News · Longevity & Aging
Coronary calcium scan: who it helps, in 10 years of data on 6,098 US adults
New US cholesterol guidelines recommend heart calcium scans for people at middle-of-the-road risk. A decade of follow-up shows the scan adds little overall, but sorts borderline-risk people usefully.
- An observational study of 6,098 US adults aged 45 to 79 without heart disease, followed for 10 years.
- Researchers checked how much a coronary calcium score added to the newest US heart risk calculator.
- Across everyone, adding the scan improved predictions only modestly.
- In borderline-risk people, heart events ranged from 1.9% with a zero score to 14.3% with a score of 300 or more.
- The results back scanning selectively, for people at borderline to intermediate risk, rather than everyone.
Should a healthy-feeling person in their fifties get a scan of the heart’s arteries? New US cholesterol guidelines now say yes for some: those whose calculated risk sits in the middle, where the decision about a statin is hardest.
A study in JAMA tested what that scan actually adds. Across 6,098 adults followed for a decade, the calcium score improved risk predictions only modestly overall, but for people at borderline risk it separated those with very low odds of a heart attack from those with high odds.
What a calcium score measures
MedlinePlus explains that coronary artery disease develops slowly over time when plaque builds up inside your coronary arteries, and that plaque is a waxy, sticky substance made of fat, cholesterol, calcium, and other materials. The calcium is what a CT scan can see, and it is turned into a score.
Doctors already estimate heart risk with calculators. The authors note that the 2026 American College of Cardiology/American Heart Association guideline newly recommends selective use of coronary artery calcium (CAC) scoring for people with a 10-year risk of 3% to under 10% on the new PREVENT calculator. Previously, how much the scan adds to that particular calculator was not known.
How the calcium scan study worked
The data came from the Multi-Ethnic Study of Atherosclerosis, which enrolled adults aged 45 to 79 at six US sites and scanned their hearts at the start. A total of 6098 participants were included, averaging 61 years old; about half had some calcium.
The researchers calculated each person’s 10-year risk with the PREVENT equations, then again with the calcium score added, and compared both against what actually happened over the following decade: 366 people, or 6%, had a heart attack, stroke or related event.
What the scan added
Overall, not much. The calculator alone was already reasonably good at ranking who would have an event, and adding the calcium score nudged that up only slightly. The authors write that adding CAC across all risk groups overall only modestly improved predictions, and in some groups did not change them.
The picture was sharper at the borderline. Among people whose calculated risk was 3% to 5%, events occurred in 1.9% of those with a score of zero, but in 7.4% with scores of 100 to 299 and 14.3% with scores of 300 or more. Scores reclassified people in a way that matched their later outcomes.
Why the borderline group is where scans help
For someone at borderline risk, the question is whether to start a statin. A zero score points toward holding off; a high score points toward treatment. That is exactly the decision the guideline has in mind, and this study supports using the scan there rather than for everyone.
The authors conclude that the reclassification results support selective use of CAC in those with borderline to intermediate risk. For people already clearly at low or high risk, the scan is unlikely to change what they should do.
What a single calcium scan study cannot settle
This measures prediction, not benefit. It does not show that people who have a scan, and act on it, have fewer heart attacks than people who do not; that would need a trial.
Participants were scanned years ago and treated according to the standards of the time, and the cohort, while ethnically mixed, may not match everyone. The scan also carries costs: a small radiation dose, incidental findings that prompt more tests, and bills that insurers often do not cover.
What this changes about getting a calcium scan
If your doctor has put your 10-year risk in the borderline or intermediate range and you are undecided about a statin, a calcium score is a reasonable tie-breaker to ask about. A score of zero is reassuring in the short to medium term; a high score is a signal to take cholesterol, blood pressure and lifestyle seriously.
For people at low risk, the scan is unlikely to add much. For people at high risk, treatment is usually recommended regardless of what it shows.
People also ask
What did the study find?
Over 10 years, 366 participants (6%) had a heart attack, stroke or related event. The PREVENT equations alone had a C statistic of 0.73; adding calcium scores raised it by 0.02, with a net reclassification improvement of 0.095. Among people at borderline risk, events occurred in 1.9% with a score of 0, 3.9% with 1 to 99, 7.4% with 100 to 299 and 14.3% with 300 or more.
What is a coronary calcium scan?
A quick CT scan of the chest that measures calcium in the walls of the heart's arteries. Calcium is a marker of built-up plaque, and the result is given as a score, where 0 means none was seen.
What is the PREVENT calculator?
A risk equation from the American Heart Association that estimates a person's chance of a heart attack or stroke over 10 years from age, blood pressure, cholesterol, diabetes, smoking and kidney function.
Who might benefit from a scan?
The new US guideline suggests considering one when estimated 10-year risk is between 3% and 10%. This study supports its use mainly at the borderline to intermediate levels, where the result can shift a decision about statins.
Are there downsides?
The scan involves a small dose of radiation, can find unrelated incidental findings that lead to more tests, and is often not covered by insurance. A high score should lead to a conversation, not panic.
Should I ask for one?
If you are unsure whether to start a cholesterol-lowering drug, ask your doctor whether a calcium score would help the decision. This is general information rather than medical advice.