Silent Killers in the Arteries: Groundbreaking International Study Reveals Widespread Hidden Atherosclerosis in Apparently Healthy Young Adults
Cardiovascular disease remains the leading cause of mortality worldwide, claiming nearly 20 million lives annually. For decades, the medical consensus held that the primary driver of these fatal events—atherosclerosis, the insidious accumulation of plaque inside arterial walls—developed slowly over a lifetime, usually remaining clinically silent until middle or older age when it triggered a heart attack, stroke, or sudden cardiac death. However, a massive new international study has shattered this long-held medical assumption, revealing that the roots of cardiovascular disease take hold much earlier in life than previously understood and are profoundly more widespread among healthy, asymptomatic young adults.
The findings, emanating from the first phase of the ambitious multi-year Research on Atherosclerosis and cardiovascular prevention (REACT) project, were unveiled during a prestigious Hot Line session at the European Society of Cardiology (ESC) Congress and published simultaneously in The New England Journal of Medicine. Analyzing a cohort of more than 16,000 seemingly healthy individuals across Denmark and Spain, researchers discovered that over 57% of participants harbored hidden atherosclerotic plaques. Most alarmingly, the data showed that even individuals in their late teens and twenties are already developing arterial disease, signaling an urgent need to rethink how global healthcare systems evaluate, monitor, and prevent cardiovascular complications.
A Revolutionary Paradigm Shift: From Risk Estimation to Direct Detection
Led by a consortium of prominent European cardiologists—including Professor Henning Bundgaard, Professor of Cardiology at Rigshospitalet in Copenhagen, Denmark, and Dr. Borja Ibáñez, Scientific Director of the Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), cardiologist at Hospital Universitario Fundación Jiménez Díaz, and group leader at CIBERCV—the REACT initiative challenges the foundational framework of modern preventive cardiology.
Historically, primary cardiovascular prevention has relied on an indirect probabilistic model. Physicians calculate a patient’s future risk of experiencing a cardiovascular event over a 10-year span by evaluating traditional risk markers, such as systemic blood pressure, serum cholesterol levels, smoking habits, and age. While this risk-estimation approach has guided medical practice for generations, it has a glaring limitation: it estimates probabilities rather than diagnosing the actual presence of pathology. Consequently, millions of patients categorized as "low risk" based on standard scores experience unexpected cardiovascular events because the underlying disease was silently progressing undetected.
The REACT study seeks to upend this model by substituting risk estimation with direct, non-invasive imaging. Instead of guessing who might develop arterial plaque based on statistics, the research team advocates for screening individuals directly to identify whether the disease is already physically present in the body. Under this proposed precision medicine paradigm, medical interventions, lifestyle modifications, and pharmacological treatments would be tailored to the patient’s actual arterial health status rather than an abstract mathematical score.
Unprecedented Scope and Methodology of Phase 1 (REACT-DETECT)
Funded generously by up to €23 million in support from the Novo Nordisk Foundation for its initial phase, REACT represents one of the most comprehensive investigations into the natural history of silent atherosclerosis ever undertaken. Phase 1 of the project, formally designated as REACT-DETECT, commenced in 2024 and successfully enrolled 16,808 participants aged 18 to 70 across Denmark and Spain. Crucially, none of the participants possessed a known history of cardiovascular disease or displayed overt clinical symptoms.
To construct a definitive atlas of vascular health, researchers subjected every participant to a rigorous battery of advanced diagnostic examinations. The core protocol utilized sophisticated medical imaging to inspect three major vascular territories for the presence of plaque: the carotid arteries supplying the brain via the neck, the femoral arteries supplying the lower limbs, and the coronary arteries feeding the heart muscle itself.
Beyond imaging, the investigative framework was extraordinarily thorough. The project team gathered exhaustive metadata on cardiovascular risk factors, collected precise blood biomarkers, extracted biological samples for downstream omics analyses, and performed detailed examinations of retinal images. The resulting repository stands as one of the most granular multi-modal databases on human atherosclerosis assembled to date, offering researchers a rare window into the systemic nature of the condition.
Key Findings: The Surprising Prevalence of Early-Onset Plaque
The results of Phase 1 paint a sobering yet illuminating picture of how atherosclerosis evolves across the adult lifespan. Overall, atherosclerotic plaques were detected in 57.1% of the entire study cohort. However, the breakdown of prevalence across different age brackets yielded the most disruptive insights.
Among the youngest cohort—adults aged 18 to 29—approximately 1 in 13 individuals (roughly 7.7%) already exhibited verifiable signs of atherosclerotic plaque in at least one major artery. While this percentage is lower than older groups, its mere existence in people who feel entirely healthy and vigorous underscores that vascular degeneration can begin almost as soon as early adulthood commences.
Following this baseline, the prevalence of the disease climbed steeply and predictably with advancing age. By the time individuals reached middle age, plaque accumulation was the norm rather than the exception. Among participants aged 60 to 70, approximately 9 in 10 individuals (around 90%) displayed evidence of atherosclerosis.
These revelations build directly upon foundational insights from earlier landmark research, such as the PESA-CNIC-Santander study directed by Dr. Valentin Fuster, General Director of CNIC and a key collaborator in the REACT initiative. While PESA demonstrated that middle-aged adults frequently harbor undiagnosed plaque linked to lifestyle factors, REACT pushes the timeline back by decades, capturing the precise developmental window in which the disease first emerges.
The Diagnostic Potential of Portable Ultrasound
One of the most clinically actionable discoveries to emerge from the REACT data concerns the anatomical distribution of plaque across different vascular beds. The imaging analyses revealed a striking pattern of systemic overlap: the vast majority of participants who presented with atherosclerotic plaques in their high-risk coronary arteries also exhibited detectable plaque in their carotid or femoral arteries.
This high degree of correlation carries immense implications for the future economics and logistics of global health screening. Examining coronary arteries directly requires advanced imaging technologies, such as computed tomography (CT) scans, which involve radiation exposure, higher costs, and limited accessibility in primary care settings. In contrast, evaluating the carotid and femoral arteries can be accomplished swiftly, safely, and non-invasively using standard ultrasound equipment.
Dr. Ibáñez emphasized the transformative potential of this anatomical overlap for everyday clinical practice. He noted that in the newly proposed paradigm, portable ultrasound devices—simple enough to be operated by a wide range of healthcare professionals—could become the standard instrument for screening atherosclerosis from early adulthood onward. By identifying peripheral plaque easily in a doctor’s office, clinicians could infer the likelihood of hidden coronary disease without resorting to expensive or complex diagnostic procedures for every patient.
Divergent Pathways: Sex Differences in Arterial Aging
The REACT study also shed light on the notable physiological differences in how atherosclerosis manifests and progresses in men compared to women. By tracking the condition across thousands of individuals over a wide age span, researchers uncovered distinct trajectories tied to sex.
In male participants, the accumulation of arterial plaque began accelerating at notably younger ages. Overall, the chronological pattern of atherosclerosis progression in men appeared approximately five to ten years ahead of the timeline observed in women.
Conversely, female participants exhibited a different temporal curve, characterized by a sharp, dramatic rise in plaque prevalence between the ages of 40 and 60. This concentrated window of rapid vascular aging broadly coincides with the menopausal transition, suggesting that hormonal shifts play a critical role in accelerating arterial disease in women.
These distinct epidemiological trajectories underscore the absolute necessity for future preventive strategies to account for both sex and specific life stages, moving away from a generalized "one-size-fits-all" approach to cardiovascular medicine.
Exposing the Blind Spots of Traditional Risk Scores
Perhaps the most consequential realization stemming from the REACT data is the profound inadequacy of traditional risk assessment models when evaluated against direct imaging. When the research team applied standard international risk stratification scores—such as SCORE2—to the study population, they discovered that these conventional algorithms identified only a tiny fraction of the individuals who actually possessed silent atherosclerosis.
This systemic blind spot means that millions of people walking around with low or moderate calculated risk scores are lulled into a false sense of security, unaware that plaque is quietly developing within their arterial walls. Professor Bundgaard highlighted this dichotomy, noting that while traditional methods tell us what a patient’s statistical probability of disease might be, direct imaging tells us the empirical truth of whether the disease is already active.
"For decades, we have estimated cardiovascular risk using factors such as age, blood pressure, and cholesterol," Dr. Ibáñez remarked. "This study shows that we can now go one step further and detect the disease directly before it causes a heart attack or stroke. If we identify atherosclerosis in its earliest stages, we will be able to intervene sooner, tailor treatment more effectively, and reduce the burden of cardiovascular disease."
Chronology and Future Horizons: The Path to Phase 2
The completion of Phase 1 marks merely the opening salvo of a much larger, eight-year scientific roadmap. Following the successful execution of REACT-DETECT (2024–2026), the initiative is poised to enter its second major phase, subject to continued grant funding.
Planned to run from 2027 through 2032, Phase 2 (REACT-PROTECT) will transition from observational data collection to active clinical intervention. The research team intends to launch a massive, international randomized clinical trial designed to test a fundamental clinical question: Does an imaging-guided preventive strategy actively slow or reverse the systemic progression of atherosclerosis better than standard care? Furthermore, the trial aims to determine whether this proactive approach can definitively reduce the incidence of clinical heart attacks, strokes, and cardiovascular-related deaths.
Dr. Fuster expressed optimism regarding the ultimate therapeutic potential of this early-intervention model, noting that for years, researchers have hypothesized that catching atherosclerosis in its infancy might not only halt its progression but potentially render the disease curable. REACT, he noted, is structured to provide the definitive answer to that hypothesis.
Expanding the Global Footprint
Recognizing that cardiovascular disease manifests differently across diverse genetic, environmental, and socioeconomic landscapes, the leadership team is actively expanding the reach of the REACT project beyond Europe. Collaborative networks have already been established with medical institutions in India, Singapore, Tanzania, and Mexico.
By validating the findings of the European cohorts within these diverse global populations, the consortium hopes to construct a universally applicable framework for early cardiovascular detection. This international expansion ensures that the insights gained from REACT can be translated into actionable public health policies worldwide, offering a blueprint to mitigate the leading cause of death on a global scale.
As the medical community digests the profound implications of the REACT-DETECT data, the paradigm of cardiology appears poised for a historic transformation. By replacing abstract risk estimations with direct, early visualization of arterial health, modern medicine may soon possess the tools necessary to intercept cardiovascular disease decades before it strikes, fundamentally altering the trajectory of human longevity.
