National Survey of Health Development

The National Survey of Health and Development (NSHD) is a long-running longitudinal birth cohort study conducted in the United Kingdom under the auspices of the Medical Research Council (MRC). It follows the lives of individuals born in Britain during a single week in March 1946 and is widely recognised as the longest continuously running major birth cohort study in the world. The survey occupies a central position in life course epidemiology and social science research, providing unparalleled insights into human development, health, and ageing across the entire lifespan.

Origins and Early Objectives

The study began in 1946, less than a year after the end of the Second World War, under the direction of Dr James W. B. Douglas. Initially known as the 1946 Birth Cohort Study, it was promoted by the Population Investigation Committee with support from the Royal College of Obstetricians and Gynaecologists. Early funding was provided by the Nuffield Foundation and the National Birthday Trust Fund.
The original survey was designed as a one-off investigation to address pressing demographic and medical questions of the time. These included concerns about the long-term decline in Britain’s fertility rate, the financial burden of childbirth, and the effectiveness of midwifery and obstetric services. At the time of its conception, the organisers were unaware that the study coincided with the beginning of the post-war baby boom, which rendered some of the original fertility questions less relevant.

Initial Data Collection and Findings

The survey commenced with interviews of 13,687 mothers who had given birth in England, Wales, and Scotland during one week in March 1946, representing approximately 91 per cent of all births in that period. This exceptionally high coverage provided a robust and nationally representative dataset.
Early findings revealed stark inequalities in birth outcomes across social classes. One of the most striking results was that babies born to mothers in the lowest social class were approximately 70 per cent more likely to be stillborn than those born to mothers in the highest social class. These findings highlighted profound social inequalities in maternal and infant health and contributed directly to policy debates in the post-war period.
The evidence generated by the study informed planning decisions surrounding the establishment of the National Health Service (NHS) in 1948, particularly in relation to maternity care and access to medical services.

Transition to a Longitudinal Study

Following its initial success, the study was transformed from a one-off survey into a longitudinal investigation. The cohort was reduced to a sample of 5,362 children, excluding twins and illegitimate births, reflecting social and research norms of the period. These individuals were followed up at regular intervals throughout childhood and adulthood.
The expanded objectives of the study included examining the impact of the newly established NHS on population health and exploring how factors such as social class, education, family environment, and childhood illness influenced physical, cognitive, and emotional development. Over time, the survey evolved into a comprehensive life course study, tracking participants from birth into later life.

Development into a Study of Ageing

By the late twentieth and early twenty-first centuries, the NSHD had become a major resource for research on ageing. As cohort members entered midlife and older age, the focus of data collection broadened to include chronic disease, cognitive decline, mental health, physical capability, and healthy ageing.
As of 2016, the study had transitioned fully into an interdisciplinary investigation of ageing, examining how early life circumstances, education, work, lifestyle, and health behaviours influence outcomes in later life. The regularly updated dataset also allows for detailed comparisons with later British birth cohort studies and international longitudinal research.

Scientific Mission and Research Aims

The mission of the NSHD is to realise its scientific potential as a world-class interdisciplinary life course study. Its core aims include:

• Scientific discovery of life course influences on normal and healthy ageing
• Transfer of knowledge to policymakers, health practitioners, and research users
• Promotion of healthy ageing across populations

The study’s breadth and duration enable researchers to identify critical periods in development, assess cumulative advantages and disadvantages, and explore the long-term consequences of social and biological factors.

Institutional History and Administration

Over its long history, the NSHD has been based at several leading academic institutions. In its early years, it was housed at the London School of Economics under the direction of Dr James W. B. Douglas. It later moved to the University of Bristol and subsequently to the Department of Epidemiology and Public Health at University College London, where it was directed by Professor Michael Wadsworth.
In 2008, the MRC Unit for Lifelong Health and Ageing was established to support and manage the study. By 2016, the NSHD was operating under this unit, based in Bloomsbury, London. At that time, the unit was directed by Professor Diana Kuh. The unit provides a stable institutional framework for ongoing data collection, analysis, and dissemination.

Cohort Engagement and Milestones

Maintaining long-term participation has been a defining feature of the NSHD. Members of the 1946 birth cohort have remained actively engaged with the study for decades. Significant milestones have been marked by cohort-wide events, including 65th and 70th birthday celebrations held in 2011 and 2016 respectively. These events symbolise both the continuity of the study and the strong relationship between researchers and participants.