Tuesday 16th July
Wednesday 17th July
Thursday 18th July
Friday 19th July
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Collection and analysis of biological data in health surveys: developing best practice 1 |
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| Convenor | Miss Samantha Clemens (Head of the Health and Wellbeing Team) |
| Coordinator 1 | Miss Barbara Schaan (Munich Center for the Economics of Aging, Max Planck Institute for Social Law and Social Policy) |
| Coordinator 2 | Mrs Heidi Guyer (Survey Research Center, University of Michigan) |
Biological measures can add a lot to survey data, enabling us to find out things about participants that cannot be collected through survey questions. These biomeasures encompass a range of biological, anthropometric, functional, and sensory measurements. Examples are height, weight or blood pressure. There have been innovative developments in the collection of biomeasures for example in the study of epigenectics. Integrating biomeasures into surveys has great potential including the estimation of prevalence of disease in a non-clinical population, the detection of undiagnosed conditions, and provision of objective measures compared with self-reported measures.
The collection of biomeasures often involves the development of detailed protocols about when, where, how and by whom the measurements can be taken to ensure that the resulting data are of good quality. Measures may be carried out in participants' homes or at a clinic and they may be collected by a survey interviewer or a trained medical specialist. Often, multiple approaches are used taking into consideration the requirements of the study, measures of interest, cost, and demographics of the study population. Researchers must consider the implications of taking biomeasures at every stage of the survey including ethical implications and the impact on training, pretesting, data collection, data quality, sample shipment, informed consent and response rates.
This session aims to share best practice and explore challenges in collecting biological data in health surveys. We invite papers which describe (but need not be restricted to) the following related to health surveys with biological measurements:
1. Innovations in collecting and analysing biomeasures
2. The design of protocols for complex biomeasures
3. Evaluations of using different protocols
4. Collecting biomeasures for special populations
5. Using biomeasures to validate self-reported health measurements
6. Applying biomeasures for the analysis of social gradients in health and cross-country comparisons in health
INTRODUCTION
We designed a survey to provide data to establish progress towards meeting England's Department of Health's target to reduce the population average of dietary salt intakes to no more than 6g per day. The aim of the study was to collect useable 24-hour urine samples from 600 respondents, representative of the population aged 19 to 64 years living in England.
METHODS
Participants were initially recruited via Random Digit Dialling, followed by a nurse visit. A detailed urine collection protocol was explained to and followed by the participant, after which nurses returned to take two sub-samples from the 24-hour urine sample which were despatched to the lab for analysis.
Completeness was determined by excretion of PABA (p-aminobenzoic acid) or by participant record. Urinary sodium excretion was used to estimate dietary salt intake.
RESULTS
In total, 713 urine samples were processed, of which 77% (547) were 'complete' and therefore used in the analysis.
The mean estimated salt intake for adults aged 19 to 64 years was 8.1g per day, with men having a mean estimated intake of 9.3g per day and women having a mean estimated intake of 6.8g per day. Overall, 70% of participants had a daily intake of salt higher than the recommended maximum of no more than 6g per day; 80% of men and 58% of women exceeded this recommendation.
A number of sodium studies have been carried out since 2000/01. A trend analysis using these studies showed
Aims:
The National Diet and Nutrition Survey (NDNS) is a nationally representative household survey of adults and children. Its purpose is to provide detailed information on the diet and nutritional status of people in the United Kingdom. The survey includes the collection of blood samples from children aged 1.5 to 10 years. Given the challenging nature of taking bloods from young children for research purposes the project team aimed to develop a robust protocol to encourage participation whilst minimising participant risk.
Methods:
Written consent for blood sampling was obtained from the parent or guardian and oral consent from the child (written assent where able).
Several components are highlighted to optimise response:
-Child friendly information leaflets.
-Option to have a local anaesthetic (Ametop gel) or a vapo-coolant (Cryogesic spray) applied to the venepuncture site.
-Venepuncture was conducted in children's homes by specialist nurses or phlebotemists with paediatric experience.
-Parents received a copy of their child's clinically relevant blood results.
-A £15 token of appreciation was sent to participants.
Results:
By implementing robust protocols and procedures, it was possible to collect blood samples from children participating in a household survey. In years 1 to 3 (combined) of NDNS 25% of those aged 1.5 to 10 years who were visited by a nurse provided a blood sample. Future years of the survey will see further innovations to optimise response such as the development of a cartoon strip to help prepare children for the blood sample and reduce anxiety.
Background
Testosterone is linked to many aspects of health and ageing, including sexual health and sexual function. Measuring testosterone on a large probability sample survey would provide an opportunity to explore these links in the general population. Until recently measuring testosterone on a population survey has proved difficult because accurate measurement required blood samples; and because samples have to be taken at the same time of day for all respondents (due to variation in levels throughout the day).
We developed a new accurate method of measuring salivary testosterone in men and women (using LC-MS/MS) for the third British National Survey of Sexual Attitudes and Lifestyles (Natsal-3).
Methods
Having obtained consent to the sample, interviewers left a self-collection pack with the respondent. Respondents were asked to take the sample first thing in the morning and post to the laboratory the same day. Interviewers telephoned the respondent to remind them to post the sample. A token of appreciation (£5 voucher) was posted to the respondent once the sample was received.
Findings
9170 people were eligible to provide a saliva sample. 6515 of these (71%) agreed during the interview, and 4725 samples were received by the laboratory (52% of those eligible).
Conclusions
It is now possible to accurately measure salivary testosterone on a general population survey. However, as samples to be taken at the same time of day for all participants self-administered samples are needed, which may impact on response rates.
*additional co-authors: Phil MacDonald, Halina MacIntyre
Background
The Third British National Survey of Sexual Attitudes and Lifestyles (Natsal-3) will estimate population prevalence of five STIs (Chlamydia trachomatis, Neisseria gonorrhoeae, type-specific Human Papilloma Virus, HIV and Mycoplasma genitalium) in a probability sample aged 16-44y. This raises complex ethical issues, including non-return of results, testing in under-18s, consent and confidentiality.
Approach
The Natsal team undertook extensive development to design an acceptable approach to STI testing, including consultation with stakeholders, peer review and piloting. We considered the following: availability of free STI testing in Britain; impact of survey conditions and sample-type on test accuracy and timeliness; implications of testing for some STIs where the clinical and public health implications are unknown; a uniform approach is easier to explain and be understood; cost of and practical difficulties in returning results; non-clinical interviewers.
The agreed approach was for voluntary anonymised testing with no return of results, with specific consent for this, and participants given information about accessing clinical tests and sexual health. Our rationale was accepted by a research ethics committee (REC). Overall, 60% (5030/8449) of Natsal-3 participants agreed to provide samples and 98% (4924/5030) agreed to sample storage for future research.
Conclusions
The testing of STIs and decision not to return STI testing results was acceptable to Natsal-3 respondents. Our experiences may inform the ethical considerations of researchers, RECs and funders when designing population-based biological sampling.
*Additional authors: Kate Soldan, Simon Beddows, Catherine Ison, Anne Johnson, Pam Sonnenberg