Collecting biomarkers in social surveys: Dried Blood Spots in SHARE
Health is a major concern for ageing societies. More and more social surveys are therefore implementing the collection of biomarkers, objective measures of biological and physical functions which help to overcome the inherent biases associated with self-reported health measures and improve the precision of health measurement.
Examples of biomarkers include performance measures such as grip strength and walking speed, and biological markers in blood such as blood sugar, cytokines and cholesterol. However, despite the increased analytic potential provided by biomarkers, the collection of this new form of data as part of a social survey presents challenges.
As part of the SERISS project, researchers from SHARE ERIC are drawing on their experiences of implementing a Dried Blood Spot (DBS) collection in Wave 6 of the Survey of Health Ageing and Retirement in Europe (SHARE) to explore legal, ethical and practical issues associated with the collection and storage of the samples cross-nationally and to develop strategies for the inclusion of biological markers in population-based social surveys.
Ethics and legal requirements
The first output from the work on DBS taking place under SERISS is a report summarising the legal, ethical and associated administrative requirements that have to be taken into account when collecting DBS in different European countries. These requirements can vary considerably from one country to another.
Some of the key lessons learned from the implementation of the DBS collection in SHARE include:
- According to legal and occupational requirements in some countries (including Austria, Poland and the Czech Republic) capillary blood can only be taken by medical personnel, i.e. doctors or nurses. The implementation of the DBS collection on SHARE assumes that the samples are collected by trained interviewers as part of the main face to face interview. Employing medical personnel is unlikely to be either practically or financially feasible in the context of a large scale cross-national survey, meaning that DBS cannot be collected in all countries.
- A collection of DBS requires researchers to consult and gain approval from different administrative authorities which can be time consuming. In quite a few countries the national data protection authority has to be consulted. In addition, researchers need to liaise with national or local research ethics committees who, depending on whether they have a social sciences or clinical focus, may have different levels of familiarity with the collection of biomarker data in the context of population-based social surveys. In this regard, the organisation of the ethics committee systems differs a lot between the countries.
- Even though requirements for obtaining consent of participants have been observed to be similar across countries on a general level, requirements differ when it comes to the implementation of consent procedures.
The report includes summary tables of the specific legal and ethics requirements for a collection of DBS in 19 European countries and Israel. The tables provide a useful resource for researchers who may be interested in collecting biomarkers as part of other social surveys.
Read SERISS Deliverable D6.10 (PDF) to find out more.
The importance of consent
Collecting biomarkers requires respondents’ informed consent and adds new tasks to the interviewer as they are the ones asking for consent and conducting the measures. Systematic differences between consenting and refusing respondents will lead to consent bias. For example, previous waves of data collection in SHARE show remarkable interviewer effects in respondents’ willingness to consent.
The next stage of work on DBS under SERISS will be to explore the experiences of gaining consent for the DBS collection in SHARE Wave 6 by exploiting information from interviewer questionnaires. These questionnaires collect markers of the interviewers’ own attitudes vis-à-vis health measurement, risk behaviour, and modern technology. We will correlate these markers with actual consent rates of respondents and conditional on the prevailing national (sometimes local) legal and ethical provisions and guidelines. Results will be available in Summer 2017.
The SHARE DBS data
Since the collection of the samples, preparations for the analysis of the SHARE Wave 6 DBS being stored at the SHARE Biobank located in Odense, Denmark were initiated. Approximately 25,000 DBS samples will be analysed for several markers, including glycated haemoglobin (hbA1c), an indicator of diabetes, blood fats, like cholesterol and triglycerides, and C-reactive protein and other cytokines, markers of inflammation and associated with conditions including cardiovascular disease.
Analyses will be conducted in experienced laboratories in Copenhagen, DK, and Seattle, USA. The results, in combination with SHARE survey data, are expected to provide novel insights into the association between chronic health conditions common in old age and environmental risk factors under different socio-economic conditions. First findings as well as the DBS data will be made available via the SHARE Research Data Center (see SHARE website) once the analyses results are available.
(Author: Daniel Schmidutz, SHARE ERIC)