This article was first published in the June 2016 issue of WIRED magazine. Be the first to read WIRED's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online.
George Davey Smith wants to get his hands on the blood of millennials. To be more specific, he needs to convince several thousand of them, aged around 24, to be weighed, prodded and quizzed, donate blood and urine as well as undergo scans of their livers, hearts, necks and entire bodies.
The reason: Davey Smith, an epidemiologist, is leading a study that has been tracking around 14,000 children since birth to understand the many influences on their health and development. And those children are now young adults.
Davey Smith, 57, and his colleagues have already amassed a biological treasure trove from this group, the Avon Longitudinal study of Parents and Children (ALSPAC). Below his Bristol office, in locked basement storerooms and freezers, lies a macabre bank of samples collected since their births between 1991 and 1992. There are thousands of tufts of hair, nail clippings, milk teeth, umbilical cords, tubes of blood plasma and urine. (There are also around 9,000 placentas floating in plastic buckets in a secure storage barn a few kilometres away.)
Add to that the reams of data that the scientists have vacuumed up - the participants and their parents have filled in more than 100 questionnaires with enquiries ranging from nappy rash to self-harm to sex - and this makes these millennials some of the most studied people in the world.
Their data has been used in more than 1,200 academic papers worldwide, including ones showing the benefits of eating fish during pregnancy, that peanut oil in baby lotions is linked to later peanut allergy, and that 15 minutes of exercise a day halves the risk of childhood obesity. DNA analyses have helped identify genes involved in obesity, eczema, foetal growth and much more.
This may sound a lot, but the Bristol study is part of a bigger and more unusual enterprise, a remarkable series of birth cohort studies that have tracked successive generations born in Britain. The first of these started when scientists recorded the birth of almost every child born in one week in 1946 (1). Scientists are also following thousands of British children born in 1958, 1970, and the turn of the millennium. There are some 70,000 people in these five studies and no other country has a project quite like it.
In the 40s, the first cohort revealed shocking differences in prenatal care and infant mortality between the working classes and the more well-to-do, which helped shape the fledgling NHS (2). In later decades, they revealed the link between smoking in pregnancy and infant mortality, helped show the links between foetal development and adult conditions such as heart disease, and revealed how obesity hit Britain in the 80s (more people in the first three cohorts put on weight then).
But in some senses, the studies are only just coming into their own. Davey Smith and his team have made sure that the 90s cohort stays at the forefront in the age of omics and big data. Two thousand cohort members have had their full genome sequenced, and the scientists are now embracing studies of the epigenome, metabolome, transcriptome, microbiome and more. Unlike other such studies, this detailed molecular data can be connected to the wealth of information collected across the participants' lives to try to better understand health and disease.
"The sheer amount of this data sets it apart," says Lynn Molloy, executive director of ALSPAC. The power comes in having some of these measurements through time, she explains.
The study has built up maps of epigenetic marks - the chemical marks on DNA that alter the way in which genes behave - across the genomes of thousands of mothers and children. Last year, researchers put that data to use, showing that children of mothers who smoked during pregnancy had a particular pattern of epigenetic marks and that, as the children grew up, some of those marks vanished but some stayed.
They hope is to use these types of study to pinpoint the biological mechanisms that connect the two - precisely how the toxins in smoke send genes and cells awry. Researchers around the world are keen to use the data: "We have a clutch of proposals every week," says Nicholas Timpson, a genetic epidemiologist who leads many of the omic studies for ALSPAC.
Data continues to stack up. Around 1,000 cohort members have already attended the latest clinic, Focus @ 24+, which will collect measurements when these young adults are at their physical prime. One aim is to find the early signs of cardiovascular problems (3). "At this age, you'd expect them to be healthy − and there is not much research on cardiovascular health in this age group," Molloy says. "But we are picking up problems."
Another project will also start this year involving wiring up the bodies and homes of 30 study members with sensors to measure how active they are, and in-house sensors and cameras to monitor eating, sleeping and TV watching. Part of the motivation, says Molloy, is to see whether it's possible to collect data remotely, without members having to give up their time.
Meanwhile, the scientists are doing their best to attract volunteers into the clinic. Timpson says he is always surprised by the commitment of the people involved. "There's a lot of data just because people have given their time, samples and permission. We are stunned at how interested they are in what we're doing."
Helen Pearson is the author of The Life Project (Allen Lane)
1. The 1946 cohort has been followed ever since. In March 2016, the group celebrated turning 70 and being part of the longest continuous, major birth cohort study in the world. 2. The data has repeatedly shown that children born into disadvantage often lead more difficult lives than the wealthy. However, interested, involved parents can go some way towards ameliorating these disadvantages. 3. The tests of heart and blood vessels include 12 measurements of blood pressure, taken when sitting, standing and exercising. The participants also wear an activity monitor for four days.
This article was originally published by WIRED UK
