Spain's 196,000-person heart disease study aims to revolutionize precision medicine

Researchers in Spain have assembled one of the most ambitious cardiovascular studies ever attempted in Southern Europe, pulling together data from nearly 200,000 people across 35 separate population cohorts. The CORDELIA study—its full name a mouthful of scientific acronyms that translates to Collaborative cOhorts Reassembled Data to study mEchanisms and Longterm Incidence of chronic diseAses—represents an attempt to answer a question that has long puzzled medicine: why does heart disease risk look so different depending on where you live?

The dataset contains 196,632 participants, averaging 52 years old, with 54 percent women and 96 percent born in Spain. About one in five hold a university degree. Half have never smoked, though a quarter report current smoking. What makes this cohort scientifically valuable is not just its size but what researchers have collected alongside basic demographics: DNA samples from 60 percent of participants, blood and plasma samples from 50 percent, and clinical follow-up data spanning anywhere from 5 to 30 years depending on which of the 35 original cohorts a person belonged to. When someone in the study experienced a heart attack, stroke, or other cardiovascular event, researchers documented it using standardized medical codes and cross-referenced it against Spain's national mortality registry and hospital discharge records.

The motivation for CORDELIA stems from a stubborn gap in medical science. Atherosclerotic cardiovascular disease—the buildup of cholesterol and fatty substances inside artery walls that eventually chokes off blood flow—kills more people globally than almost any other condition. Modern medicine has made real progress reducing deaths from heart disease, but an aging world means the absolute number of cases keeps climbing. Decades of research have identified genetic, environmental, and socioeconomic factors that drive risk. The problem is that these risk factors don't behave the same everywhere. A variable that powerfully predicts heart disease in one region may barely matter in another. Yet when researchers build predictive models for cardiovascular risk, they typically rely on data from Northern European and North American populations. Southern Europe, despite its size and distinct genetic ancestry, remains severely understudied. Only a handful of genome-wide association studies—the statistical method that scans millions of genetic variants to find which ones correlate with disease—have included meaningful numbers of Southern Europeans. This absence matters because a risk prediction tool built on Scandinavian genetics may not work well for Spanish patients.

CORDELIA aims to fill that gap by conducting what researchers describe as the most extensive cardiovascular-focused genome-wide association study yet performed in Southern Europe. The 35 cohorts that feed into it were assembled over decades using different recruitment methods—some enrolled people from the general population, others from hospitals, still others from workplaces—and they collected data using varying definitions and measurement approaches. Harmonizing this messy real-world data required developing standardized algorithms for conditions like hypertension and diabetes, and standardizing genotyping across cohorts using a common platform called the Axiom Spain Biobank Array-2. The researchers acknowledge the limitations: not all variables were measured the same way, some data came from self-report rather than clinical examination, and biological samples weren't available for everyone. But they have applied statistical methods designed to handle these inconsistencies.

Once complete, CORDELIA will generate polygenic risk scores—mathematical summaries of a person's genetic predisposition to heart disease—that can predict who among Spanish and Southern European populations faces the highest 10-year risk of a cardiovascular event. The study also plans to identify subgroups of people who would benefit most from specific medications or lifestyle changes, with particular attention to sex-specific differences in how heart disease develops and presents. These are the building blocks of precision medicine: moving beyond one-size-fits-all prevention strategies toward interventions tailored to individual genetic and clinical profiles.

This is the first joint publication from the newly harmonized CORDELIA dataset, though individual cohorts that now feed into it have contributed to published research for years. The study's comprehensive data collection—clinical measurements, genetic samples, lifestyle questionnaires, decades of follow-up—also opens doors for research beyond cardiovascular disease, including work on COVID-19, cancer, and sleep disorders. Researchers emphasize that CORDELIA exemplifies how large-scale collaborative research can advance precision medicine by integrating clinical, environmental, genetic, and socioeconomic information. But they also caution that the cohort may not fully represent the broader Spanish or Southern European population, and the power to detect associations with rare genetic variants remains limited. These are the constraints researchers will work within as they begin mining the data—constraints that matter when translating findings into clinical practice.