Bibliographical Notes and Sources

Much of this book is based on extensive interviews conducted over five years with scientists, cohort members and others connected with the cohorts.

The studies have generated a vast range of publications across many disciplines and I have also drawn from this body of work. The sources I consulted are too numerous to list comprehensively. The following notes therefore feature a selection that were particularly valuable, important or enlightening, as well as providing references for some of the key studies mentioned. They are intended both as an acknowledgement and as a pointer to further reading.

General

A Companion to Life Course Studies, edited by Michael Wadsworth and John Bynner (2011), provides a detailed picture of the social, scientific and historical context in which the five British birth cohort studies have taken place. Michael Wadsworth has meticulously documented the history of the 1946 cohort, which he relayed to me in extensive interviews, and which he has also written up in two papers: ‘The origins and innovatory nature of the 1946 British national birth cohort study’, Longitudinal and Life Course Studies 1 (2), 121–36 (2010), and ‘Focussing and funding a longitudinal study of health over 20 years: the MRC National Survey of Health and Development from 16 to 36 years’, Longitudinal and Life Course Studies 5 (1), 79–92 (2014). I also drew on documents from the archives of the Medical Research Council held in the National Archives in Kew, Richmond, provided to me by Michael Wadsworth along with the handwritten notes he had made.

The history of social sciences and the Economic and Social Research Council (ESRC) is summarized in two invaluable documents: SSRC and ESRC: The First Forty Years (2005) and The Social Sciences Arrive (2000) by Alexandra Nicol. On the history of epidemiology, Kenneth Rothman’s second edition of Epidemiology: An Introduction (2012) and Rodolfo Saracci’s Epidemiology: A Very Short Introduction (2010) both provide for the reader what their titles promise.

A fascinating overview of the history and major findings of the 1958 cohort study is given in a report published to mark the cohort’s fiftieth birthday, Now we are 50 (2008), edited by Jane Elliott and Romesh Vaitilingam. This is also a good jumping-off point to further literature on the subject.

New research from around the world using cohort and other longitudinal studies is regularly published in Longitudinal and Life Course Studies and presented at the annual conference of the Society for Longitudinal and Life Course Studies.

The website for each cohort study provides an overview of the studies, a more comprehensive bibliography and, in some cases, details of questionnaires and other data collected:

1946 cohort: http://www.nshd.mrc.ac.uk/nshd/

1958, 1970 and millennium cohorts: http://www.cls.ioe.ac.uk

1991 cohort (ALSPAC): http://www.bristol.ac.uk/alspac/

Introduction

Escape from Disadvantage (1990) describes Doria Pilling’s journey to trace the 1958-born children who were born in difficult circumstances but went on to find relative success. The feature story that I wrote about the 1946 cohort is ‘Study of a lifetime’, Nature 471, 20–24 (2011); a few excerpts of which appear in this book.

PART ONE: Coming into the World

1. The Douglas Babies

The health visitor’s call on Gertrude Palmer was reconstructed based on interviews with her daughter Patricia and a visit to her childhood Cheltenham house as well as the questionnaire used in the 1946 maternity survey. The early history and results of the 1946 maternity survey are told in Maternity in Great Britain (1948), largely written by James Douglas but credited to the Joint Committee of the Royal College of Obstetricians and Gynaecologists and the Population Investigation Committee. The follow-up book, Children Under Five (1958), by James Douglas and J. M. Blomfield, fills out the early childhood years of the cohort.

Michael Wadsworth’s book The Imprint of Time (1991) was also essential in understanding the story of the 1946 cohort from birth to adulthood. The Population Investigation Committee: A Concise History to Mark its Fiftieth Anniversary, by C. M. Langford (1988), explains the concerns about Britain’s population decline, the formation of the Population Investigation Committee and the rationale for the 1946 maternity survey.

For James Douglas’s history with Solly Zuckerman, I drew on papers in the Zuckerman Archive at the University of East Anglia, which offer an astonishing and grisly insight into the classified work of scientists in the Casualty Survey as they documented the impacts of bomb blasts during the war. The Penguin paperback Science in War was published anonymously in 1940, but was authored by the Tots and Quots, a London dining club of young scientists formed by Zuckerman. The origins of social medicine are covered in John Pemberton’s paper ‘Origins and early history of the Society for Social Medicine in the UK and Ireland’, Journal of Epidemiology and Community Health 56, 342–6 (2002).

For the biographical details of James Douglas, I drew on interviews with Douglas’s family members and colleagues, and was fortunate to be able to consult a collection of letters, newspaper articles and other private papers provided to me by his widow, Rachel Douglas, who compiled it at his death in 1991.

The history of the cohort study methodology is drawn from sources including R. Doll, ‘Cohort studies: history of the method. I. Prospective cohort studies’, Sozial- und Präventivmedizin 46, 75–86 (2001). William Farr’s ‘Report upon the Mortality of Lunatics’ was published in the Journal of the Statistical Society of London 4 (1), 17–33 (1841). For additional reading, The Emperor of all Maladies (2011), by Siddhartha Mukherjee, and Tom’s River (2013), by Dan Fagin, are both Pulitzer prize-winning books which open a window on the history of epidemiology.

For the origins and history of the 1958 and 1970 cohorts, I drew on the archives of the National Birthday Trust Fund, housed in the Wellcome Library in London. The transcripts of the press conference at which the results of the 1958 cohort survey were first presented are a few sheaves of paper within an overwhelming stack of folders in these archives that document the sometimes farcical-sounding organization of the studies. The history of the National Birthday Trust Fund itself, the maternity surveys of 1946, 1958 and 1970, as well as the changing attitudes towards pregnancy and birth in Britain, are all meticulously documented in Women and Childbirth in the Twentieth Century (1997), by A. Susan Williams, a book which proved a precious resource.

For the biographical details of Neville Butler, I drew on interviews with Butler’s colleagues, friends and two daughters. The Centre for Longitudinal Studies also gave me a copy of a DVD featuring Butler and his work on the cohorts: Generations: The Life and Works of Neville Butler (2006).

Many details of the history and results of the 1958 Perinatal Mortality Survey are covered in the two major publications from its early years: Perinatal Mortality: The First Report of the 1958 British Perinatal Mortality Survey (1963), by Neville Butler and Dennis Bonham, and Perinatal Problems: The Second Report of the 1958 British Perinatal Mortality Survey (1969), by Neville Butler and Eva Alberman.

2. Born to Fail?

The Home and the School (1964) reports James Douglas’s work on the educational trajectories of the 1946 cohort. Douglas continued to document the children’s differing educational trajectories during secondary school in All Our Future (1968), which he authored with Jean Ross and Howard Simpson.

The revival of the 1958 cohort and the wealth of findings on the sweep at age seven are documented in the appendix to the Plowden Report: Children and Their Primary Schools: A Report of the Central Advisory Council for Education (England) (1967). The results were later written up in the books 11,000 Seven Year Olds (1966), by Mia Kellmer Pringle, Neville Butler and Ronald Davie, and From Birth to Seven (1972), by Ronald Davie, Neville Butler and Harvey Goldstein. The Sunday Times magazine article ‘An Unequal Start’ (4 June 1972), by Ronald Davie, summarized the results in the latter book and caused the major embargo break by the British press.

The origins of the National Children’s Bureau and the years during which it housed the 1958 cohort are covered succinctly in 30 Years of Change for Children (1993), edited by Gillian Pugh. I was also fortunate to be able to consult two dusty books at the National Children’s Bureau in London which are stuffed with press clippings about work from the 1958 cohort study during the 1960s, 70s and 80s. These also hold the minutes from the Bureau’s annual general meetings.

The slim book Born to Fail?, by Peter Wedge and Hilary Prosser, is just as powerful now as it was when it was selling out from station bookshops in 1973. It reveals the difficult life trajectories of children born into disadvantage in the second of the British birth cohorts – a story continued in the follow-up book, Children in Adversity (1982), by Peter Wedge and Juliet Essen. A thorough overview of the country’s education system is provided by Education in England: A Brief History (2011), by Derek Gillard (www.educationengland.org.uk/history). For more information on the research programme inspired by Sir Keith Joseph’s speech, see Cycles of Disadvantage (1976), by Michael Rutter and Nicola Madge.

Elsa Ferri’s illuminating report on children of one-parent families in the 1958 cohort is Growing Up in a One-Parent Family (1976). The key studies on the impacts of divorce from the 1958 cohort are summarized in the aforementioned report Now we are 50 (2008), edited by Jane Elliott and Romesh Vaitilingam. For the study showing that differences in children of divorced parents are in evidence before parents separate, see B. J. Elliott and M. P. M. Richards (1991), ‘Children and divorce: educational performance and behaviour before and after parental separation’, International Journal of Law, Policy and the Family 5, 258–76 (1991). A comparison of the impacts of divorce on children in the 1946, 1958 and 1970 cohorts was published as M. Ely, M. P. M. Richards, M. E. J. Wadsworth and B. J. Elliott, ‘Secular changes in the association of parental divorce and children’s educational attainment: evidence from three British birth cohorts’, Journal of Social Policy 28 (3), 437–55 (1999).

The details and results of the 1970 British birth survey are described in British Births 1970 (1975), by Roma Chamberlain, Geoffrey Chamberlain, Brian Howlett and Albert Claireaux.

3. In Sickness and in Health

Accounts of the 1952 London fog can be found in reports from the Meteorological Office (http://www.metoffice.gov.uk/education/teens/case-studies/great-smog) as well as newspaper articles of the time. James Douglas’s work on the lasting effects of air pollution is described in J. W. B. Douglas and R. E. Waller, ‘Air pollution and respiratory infection in children’, British Journal of Preventive and Social Medicine 20, 1–8 (1966), and later publications.

The way that epidemiology came to focus on chronic disease, and the role of adult cohorts in driving that change, is described in A Life Course Approach to Chronic Disease Epidemiology (1997, and its second edition of 2004), edited by Diana Kuh and Yoav Ben-Shlomo – and Chapter 2 in particular (D. Kuh and G. Davey Smith, ‘The life course and adult chronic disease: an historical perspective with particular reference to coronary heart disease’).

The way in which epidemiological studies revealed the link between lung cancer and smoking is covered in R. Doll, ‘Cohort studies: history of the method. I. Prospective cohort studies’, Sozial- und Präventivmedizin 46, 75–86 (2001), a reference already noted above. Other sources include C. White, ‘Research on smoking and lung cancer: a landmark in the history of chronic disease epidemiology’, Yale Journal of Biology and Medicine 63 (1), 29–46 (1990); G. Davey Smith and M. Egger, ‘The first reports on smoking and lung cancer – why are they consistently ignored?’, Bulletin of the World Health Organization 83 (10) (2005); and J. Cornfield et al., ‘Smoking and lung cancer: recent evidence and a discussion of some questions’, Journal of the National Cancer Institute 22, 173–203 (1959), a paper reprinted in International Journal of Epidemiology 38, 1175–91 (2009).

Doll and Hill’s case control study was published as R. Doll and A. B. Hill, ‘Smoking and carcinoma of the lung’, British Medical Journal 2, 739–48 (1950). For the results from the British Doctors’ Study, see R. Doll and A. B. Hill, ‘The mortality of doctors in relation to their smoking habits: a preliminary report’, British Medical Journal 1 (4877), 1451–55 (1954).

The history and impact of the famous Framingham cohort are well told in a review published in the Lancet on the study’s sixty-fifth birthday: S. S. Mahmood et al., ‘The Framingham Heart Study and the epidemiology of cardiovascular disease: a historical perspective’, Lancet 383, 999–1008 (2014).

The story of how the 1958 cohort data helped lead to a consensus that smoking could cause low birth weight is summarized in H. Goldstein, ‘Smoking in pregnancy: some notes on the statistical controversy’, British Journal of Preventive and Social Medicine 31, 13–17 (1977). The key paper from the study was N. R. Butler, H. Goldstein and E. M. Ross, ‘Cigarette smoking in pregnancy: its influence on birth weight and perinatal mortality’, British Medical Journal 2 (5806), 127–30 (1972). For the painfully condescending editorial about pregnant women and smoking, see ‘Smoking, pregnancy and publicity’, Nature 245, 61 (1973). The advertisements featuring a pregnant, smoking woman are in V. Berridge and K. Loughlin, ‘Smoking and the new health education in Britain 1950s–1970s’, American Journal of Public Health 95 (6), 956–64 (2005).

The history of the 1946 cohort told in this chapter, including the MRC’s great debate about what to do with the study when Douglas retired, is explained in M. Wadsworth, ‘Focussing and funding a longitudinal study of health over 20 years: the MRC National Survey of Health and Development from 16 to 36 years’, mentioned above.

Two of the studies from the 1946 cohort that linked respiratory illness in childhood with chronic cough in adults are: J. R. T. Colley, J. W. B. Douglas and D. D. Reid, ‘Respiratory disease in young adults: influence of early childhood lower respiratory tract illness, social class, air pollution and smoking’, British Medical Journal 3 (5873), 195–8 (1973), and K. E. Kiernan, J. R. Colley, J. W. Douglas and D. D. Reid, ‘Chronic cough in young adults in relation to smoking habits, childhood environment and chest illness’, Respiration 33 (3), 236–44 (1976).

The Bedford survey of 1962 and its 25,000 bottles of urine are reported in W. J. H. Butterfield, ‘Diabetes survey in Bedford 1962’, Proceedings of the Royal Society of Medicine 57 (3), 196–200 (1964).

PART TWO: Coming of Age

4. Staying Alive

The difficult years faced by the social sciences and the SSRC described here drew on the previously mentioned source SSRC and ESRC: The First Forty Years (2005).

The account of the years that Neville Butler ran the 1970 cohort in Bristol was based largely on interviews. The publications and funding sources during that period are summarized in J. Elliott and P. Shepherd, ‘Cohort profile: 1970 British Birth Cohort (BCS70)’, International Journal of Epidemiology 35 (4), 836–43 (2006).

The history of the fourth perinatal mortality survey – the one that would have ideally started in 1982 – is based on interviews. Other sources include a plan for the survey provided to me by Jean Golding and a report on the proposal submitted to the DHSS in May 1979, Desirability and Feasibility of a Fourth National Perinatal Survey, a copy of which was given to me by its author, Iain Chalmers. I also consulted the annual reports of the National Perinatal Mortality Unit from its early years, kindly lent to me by Alison MacFarlane.

Iain Chalmers’s studies on the risks and benefits of the increased medicalization of birth are published in I. Chalmers, J. E. Zlosnik, K. A. Johns and H. Campbell, ‘Obstetric practice and outcome of pregnancy in Cardiff residents 1965–73’, British Medical Journal 1 (6012), 735–8 (1976), and I. Chalmers, J. G. Lawson and A. C. Turnbull, ‘Evaluation of different approaches to obstetric care: Part 1’, British Journal of Obstetrics and Gynaecology 83 (12), 92–9 (1976).

The backlash over the increased medicalization of birth is covered in J. Russell, ‘Perinatal mortality: the current debate’, Sociology of Health and Illness 4, 302–19 (1982), and A. Susan Williams’s Women and Childbirth in the Twentieth Century (1997).

Austin Bradford Hill’s randomized controlled trial of streptomycin is reported in ‘Streptomycin treatment of pulmonary tuberculosis’, British Medical Journal 2 (4582), 769–82 (1948). Archie Cochrane’s seminal book Effectiveness and Efficiency: Random Reflections on Health Services (1972) helped change the way that medical treatments are evaluated. An oral history of evidence-based medicine, including an interview with Iain Chalmers and other key figures, is available at http://ebm.jamanetwork.com/.

The questions in the 1982 sweep of the 1946 cohort were made available to me by cohort member David Ward, who kindly allowed me to browse through his files and talked me through his and his parents’ answers.

Information on the International Centre for Child Studies was gathered largely from interviews, as well as a 1982 brochure for the centre and other documents shown to me by Diana Pomeroy and Colleen Daley, who worked closely with Neville Butler. I also went to Ashley Down House, the imposing ex-orphanage building that Butler used as the centre’s headquarters in Bristol.

All the survey instruments from the 1986 sweep of the 1970 cohort, including the leisure diary, are available on the website of the Centre for Longitudinal Studies, http://www.cls.ioe.ac.uk/. Information on the sweep is also available in the UK Data Service as http://dx.doi.org/10.5255/UKDA-SN-3535-2.

A copy of the video recording of the three cohort leaders, Three Generations of Children, made in March 1982, was given to me by Harvey Goldstein. A transcript of the video was published in Paediatric and Perinatal Epidemiology 12, Suppl. 1, 15–30 (1998) – a special issue of the journal dedicated to the memory of Neville Butler.

5. Older and Wiser

A few excerpts from this chapter were previously printed in a feature that I wrote about the 1991 cohort, ‘Coming of age’, Nature 484, 155–8 (2012).

An excellent oral history of the early years of the ALSPAC cohort, recounted by Jean Golding and many others involved, is available as a ‘Witness Seminar’ (May 2011), ‘History of the Avon Longitudinal Study of Parents and Children (ALSPAC), c.1980–2000’ at http://www.histmodbiomed.org/witsem/vol44. An overview of the cohort and its publications is provided by A. Fraser et al., ‘Cohort profile: the Avon Longitudinal Study of Parents and Children: ALSPAC mothers cohort’, International Journal of Epidemiology 42 (1), 97–110 (2013), and A. Boyd et al., ‘Cohort profile: the “Children of the 90s” – the index offspring of the Avon Longitudinal Study of Parents and Children’, International Journal of Epidemiology 42 (1), 111–27 (2013). The cohort team also published a book about the study to mark its twenty-first birthday: Twenty One Years: Our Journey (2012), available to download at http://www.bristol.ac.uk/alspac/go/21st-book/.

A potted history of the Human Genome Project can be found on the websites of two of the major institutions involved, the Wellcome Trust Sanger Institute (http://www.sanger.ac.uk/about/history/hgp/#tabs-1) and the National Human Genome Research Institute (http://www.genome.gov/10001772). In 1990 Marcus Pembrey articulated the case that a birth cohort study would help decipher the human genome in a short letter to Nature: see M. E. Pembrey, ‘Cohort of Genes’, Nature 348, 280 (1990).

The paper from the 1946 cohort which found a correlation between weight at birth and blood pressure at age thirty-six is M. E. J. Wadsworth, H. A. Cripps, R. E. Midwinter and J. R. T. Colley, ‘Blood pressure in a national birth cohort at the age of 36 related to social and familial factors, smoking, and body mass’, British Medical Journal 291 (6508), 1534–8 (1985).

The history of the idea that foetal and child development can influence risk of chronic disease is summarized in the aforementioned chapter D. Kuh and G. Davey Smith, ‘The life course and adult chronic disease: an historical perspective with particular reference to coronary heart disease’, in A Life Course Approach to Chronic Disease Epidemiology (1997), edited by Diana Kuh and Yoav Ben-Shlomo. Other sources include G. Davey Smith and D. Kuh, ‘Commentary: William Ogilvy Kermack and the childhood origins of adult health and disease’, International Journal of Epidemiology 30 (4), 696–703 (2001), and D. Kuh et al., ‘Life course epidemiology and analysis’, in Oxford Textbook of Global Public Health, 6th edition (2015), edited by Roger Detels, Martin Gulliford, Quarraisha Abdool Karim and Chorh Chuan Tan; as well as a slide presentation shared with me by Diana Kuh.

The story of David Barker’s work is based in part on an interview with him in 2013. This history and Barker’s ideas are also well explained in a November 2007 profile of Barker by Stephen S. Hall in the New Yorker magazine at http://www.newyorker.com/magazine/2007/11/19/small-and-thin), and Size Matters: How Height Affects the Health, Happiness, and Success of Boys – and the Men They Become (2006), also by Stephen S. Hall.

For the death atlas, with the green and red maps showing the distribution of heart disease deaths, see Martin J. Gardner et al., Atlas of Mortality from Selected Diseases in England and Wales, 1968–1978 (1984). Barker’s ideas are also explained in D. Almond and J. Currie, ‘Killing me softly: the foetal origins hypothesis’, Journal of Economic Perspectives 25 (3), 153–72 (2011). An overview of the Hertfordshire cohort is in H. E. Syddall et al., ‘Cohort profile: the Hertfordshire Cohort Study’, International Journal of Epidemiology 34 (6), 1234–42 (2005).

Two of Barker’s key publications are D. J. Barker and C. Osmond, ‘Infant mortality, childhood nutrition, and ischaemic heart disease in England and Wales’, Lancet 1 (8489), 1077–81 (1986), and D. J. Barker et al., ‘Weight in infancy and death from ischaemic heart disease’, Lancet 2 (8663), 577–80 (1989).

The history of the Whitehall Study and Whitehall II can be found at http://www.ucl.ac.uk/whitehallII/history. Whitehall II is also the subject of M. Marmot and E. Brunner, ‘Cohort profile: the Whitehall II study’, International Journal of Epidemiology 34 (2), 251–6 (2005).

The links between childhood developmental milestones and later risk of schizophrenia were described in P. Jones, B. Rodgers, R. Murray and M. Marmot, ‘Child development risk factors for adult schizophrenia in the British 1946 birth cohort’, Lancet 344 (8934), 1398–402 (1994).

The study linking menopause to early development is D. Kuh et al., ‘Childhood cognitive ability and age at menopause: evidence from two cohort studies’, Menopause 12, 475–82 (2005).

The book on life course epidemiology is the previously mentioned A Life Course Approach to Chronic Disease Epidemiology (1997), edited by Diana Kuh and Yoav Ben-Shlomo. The ideas are also introduced in Y. Ben-Shlomo and D. Kuh, ‘A life course approach to chronic disease epidemiology: conceptual models, empirical challenges and interdisciplinary perspectives’, International Journal of Epidemiology 31 (2), 285–93 (2002).

The 1991 cohort findings on babies’ sleeping position were published as L. Hunt, P. Fleming and J. Golding, ‘Does the supine sleeping position have any adverse effects on the child?: I. Health in the first six months’, Pediatrics 100 (1), E11 (1997), and C. Dewey, P. Fleming and J. Golding, ‘Does the supine sleeping position have any adverse effects on the child? II. Development in the first 18 months’, Pediatrics 101 (1), E5 (1998).

For the findings of studies showing that eating fish during pregnancy is associated with better eye and cognitive development in children, see C. Williams et al., ‘Stereoacuity at age 3.5 y in children born full-term is associated with prenatal and postnatal dietary factors’, American Journal of Clinical Nutrition 73 (2), 316–22 (2001); J. L. Daniels et al., ‘Fish intake during pregnancy and early cognitive development of offspring’, Epidemiology 15 (4), 394–402 (2004); and J. R. Hibbeln et al., ‘Maternal seafood consumption in pregnancy and neurodevelopmental outcomes in childhood (ALSPAC study): an observational cohort study’, Lancet 369 (9561), 578–85 (2007).

The FTO gene association study was published as T. M. Frayling et al., ‘A common variant in the FTO gene is associated with body mass index and predisposes to childhood and adult obesity’, Science 316, 889–94 (2007).

The study charting and comparing the BMI of the 1946 and 1958 cohorts is L. Li, R. Hardy, D. Kuh, R. Lo Conte and C. Power, ‘Child-to-adult body mass index and height trajectories: a comparison of 2 British birth cohorts’, American Journal of Epidemiology 168 (9), 1008–15 (2008); for the study showing the strength of association between BMI and variants of the genes FTO and MC4R, see R. Hardy et al., ‘Life course variations in the associations between FTO and MC4R gene variants and body size’, Human Molecular Genetics 19 (3), 545–52 (2010).

For an overview of the Boyd Orr cohort, see R. M. Martin et al., ‘Cohort profile: the Boyd Orr cohort – an historical cohort study based on the 65 year follow-up of the Carnegie Survey of Diet and Health (1937–39)’, International Journal of Epidemiology 34 (4), 742–9 (2005). For a more colourful history and pictures of the original handwritten ledgers, see David Blane’s presentation at https://www.ucl.ac.uk/icls/publications/op/index/edit/boydorr.pdf.

George Davey Smith’s career is affectionately documented in a file put together by his colleagues in 2013 called ‘The First One Thousand: Reflections on the Publications of George Davey Smith’, a copy of which was given to me by Davey Smith.

For the study comparing the causal effects of breastfeeding in the 1991 cohort with the Pelotas birth cohorts in Brazil, see M.-J. A. Brion et al., ‘What are the causal effects of breastfeeding on IQ, obesity and blood pressure? Evidence from comparing high-income with middle-income cohorts’, International Journal of Epidemiology 40 (3), 670–80 (2011).

Work using Mendelian randomization to unpick the effects of drinking alcohol during pregnancy is described in L. Zuccolo et al., ‘Prenatal alcohol exposure and offspring cognition and school performance: A “Mendelian randomization” natural experiment’, International Journal of Epidemiology 42 (5), 1358–70 (2013).

The epigenetic study on cord blood samples of children in the 1991 cohort is published as C. L. Relton et al., ‘DNA methylation patterns in cord blood DNA and body size in childhood’, PLoS ONE 7 (3), e31821 (2012). Barker’s study on the placentas of the 1991 cohort is D. Barker et al., ‘Maternal cotyledons at birth predict blood pressure in childhood’, Placenta 34 (8), 672–5 (2013).

The study establishing a link between iodine deficiency in mothers and mental development in children was led by Margaret Rayman at the University of Surrey, UK, and published as S. C. Bath et al., ‘Effect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children: results from the Avon Longitudinal Study of Parents and Children (ALSPAC)’, Lancet 382 (9889), 331–7 (2013).

6. Opening Up

The history of the UK Data Archive at Essex University is described in a publication celebrating its fortieth anniversary: Across the Decades – 40 Years of Data Archiving (2007). Other details on the archive were provided to me by Mike Knight and Jack Kneeshaw, who kindly showed me around the data centre.

John Bynner contributed to The Sexual Behaviour of Young People (1965), under the main authorship of Michael Schofield, and his work on smoking behaviour was published as The Young Smoker: A Study of Smoking among Schoolboys Carried Out for the Ministry of Health (1969).

Bynner’s report on the 1958 cohort data and why it wasn’t being used is Secondary Use of the National Child Development Study: A Report Prepared for the Economic and Social Research Council (1984), a copy of which he kindly gave to me. The data dictionary for the cohort studies is available on the website of the Centre for Longitudinal Studies at http://www.cls.ioe.ac.uk/datadictionary/default.asp.

A mountain of research and publications has emerged from the cohort studies since the early 1990s, most of which could not be covered in this book. However, for an insight into the wealth of findings from the adult sweeps of the 1958 and 1970 cohort studies, see Life at 33 (1993), edited by Elsa Ferri, Twenty-something in the 1990s: Getting on, Getting by, Getting Nowhere (1997), edited by John Bynner, Elsa Ferri and Peter Shepherd, and Changing Britain, Changing Lives (2003), edited by Elsa Ferri, John Bynner and Michael Wadsworth and the publications on the website of the Centre for Longitudinal Studies.

The account of the economists’ work with cohort data is based largely on interviews. The tests taken by the 1970 cohort children at age 22 months and 42 months are available on the Centre for Longitudinal Studies website.

For an accessible explanation of Leon Feinstein’s work, see L. Feinstein, ‘Very early evidence’, CentrePiece 8 (2), 24–30 (2003). His study was published as L. Feinstein, ‘Inequality in the early cognitive development of British children in the 1970 cohort’, Economica 70 (277), 73–97 (2003). The Feinstein graph in this book is based on the one published in that paper. For the paper challenging part of Feinstein’s analysis, see J. Jerrim and A. Vignoles, ‘The use (and misuse) of statistics in understanding social mobility: regression to the mean and the cognitive development of high ability children from disadvantaged homes’, DoQSS Working Paper No. 11–01 (April 2011).

The economists’ research on social mobility is published in a series of papers, of which just a few are mentioned here. For a digestible summary of the work and the ensuing academic debate, see Jo Blanden, ‘Big ideas: intergenerational mobility’, CentrePiece 13 (3), 6–9 (Winter 2008/9).

For the study assessing intergenerational mobility in the 1958 cohort, see L. Dearden, S. Machin and H. Reed, ‘Intergenerational Mobility in Britain’, Economic Journal 107 (440), 47–66 (1997).

For the comparison of social mobility in the 1958 and 1970 cohorts, see J. Blanden, A. Goodman, P. Gregg and S. Machin, ‘Changes in Intergenerational Mobility in Britain’, in Miles Corak (ed.), Generational Income Mobility in North America and Europe (2004), and J. Blanden and S. Machin, ‘Up and down the generational income ladder in Britain: past changes and future prospects’, National Institute Economic Review 205, 101–17 (2008).

For the work showing a strengthening relationship between parental income and children’s progression in education, see J. Blanden, P. Gregg and L. Macmillan, ‘Accounting for intergenerational income persistence: non-cognitive skills, ability and education’, Economic Journal 117, C43–60 (2007).

For John Goldthorpe’s position on the debate, see J. Goldthorpe, ‘Understanding – and misunderstanding – social mobility in Britain: the entry of the economists, the confusion of politicians and the limits of educational policy’, Journal of Social Policy 42 (3), 431–50 (2013); and the analysis of social mobility across four birth cohorts is E. Bukodi, J. H. Goldthorpe, L. Waller and J. Kuha, ‘The mobility problem in Britain: new findings from the analysis of cohort data’, British Journal of Sociology 66 (1), (2015). The economists’ six-years-in-the-making response is J. Blanden, P. Gregg and L. Macmillan, ‘Intergenerational persistence in income and social class: the effect of within-group inequality’, Journal of the Royal Statistical Society 176 (2), 541–63 (2013).

The report examining the family income and cognitive ability in childhood of those who later enter top professions was L. Macmillan, Social Mobility and the Professions (2009) at http://www.bristol.ac.uk/media-library/sites/cmpo/migrated/documents/socialmobility.pdf.

The cohort work on literacy and numeracy is summarized by John Bynner in ‘Skills and Lifelong Learning’, Chapter 9 of Now we are 50 (2008), and in a report by David Budge, The Impact of Adult Literacy and Numeracy Research Based on the 1970 British Cohort Study (2014), available on the website of the Centre for Longitudinal Studies. Much more detail is provided in a series of reports on the website of the National Research and Development Centre for Adult Literacy and Numeracy (http://www.nrdc.org.uk/). For example, see J. Bynner, and S. Parsons, New Light on Literacy and Numeracy (2006).

The Moser report is A Fresh Start: Improving Literacy and Numeracy. The Report of the Working Group Chaired by Sir Claus Moser (1999).

John Bynner’s work tracing the trajectories of adults with poor basic skills is summarized in S. Parsons and J. Bynner, Illuminating Disadvantage: Profiling the Experiences of Adults with Entry Level Literacy or Numeracy over the Lifecourse (2007). It is also discussed in J. Bynner, ‘Never too early, never too late’, in Adults Learning (2008).

Glen Elder’s book, influential in the development of life course theory, is Children of the Great Depression (1974), which was extended and updated in a twenty-fifth anniversary edition published in 1999.

Jo Blanden’s report showing the importance of parental interest and engagement in children’s trajectories is ‘Bucking the Trend’: What Enables Those who are Disadvantaged in Childhood to Succeed Later in Life? (2006) at dera.ioe.ac.uk/7729/.

PART THREE: Coming Full Circle

7. The Millennium Children

The beginnings of the millennium cohort were pieced together mostly from interviews, as well as two reports on the history and origins of the study: The Millennium Cohort Study Annual Report to ESRC & ONS (2001), provided to me by Heather Joshi, and Millennium Cohort Study: First, Second, Third and Fourth Surveys: A Guide to the Datasets (2012), edited by Kirstine Hansen and available on the website of the Centre for Longitudinal Studies.

For the results from the early years of the millennium cohort children, see S. Dex and H. Joshi (eds), Children of the 21st Century: From Birth to Nine Months (2005), and K. Hansen, H. Joshi and S. Dex (eds), Children of the 21st Century: The First Five Years (2010). For an overview of the millennium cohort study, see R. Connelly and L. Platt, ‘Cohort profile: UK Millennium Cohort Study (MCS)’, International Journal of Epidemiology 43 (6), 1719–25 (2014).

The economists’ analysis of the cognitive scores of the millennium cohort children at the ages of three and five is published in J. Blanden and S. Machin, ‘Intergenerational inequality in Early Years assessments’, a chapter in Children of the 21st Century: The First Five Years. Ricardo Sabates and Shirley Dex’s study of risks in millenium cohort children is in the Institute of Education publication Multiple Risk Factors in Young Children’s Development (2012).

James Douglas’s analysis of the links between interested parents and better progress through school is in Chapter 7 of The Home and the School (1964). The cohort study following 3,000 children is the Effective Pre-School, Primary and Secondary Education (EPPSE) research project and its results are published in a series of reports available at http://www.ioe.ac.uk/research/153.html. For the study of bedtimes and behaviour in millennium cohort children, see Y. Kelly, J. Kelly and A. Sacker, ‘Changes in bedtime schedules and behavioral difficulties in 7 year old children’, Pediatrics 132 (5), e1184–93 (2013).

For the millennium cohort study arguing that both poverty and parenting matter, see K. E. Kiernan and F. K. Mensah, ‘Poverty, family resources and children’s early educational attainment: the mediating role of parenting’, British Educational Research Journal 37 (2), 317–36 (2011). For a useful review on parenting and education, see the report by Charles Desforges and Alberto Abouchaar, The Impact of Parental Involvement, Parental Support and Family Education on Pupil Achievements and Adjustment: A Literature Review (Research Report 433) (2003).

The findings on childhood obesity in the millennium cohort are summarized in L. J. Griffiths, S. S. Hawkins, T. Cole, C. Law and C. Dezateux, ‘Childhood overweight and obesity’, in Children of the 21st Century: The First Five Years. For the study on working mothers and childhood obesity, see S. S. Hawkins et al., ‘Maternal employment and early childhood overweight: findings from the UK Millennium Cohort Study’, International Journal of Obesity 32, 30–38 (2008). For the study in which the children wore accelerometers, see L. J. Griffiths et al., ‘How active are our children? Findings from the Millennium Cohort Study’, BMJ Open 3, e002893 (2013).

The cohort work on summer-born children is largely summarized in a report published by the Institute for Fiscal Studies: C. Crawford, L. Dearden and E. Greaves, Does When You are Born Matter? The Impact of Month of Birth on Children’s Cognitive and Non-cognitive Skills in England (2011).

For the study examining the causal effects of breastfeeding using the millennium cohort, see E. Fitzsimons and M. Vera-Hernandez, ‘Food for thought? Breastfeeding and child development’, Institute for Fiscal Studies Working Paper W13/31 (2013).

The changing role of women in the workplace has been studied extensively using the British birth cohorts and is beyond the scope of this book. It is covered in Now we are 50 (2008) and Unequal Pay for Women and Men: Evidence from the British Birth Cohort Studies (1998), by H. Joshi and P. Paci. Some of the work on the financial returns to education is also summarized in Now we are 50.

For an overview of major birth and child cohort studies, see C. Pirus and H. Leridon, ‘Large child cohort studies across the world’, Population 65 (4), 575–629 (2010). The annual international meeting on longitudinal studies is the aforementioned conference of the Society for Longitudinal and Life Course Studies (http://www.slls.org.uk/).

The challenges of starting new birth cohorts are well described in D. A. Lawlor, A.-M. Nybo Andersen and G. D. Batty, ‘Birth cohort studies: past, present and future’, International Journal of Epidemiology 38 (4), 897–902 (2009). An inventory of birth cohorts is available at http://www.birthcohorts.net/bch2.

Information on the US National Children’s Study is online at https://www.nichd.nih.gov/research/NCS/Pages/default.aspx. The plans for the study were outlined in A. E. Guttmacher, S. Hirschfeld and F. S. Collins, ‘The National Children’s Study – a proposed plan’, New England Journal of Medicine 369 (20), 1873–5 (2013). The story of the study’s origins and challenges is well told in Jocelyn Kaiser, ‘The Children’s Study: unmet promises’, Science 339 (6116), 133–6 (2013).

A lovely brochure celebrating the sixty-fifth birthday of the 1946 cohort is available at http://www.nshd.mrc.ac.uk/nshd/65th-birthday-brochure/ and a gallery of all the birthday cards sent to the cohort members since the practice started in 1962 can be viewed at http://www.nshd.mrc.ac.uk/nshd/birthday-card-gallery/. Some interviews from the London birthday party are part of an NPR radio piece on the cohort available at http://www.npr.org/blogs/health/2011/12/23/144192370/poked-and-prodded-for-65-years-in-the-name-of-science.

For the paper showing correlations between the 1946 cohort’s childhood socioeconomic position and performance in the medical MOTs in their sixties, see L. Hurst et al., ‘Lifetime socioeconomic inequalities in physical and cognitive aging’, American Journal of Public Health 103 (9), 1641–8 (2013).

For the study examining mortality in the cohort, see D. Kuh et al., ‘Do childhood cognitive ability or smoking behaviour explain the influence of lifetime socio-economic conditions on premature adult mortality in a British post war birth cohort?’, Social Science and Medicine 68 (9), 1565–73 (2009). And for the tally of medical conditions suffered by each 1946 cohort member, see M. B. Pierce et al., ‘Clinical disorders in a post war British cohort reaching retirement: evidence from the first national birth cohort study’, PLoS One 7 (9), e44857 (2012).

8. Bridging the Divides

The impressive scientific facilities supported by the Large Facilities Capital Fund can be found in a roadmap document from 2010 at http://www.rcuk.ac.uk/Publications/policy/lfr/.

A copy of the four-page pitch to the fund for a research laboratory for the birth cohort studies was given to me by Peter Elias. The case for a new British birth cohort and for the scientific importance of cohort studies as a whole was also articulated in influential reports by the think tank Longview, available at http://www.slls.org.uk/#!longviewreports/c8a5. For an earlier effort to coordinate research across cohort studies, as part of a project called Healthy Ageing across the Life Course (HALCYON), see http://www.halcyon.ac.uk/.

The Pinch: How the Baby Boomers Took Their Children’s Future – and Why They Should Give it Back (2011), by David Willetts, earned the author a review as a ‘one man think tank’. A copy of his March 2011 speech announcing the funding of the 2012 birth cohort is available at https://www.gov.uk/government/speeches/the-arts-humanities-and-social-sciences-in-the-modern-university.

The 1915 book Maternity Letters from Working Women, by Margaret Llewelyn Davies, is as powerful now as it was one hundred years ago and offers a compelling insight into the past conditions in which women bore and frequently lost children. The website for Life Study is http://www.lifestudy.ac.uk/homepage.

For the cohort study documenting the impact of air pollution on children living near a freeway, see W. J. Gaudernman et al., ‘Effect of exposure to traffic on lung development from 10 to 18 years of age: a cohort study’, Lancet 369 (9561), 571–7 (2007).

The birth cohorts laboratory was launched under the name CLOSER (Cohort and Longitudinal Studies Enhancement Resources) in 2013 and details can be found at http://www.closer.ac.uk/. The adopted cohort of around 16,000 children born in 1989–90 was known as the Longitudinal Study of Young People in England, or LSYPE, but was rebranded by the cohort scientists as Next Steps. Information can be found at http://www.cls.ioe.ac.uk/page.aspx?&sitesectionid=1246&sitesectiontitle=Welcome+to+Next+Steps+(LSYPE).

For the study comparing body weights across several cohorts, see W. Johnson, L. Li, D. Kuh and R. Hardy, ‘How has the age-related process of overweight or obesity development changed over time? Co-ordinated analyses of individual participant data from five United Kingdom birth cohorts’, PLoS Medicine 12 (5), e1001828 (2015).

The preliminary results on bodyweight in the 1970 birth cohort were published by the Centre for Longitudinal Studies in a report by Alice Sullivan and Matt Brown, Overweight and Obesity in Mid-life: Evidence from the 1970 Birth Cohort Study at Age 42 (2013).

The first findings from the sweep of the 1970 cohort at age 42 were reported in a series of papers in Longitudinal and Life Course Studies 6 (2) (2015).

The correlation between childhood reading for pleasure and later educational performance is reported in A. Sullivan and M. Brown, ‘Social inequalities in cognitive scores at age 16: the role of reading’ (2013), available on the website of the Centre for Longitudinal Studies.

All other reports, studies and plans for future sweeps on the 1958, 1970 and millennium cohorts can be found on the website of the Centre for Longitudinal studies at http://www.cls.ioe.ac.uk.

Epilogue: Where are They Now?

For the study connecting physical tasks in middle age with mortality, see R. Cooper et al., ‘Physical capability in mid-life and survival over 13 years of follow-up: British birth cohort study’, British Medical Journal 348, g2219 (2014).

The famous marshmallow experiments are described in The Marshmallow Test: Mastering Self-Control (2014) by Walter Mischel. Evidence for the importance of social and emotional skills across the life course is provided in ‘Social and emotional skills in childhood and their long-term effects on adult life’, by A. Goodman, H. Joshi, B. Nasim and C. Tyler (2015), available at http://www.eif.org.uk/wp-content/uploads/2015/03/EIF-Strand-1-Report-FINAL1.pdf. One study showing the lasting impacts of early psychological health is A. Goodman, R. Joyce and J. P. Smith, ‘The long shadow cast by childhood physical and mental health problems on adult life’, PNAS 108 (15), 6032–7 (2011).