Accessible Health Data in Ireland: Learnings from The Irish Longitudinal Study on Ageing (TILDA)

The Irish Longitudinal Study on Ageing (TILDA) is a large-scale study of adults aged 50+ in Ireland. Since the first wave in 2008–2010, which involved 8,504 participants, six waves of data have been collected biennially. Each wave gathers detailed information on participants’ health, social, and economic circumstances through interviews and questionnaires. At alternating waves, participants also undergo a comprehensive health assessment by a healthcare professional.

TILDA is now a major data resource with 10,965 participants and over two billion data points. Data collected includes self-reported and objective measures of cardiovascular, bone, oral, and cognitive health, as well as vision, balance, gait, physical function, and body composition. A subset of participants also provided accelerometry data, MRI scans, and biological samples (blood, saliva, hair, and faeces) for biomarker and epigenetic analysis.

Where consent is given, TILDA links participant data to administrative databases, such as the Primary Care Reimbursement Scheme, General Registry Office death records, spatial data systems, and GP electronic records.

TILDA promotes data access for research and public health by making pseudonymised datasets available via the Irish Social Science Data Archive (UCD). These undergo strict anonymisation, including top/bottom coding, grouping, and removal of sensitive variables. More detailed datasets can be accessed in trusted research environments (TREs). Historically, this was done through a secure hotdesk system in the TILDA offices, where researchers could analyse data on restricted computers. Due to increased demand-initially driven by the COVID-19 pandemic-TILDA began exploring remote access options.

Managing access to sensitive health data while complying with GDPR and Irish Health Research Regulations (HRR) is complex. TILDA initially sought to establish a secure remote access environment within Trinity College Dublin. However, it became clear this was unfeasible for this to be established for an individual study. No national infrastructure was available at the time.

As a solution, TILDA partnered with the Secure e-Research Platform (SeRP UK) at Swansea University. This platform already hosted multiple health datasets and offered tailored solutions, including full oversight and data governance, sophisticated security, and options for high performance computing. Transferring data to the UK required extensive legal and regulatory work—Data Protection Impact Assessments, evaluation of the UK’s adequacy status post-Brexit, HRCDC amendments, and detailed contracts.

To our knowledge, TILDA is the first Irish study to establish its own TRE of this scale, managed by the research study itself. The process, spanning nearly five years, was resource-intensive and administratively burdensome. While this approach may not be feasible for smaller studies, it aligns with upcoming European Health Data Space regulations and FAIR principles. TILDA’s experience highlights the need for national infrastructure to support secure, accessible health data use in Ireland. The learnings from TILDA of navigating this process may help identify where processes need to be streamlined and how infrastructure should be established, and the day to day requirements of managing systems of this nature.