Centre for Longitudinal Studies

BCS70 Age 46 Biomedical Sweep

Year
Age
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1970
Birth
1975
5
1980
10
1986
16
1996
26
2000
30
2004
34
2008
38
2012
42
2016
46
2021
51
2026
56
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Sweep details Special features at age 46 Documentation More related content

Sweep details

Sweep status Completed
Dates July 2016 – July 2018
Age 46-48
Achieved sample 8,581 (cohort members)
Respondents Cohort members
Fieldwork agency NatCen Social Research
Survey mode Face to face (interviewers and nurses)
Data access

Main dataset available via the UK Data Service [SN 8547]. Visit the UK Data Service website to access the data.
Description

The Age 46 Sweep involved many data collection elements, including a full range of bio-measures administered by a nurse. The inclusion of objective measures of health will allow researchers to assess the longitudinal predictors of health in mid-life. Many of the measures were included in the NCDS age 44 biomedical sweep, which took place in 2002-03 when study members were aged 44/45 which will allow for cross-cohort comparisons.

A full list of the data collection elements is provided below:

  • 45-minute core interview – topics covered include: relationships, children, parents, place of residence, economic activity, income, qualifications and training, physical and mental health, smoking, drinking, exercise
  • Cognitive assessments – immediate and delayed word recall, letter cancellation and animal-naming tasks
  • Paper self-completion questionnaire – topics covered include physical health, mental health and well-being, physical activity, and leisure activities
  • Anthropometric measurements (height, weight, body-fat, waist/hip circumference)
  • Blood pressure measurement
  • Grip strength assessment
  • Balance assessment
  • Blood sample collection
  • Activity monitor
  • Online dietary diary

Webinar: Introduction to the Age 46 Sweep

Visit the CLS bibliography

Our online bibliography is an excellent resource for finding publications based on data from the 1970 British Cohort Study as well as from our other three cohort studies. It includes over 5,000 publications and is searchable by study, year, author, journal name, title and abstract.

Special features at age 46

Collection of blood samples

Blood samples were collected from all willing participants, with cholesterol and glycated haemoglobin being measured.

Levels of cholesterol (total and high density lipoproteins (HDL)), a major risk factor for cardiovascular disease (CVD) and glycated haemoglobin, associated with the risk of diabetes, were measured. The remaining blood being stored for further analyses. The data collected will allow researchers to examine the links between social factors and these important biomarkers. Participants have also been asked for their consent to extract DNA from their stored blood, which will enable genetic research to be undertaken in the future.

Diet

Cohort members were asked to complete an online questionnaire detailing all they ate and drank in a 24-hour period.

The Age 46 Sweep collected detailed information about diet by asking participants to complete the OxfordWebQ, an online questionnaire developed by the Cancer Epidemiology Unit at the University of Oxford to measure diet in large-scale studies. The questionnaire has been used in UK Biobank, the Million Women Study and the European Prospective Investigation into Cancer and Nutrition (EPIC) Study. Participants were asked to record all that they ate and drank in the 24-hour period prior to the day of completion. The questionnaire asked 21 screener questions covering major food groups, and positive responses are followed up with more detailed questions about particular food and beverage types. Nutrient intakes are automatically calculated by multiplying the quantity of each food consumed by its nutrient composition. Respondents are asked to complete the questionnaire about two randomly allocated days in the week following their visit (one week day and one day at the weekend). The data collected will allow for detailed exploration of the role of diet in determining an individual’s health in mid-life.

Activity monitoring

Cohort members were asked to wear an activity monitor for 7 days to collect detailed objective measures of physical activity.

Physical activity is recognised as one of the most important lifestyle risk factors for cardiovascular disease and other health problems. Detailed objective measures of physical activity were collected as part of the Age 46 Sweep by asking participants to wear an ‘ActivPal’ device for the seven days following their nurse visit. The device is waterproofed and attached to the thigh so can be worn continuously and will characterise patterns of both sedentary and physical activity time over a full week. The data collected will allow researchers to examine the influence of early life social and behavioural factors on physical levels in mid-life. It will provide a contemporary mid-life exposure measure to predict future CVD outcomes and trajectories in functional decline, and allow for detailed examination of the associations between sedentary time and other cardio-metabolic risk biomarkers.

Objective anthropometric measurements

For the first time since childhood, BCS70 is objectively measuring height and weight.

Obesity is a major health concern and research using BCS70 has already played a major role in furthering our understanding of the causes and consequences of being overweight. However, throughout adulthood, BCS70 has relied on participants self-reporting their height and weight which will clearly be less accurate than objective measurements. In addition to height and weight, nurses measured body fat, waist circumference and hip circumference. Together these measurements will provide an invaluable resource for further research into the lifestyle factors leading to obesity and overweight in mid-life and the ongoing consequences for future health.

Documentation

  • User guides
  • Questionnaires
  • Technical reports
  • Data notes
  • Additional
User guides

User guide: Causal inference in the CLS cohort studies

This user guide provides an overview of the possibilities for causal inference in the CLS cohort studies. Specifically, this guide provides data users with background on the problem of causal inference in observational data; details attributes of CLS’s cohorts that can support causal inference; and outlines an extensive set of methods and research designs that can be used to estimate causal effects in CLS’s cohort data.

Date published: 06/10/2026
PDF: 3,25 MB

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BCS70 Age 46 Survey User Guide

User guide for the BCS70 age 46 biomedical survey dataset.

Date published: 27/07/2023
PDF: 489,83 KB

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Harmonised indicators of self-reported asthma in five British cohort studies User Guide

This user guide documents the harmonised indicators of all self-reported measures related to asthma in five British cohort studies: the MRC National Survey of Health and Development (NSHD), the 1958 National Child Development Study (NCDS), the 1970 British Cohort Study (BCS), Next Steps, and the Millennium Cohort Study.

Date published: 18/07/2025
PDF: 531,79 KB

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Harmonised indicators of self-reported diabetes in five British cohort studies User Guide

This user guide documents the harmonised indicators of all self-reported measures related to diabetes in five British cohort studies: the MRC National Survey of Health and Development (NSHD), the 1958 National Child Development Study (NCDS), the 1970 British Cohort Study (BCS), Next Steps, and the Millennium Cohort Study.

Date published: 18/07/2025
PDF: 486,86 KB

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Fertility histories in four British cohort studies User Guide

This user guide accompanies the deposit of datasets on the Cohort Members (CM) fertility histories in four UK cohort studies: MRC National Survey of Health and Development (NSHD), the 1958 National Child Development Study (NCDS), the 1970 British Cohort Study (BCS), and Next Steps.

Date published: 18/07/2025
PDF: 455,26 KB

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Handling mode effects in the CLS cohort studies user guide (Nov 2024)

A user guide which provides guidance and recommendations for handling mode effects in CLS’ cohort studies through applied examples, using data from the National Child Development Study (NCDS) and Next Steps.

Date published: 26/11/2024
PDF: 2,3 MB

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BCS70 Age 46 Survey – Accelerometry User Guide

Accelerometry user guide for the BCS70 age 46 biomedical survey dataset

Date published: 27/03/2020
PDF: 741,83 KB

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BCS70 Age 46 Survey Secure Access Geographical Identifiers User Guide

User guide for the BCS70 Age 46 Survey Secure Access Geographical Identifiers

Date published: 03/10/2019
PDF: 165,91 KB

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Handling missing data in the CLS cohort studies – User Guide

This user guide aims to describe and illustrate a straightforward approach to missing data handling, while detailing some more general considerations around missing data along the way.

Updated: Version 2 on March 2026

Date published: 03/06/2024
PDF: 830,64 KB

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Questionnaires

BCS70 Age 46 follow up – summary of questionnaire content

Date published: 06/06/2019
PDF: 207,42 KB

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BCS70 Age 46 Biomedical Sweep: interview questionnaire

Questionnaire used in the age 46 interview.

Date published: 28/01/2019
PDF: 1,31 MB

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BCS70 Age 46 Biomedical Sweep: self-completion questionnaire

The self-completion questionnaire completed by cohort members for the Age 46 sweep.

Date published: 01/08/2017
PDF: 216,88 KB

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Technical reports

BCS70 Age 46 Survey – Technical Report

This report provides an account of the design, development and conduct of the Age 46 Survey.

Date published: 01/10/2018
PDF: 1,01 MB

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BCS70 Age 46 Survey – Technical Report. Appendix A: Documents

Date published: 01/10/2018
PDF: 5,68 MB

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BCS70 Age 46 Survey – Technical Report. Appendix B: Nurse protocols

Date published: 01/10/2018
PDF: 1,34 MB

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Data notes

No material of this type is available.

Additional

BCS70 Age 46 Survey Derived Variables User Guide

User guide for the BCS70 Age 46 Survey Derived Variables

Date published: 03/10/2019
PDF: 345,24 KB

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BCS70 Ethical Review and Consent

Review of Ethical procedures used for each Sweep of BCS70.

Date published: 01/01/2019
PDF: 4,18 MB

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