead to a very promising approach ` a much deeper notion of exactly what poverty is, what it does and why alleviating poverty in the young, among the families that are producing the young children, why creating the right conditions for development can be such an important activity for governments and society at large to consider. To improve the health of a community takes more than just good medical facilities. The Dunedin findings show you have to start young and prevent the illnesses of poverty taking hold in the first place. UPBEAT MUSIC A tent can keep the rain off, but it can still get cold inside. A sleeping bag keeps you warm and comfortable by trapping heat in. Insulation in your home works the same way and makes a real difference. But don't just take my word for it. The house was, um, quite cold the first winter we were there. You'd have cold wind coming up between the floorboards. People wouldn't want to come and visit. Cam had asthma, and after the insulation was put in, dramatic improvement. So instead of lying in bed listening to him cough all night, we had good night's sleep ` both him and us. Anything less may increase the risk of respiratory disease. Hugely better family environment. It's one that we can enjoy rather than endure. Effective insulation and heating can mean fewer days with colds and sickness, which is better for all of us. 1 JAUNTY MUSIC The Dunedin Longitudinal Study has been going for over 40 years now. The study has grown in significance and impact. Researchers all over the world analyse its growing mountain of data. Founder of the study, Dr Phil Silva, could scarcely have imagined the influence and importance the study would achieve when he lodged it in 1972. Very proud of the legacy. I think that the publications and the output and the influences on policy and the fact that we've got the most documented sample of human beings ` large sample of human beings ` on the planet, that gives me a real sense of pride. The study has published on average a new scientific paper every two weeks for four decades, and those papers are highly significant. If I had a list of the publications these world-class scientists and scholars have generated, I could probably go on for hours. It's probably the world's most successful longitudinal study of a general community sample ever. It's an amazingly successful project. No question about it. If you calculate the impact factor of the Dunedin Study, it's probably the highest of any study, um, of the behavioural sciences, and it's creeping up there in the medical sciences as well. The study has made discoveries in virtually every area of human health and behaviour, including gene-by-environment interactions that cause violence; depression and schizophrenia; measurements in childhood that predict health and wealth in adult life; how to spot future criminals in kindergarten; and why teenagers run off the rails. The Dunedin Study is known in our field, in many fields, as just a hallmark and landmark study. I mean, just a brilliantly conceived study, and whoever came up with the idea should be really thanked. I mean, this is Nobel Prize-winning stuff. I will inspire you as you do me... The study has followed its subjects through all of life's milestones, from birth to middle age and all stages between. ...through good and bad days, and the highs and lows of life. The subjects are still anonymous, but they are an accurate representation of us all. Here we go. Do you want one, Nathan? You right? When I became involved in the study, I focused a lot on puberty, not necessarily because puberty was the topic that interested me the most, but because that was the salient event in the lives of the study members. By the age of 40, 60% of subjects were married. A few have even married each other. Three quarters are parents, and between them, they have almost 1700 children. Now that they're reaching middle age, I've become very interested in cardiovascular health. I don't think that 25 years ago I knew that that's the direction that my work would be taking, but it is what's becoming important in the lives of the study members. Only 35% of study members still live in Dunedin, and a quarter live overseas. Despite this, 97% of the original group are still part of the study. There really is a sense among the study members, among their families, that this has been a very special study, and it has represented the community. There's almost, if you will, a civic pride that I think has contributed to their attention. I think they've come to think of themselves as almost like an Olympic athletic team because the health science has become one of NZ's greatest exports to the world and they are the team who's carrying that. As study members have aged, researchers continue to accumulate a huge range of data about their lives and even tested the ageing process itself. Researchers measured a series of biomarkers which indicate true biological age as opposed to the subject's chronological age. The results shocked the scientists. Some study members were ageing three times faster than their friends, though a lucky few seemed to be defying the ageing process. Dunedin Study members, on most of the measures that we've taken, range in their physical age ` when they're all exactly chronologically 38 ` they range in their physical age from 25 to 65. For example, a 38-year-old who's lived a tough life, smoked a lot, drunk a lot, eaten poorly, may have the heart of, or the lungs of, maybe a 58-year-old. And to add insult to injury, the biologically older group looked older, too. Each of them very kindly agreed to have a facial photograph made. And we had undergraduate students look at each of the photographs, and they tried to guess how old the Dunedin Study member was. Based on photos alone, the students ranked people's ages in exactly the same order as the physiological tests. The biologically older study members had the biggest decline in cognitive and IQ scores. Their brains were also ageing faster. This research has important implications for health services around the world. There'll be 400 million people aged over 80 by the year 2050. This will bring with it an enormous burden of disease and disability unless we find a way to extend healthy lifespans. So, what is the future of the study for the next 40 years? Thinking ahead to the future of the study, we plan to see them on into the future as long as they will continue to take part. It'll carry on until the last study member is still breathing, I hope, and that will be the end of data collection; it won't be the end of writing papers. The study continues to expand its areas of interest and range of tests. I think that there's more to be learned, more to be gained, and the study's getting better as we go. It should only improve from here on out. We should learn more about the process of ageing, the process of coping with old age, the process of maintaining our health into our later years, so if the Dunedin Study members will put up with us, we will keep watching them as they grow to be very old indeed. But of course, the real future of the study is not what it says about the 1000 study members but what it will reveal about the rest of us. It's an amazing record of the journey from birth, through childhood to adulthood and beyond, and it will continue to be an incredible source of information about what makes us all who we are.