Data Resource Profile: Linking electronic health and social records to study and lower health inequalities in cardiovascular diseases (BIG-HEART)

The BIG-HEART cohort was established to study and reduce health inequalities in cardiovascular disease by linking rich, multidimensional electronic health and social data across Estonia. The dataset includes all individuals aged 36 and above residing in Estonia in 2012 (N= 770,323). Its full population coverage minimises sampling and healthy volunteer bias. Existing funding and permits will support annual health outcome follow-up through at least 2026, with possible future extensions. The dataset integrates all routinely collected individual-level primary and secondary care health data (including in- and outpatient visits, diagnoses, prescriptions issued and filled), mortality data, and extensive social data (e.g. ethnicity, education, marital status, social benefits, unemployment history, land and business ownership) from eight national registries. This enables exploration of novel social epidemiology dimensions--such as unbiased wealth measures, medication adherence, and care quality--and supports development of equity-enhancing clinical risk prediction algorithms and large language models. Health and social data are linked using pseudonymised identifiers derived from national personal identification numbers, ensuring accuracy and privacy. The data are stored in the OMOP common data model, facilitating international collaboration. Collaboration inquiries are welcome and can be directed to the BIG-HEART team at taavi.tillmann@ut.ee.