We tend to think of heart disease as a problem that arrives sometime after 50. A new report from the FF-CHAYA study, published in Circulation: Population Health and Outcomes, suggests the process starts much earlier and can already be measured in people barely out of their teens.
Researchers examined 1,283 young adults with an average age of 22.9 years, drawn from 20 large American cities. They measured blood pressure, body composition, cholesterol, hemoglobin A1c, and kidney function, scored each person’s overall cardiovascular health, and then took ultrasound images of the carotid arteries in the neck to look for the earliest structural signs of arterial injury.
Only about 1 in 5 of these young adults had no cardiovascular-kidney-metabolic risk factors. And the arteries of those carrying more risk factors were already measurably different.
The framework: staging metabolic risk before disease appears
The American Heart Association recently introduced a construct called Cardiovascular-Kidney-Metabolic (CKM) Syndrome, built on the recognition that heart disease, kidney disease, and metabolic dysfunction are not separate problems but one interconnected process. The staging runs from 0 to 4, and this study looked at Stages 0-3.
Stage 0 means no CKM risk factors. Stage 1 means excess or dysfunctional body fat. Stage 2 means metabolic or kidney risk factors have appeared, such as elevated blood pressure, abnormal lipids, elevated blood sugar, or reduced kidney function. Stage 3 means subclinical cardiovascular disease is present, meaning damage is detectable by testing even though the person feels entirely well and has no diagnosis.
Alongside this, the researchers used the AHA’s Life’s Essential 8 score, a 0-100 measure built from eight components: diet quality, physical activity, sleep, nicotine exposure, body mass index, blood sugar, blood lipids, and blood pressure. Higher is better, with 80 or above considered high cardiovascular health and below 50 considered low.
What they found
The distribution alone is sobering. Among these 23-year-olds, 20.7% were Stage 0, 40.2% were Stage 1, 36.2% were Stage 2, and 2.8% were already Stage 3. That means roughly 79% had crossed into some stage of CKM Syndrome before their mid-twenties, and nearly 4 in 10 already had metabolic or kidney risk factors or worse.
The average body mass index in the full group was 29.0, sitting right at the edge of the obesity threshold. Average waist circumference was 82.6 cm. Notably, the Stage 0 group had an average BMI of 21.5 and an average HDL cholesterol of 61.6 mg/dL, compared with 51.4 mg/dL for the full group.
Cardiovascular health scores tracked closely with stage. The average Life’s Essential 8 score was 69.2 overall, ranging from 77.6 in Stage 0 down to 64.4 in Stage 3. Compared with Stage 0, scores were 7.6 points lower in Stage 1, 13.9 points lower in Stage 2, and 13.2 points lower in Stage 3. For context, the authors note that even a 10-point difference in this score has been linked to significantly lower cardiovascular risk in prior research.
Then came the ultrasound findings, where the study earns its attention.
Carotid intima-media thickness is a measurement of the innermost layers of the artery wall. It thickens quietly as atherosclerosis begins, long before any blockage, symptom, or event. In this group, that thickness increased steadily with each advancing CKM stage. Compared with Stage 0, mean-maximum thickness was 0.014 mm greater in Stage 1, 0.020 mm greater in Stage 2, and 0.100 mm greater in Stage 3. A companion measure of arterial wall texture, the gray scale median, also moved in the unfavorable direction across stages, and markers of arterial stiffness also differed.
Why fractions of a millimeter matter
A tenth of a millimeter sounds like nothing. It is not.
The authors point out that in older adults, differences of this same small magnitude, 0.10 mm or less, have been associated with significantly higher rates of heart attack and stroke. They also observe something more concerning: the artery wall measurements seen in this cohort would be considered advanced for people this young. In other words, these are not simply differences between young people. They may represent arteries that are aging ahead of schedule.
That is the real message. The difference between Stage 0 and Stage 2 at age 23 is not a difference in how someone feels. Nobody in this study had symptoms. It is a difference in trajectory, and trajectories compound over decades.
The most interesting finding was one that showed no difference
Here is a detail that deserves more attention than it will probably get. When the researchers looked only at the four behavior components of the score, meaning diet, physical activity, sleep, and nicotine exposure, there was no significant difference across CKM stages. Diet scores averaged 39.9 and physical activity scores averaged 42.5, both in the low range, and both were low in every group, including Stage 0.
So the young adults with pristine arteries were not eating better or exercising more than everyone else. Their measured biology was simply better so far.
The authors offer a reasonable interpretation: self-reported questionnaires are blunt instruments for capturing what people actually eat and how much they actually move, and behaviors sit further upstream in the causal chain, meaning they take longer to show up as measurable arterial change than blood pressure or lipids do. Poor habits at 23 have not yet fully cashed out in the artery wall.
That cuts both ways. It means the Stage 0 group has no grounds for complacency, since their behavior scores were low too and their advantage may be temporary. And it means the Stage 1 and 2 groups still have runway.
What this study cannot tell you
Honesty requires naming the boundaries of the evidence.
This was a cross-sectional study, a single snapshot in time. It cannot establish that CKM stage caused the arterial changes, only that the two travel together. Many outcomes were tested simultaneously, which raises the odds that some findings are chance.
The cohort is also distinctive. It was drawn from a study that deliberately oversampled families facing economic hardship, and it does not represent all young Americans. Roughly half of participants had experienced parental incarceration, and about 76% had household income below 300% of the federal poverty level at the time of their birth. These figures reflect real and important context about who was studied, and they mean the prevalence numbers here run higher than in nationally representative samples of US adolescents.
Finally, the overlap between CKM staging and the cardiovascular health score is partly definitional, since both are built from blood pressure, lipids, glucose, and body mass index. The carotid ultrasound findings, however, are independent measurements, and they carry the weight.
The practical takeaway
Three things follow from this study for anyone in their twenties, thirties, or forties, or for any parent of a young adult.
First, absence of symptoms is not evidence of health. The Stage 3 participants in this study, with detectable subclinical disease, felt fine. Waiting for symptoms means waiting for damage that has already accumulated for decades.
Second, ordinary screening is often too shallow and too late. The variables that separated these groups, adiposity and waist measurement, lipid patterns including HDL, blood pressure, glycemia, and kidney filtration, are all measurable now, cheaply, in anyone. So is carotid intima-media thickness, which requires nothing more invasive than an ultrasound probe on the neck.
Third, and most encouraging, every single one of the eight components in this scoring system is modifiable. Diet quality, activity, sleep, nicotine exposure, body composition, blood sugar, lipids, and blood pressure all respond to intervention. Two of the eight scored poorly across every group in this study, which is not a verdict so much as an open door.
The human body is designed with a remarkable capacity for repair, but that capacity works best early, while the damage is still measured in hundredths of a millimeter rather than in stents and rehabilitation. Stewardship of the body means looking before anything is obvious.
If you are a young adult, or you have one in your family, this study argues for getting a baseline: a comprehensive metabolic panel, a proper lipid assessment, blood pressure done correctly, and a conversation about what those numbers mean at your age rather than at 60.
