Study members became part of the cohort at birth and have been followed throughout their lives. The 1970 birth survey had a medical focus but the scope of the study has broadened over time. Childhood sweeps at 5, 10 and 16 tracked physical, social and educational development through childhood and into adolescence. Adult sweeps have gathered information about all of the key domains of life including housing; cohabiting relationships; fertility and births; children and wider family; family income and wealth; economic activity; lifelong learning; health and health behaviours and social participation.
By following study members over time BCS70 makes it possible to examine how early life experiences can affect later life circumstances. As such the data from BCS70 has become a hugely important resource for research. BCS70 is the third of four studies in Britain’s world-renowned series of birth cohort studies, following the 1946 and 1958 birth cohorts and preceding the Millennium cohort study. The existence of the different cohorts allows for the study of generational change and its impact on social, economic and health outcomes.
What data has been collected
BCS70 began as the British Births Survey (BBS), with information collected about the births and social circumstances of over 17 000 babies born in England, Scotland, Wales, and Northern Ireland. The focus of the survey was to investigate the factors associated with good and poor health amongst new mothers and babies.
Childhood follow-ups took place at 5 (1975), 10 (1980) and 16 (1986). These follow-ups sought to track all aspects of physical, social, emotional and cognitive development. On each occasion, information was collected via interviews with parents, class teacher and head-teacher questionnaires, questionnaires and assessments completed by study members themselves and medical examinations.
Adult follow-ups have taken place at 26, 30, 34, 38, 42, 46 and the Age 51 sweep is currently in the field. Throughout adulthood the study has covered a wide range of topic areas, many of which are asked at each sweep in order to measure changes over time. Questions and topic areas are also adapted according to the life stage of cohort members at the time of individual surveys. Core themes topics include:
- Household composition
- Family including partners and children
- Housing
- Employment/Economic activities
- Income and wealth
- Education
- Cognition
- Health, wellbeing and lifestyle
- Identity, attitudes, social and political participation
The Age 46 survey included a nurse visit where a full range of biomeasures were collected including blood samples which were analysed for a range of analytes. Consent was collected to extract DNA and the samples are currently being genotyped which will facilitate genetic research. Participants were also asked to wear a thigh-worn accelerometer for 7 days to track levels of physical activity.
The most recent survey was planned to launch in 2020, when participants were aged 50 but was delayed by the pandemic. Instead, along with participants in four other longitudinal studies, BCS70 participants were asked to complete a series of three web surveys throughout 2020 to 2021, which sought to understand the impact of COVID-19 on participant’s lives. The ‘Age 50’ survey – a 75 minute face-to-face survey, was then launched in November 2021 and is currently in the field.
Cohort members have been asked for consent to link survey data with health and economic records held by the NHS, DWP and HMRC. Hospital Episode Statistics have been linked, and are available via the UK Data Archive.
Who is in the cohort?
Participants are survivors from the original sample of over 17 000 births, all born in Britain during one week in 1970. During childhood, cohort members were traced through schools and immigrants born in the reference week were invited to join the study. Throughout the course of the study continued efforts have been made to keep in touch with participants and to trace them when they move, but losing contact with participants has been the major source of attrition over the years.
Just over 8,500 took part in the most recent major wave of data collection at Age 46 (in 2016). Selective attrition has resulted in the achieved sample slightly over-representing those with advantaged childhood socioeconomic background and women. However, CLS have been at the forefront of the development of new approaches to addressing bias in analyses of longitudinal data and recent work has shown that data from earlier waves can be used to successfully restore sample representativeness.
What has it found?
BCS70 data is used extensively for research in the social and health sciences. To date over 1,000 publications have used BCS70 data. The CLS website has a searchable bibliography containing details of all of the publications using BCS70 data that we know about: .
Evidence from BCS70 has had wide-reaching influence on policies and services across health, children’s services, education and skills, social mobility, work and pay.
For example, findings showing the BCS70’s generation’s relative lack of social mobility has informed successive government strategies to help people up the social ladder. It has also been used alongside other cohorts to track the rise of the obesity across generations, which helped set the stage for the 2016 government child obesity strategy.
BCS70 has influenced provision of children’s services in the UK and abroad by providing some of the most robust evidence on the importance of nurseries and playgroups, extracurricular activities, and reading for pleasure to children’s long-term development. Findings from the study on adults’ basic literacy and numeracy skills led to the creation of the Skills for Life programme, which helped over 5.7 million adult learners improve their basic reading, writing and maths.
Most recently, BCS70 has been one of several studies directly informing the government and NHS response to the Covid-19 pandemic through the National Core Studies Programme, led by Sir Patrick Vallance, Government Chief Scientific Advisor.
Evidence from the study has highlighted the impact of the pandemic on the impact of lockdowns on physical and mental health, work and finances, as well as disruptions to healthcare.
More information on the latest research based on BCS70 can be found on the CLS website.
How can I access the data?
Most BCS70 data can be accessed via the UK Data Service. Some data which is more disclosive is only available via Special Licence or via application to the CLS Data Access Committee.
Where can I found out more?
The CLS website provides detailed documentation for researchers and information on research projects and publications arising from the study .
We run a range of training workshops and webinars, designed to help researchers use BCS70 data (and data from the other studies that we run).
You can follow CLS on Twitter: @CLScohorts.
Acknowledgement
We are deeply grateful for the contribution that the 1970 cohort members have made over more than fifty years. We thank the ESRC for our core-funding.
Author Biographies: Carole Sanchez is the BCS70 Survey Manager, Matt Brown is Senior Survey Manager and George Ploubidis is Professor of Population Health and Statistics and Principal Investigator of the National Child Development Study and 1970 British Cohort Study at the Centre for Longitudinal Studies.