A 10-year study involving more than 6,000 adults found that coronary calcium scans, which are used to assess heart disease risk, may not significantly improve standard risk estimates for most people. However, for individuals with borderline or intermediate risk of heart disease, these scans could offer a more accurate assessment of their actual risk. Coronary artery calcium scans are a type of CT scan that measures calcium buildup in the arteries supplying blood to the heart. This test is becoming more common as a tool to predict future heart disease risk. The study, conducted by researchers at Northwestern Medicine, compared the effectiveness of coronary artery calcium scans with PREVENT, a widely used risk calculator developed by the American Heart Association. PREVENT estimates a person's likelihood of developing cardiovascular disease over the next 10 or 30 years based on factors like blood pressure, cholesterol levels, age, and sex. In contrast, a calcium scan directly measures calcium-containing plaque in the coronary arteries. The resulting calcium score indicates the amount of plaque present, with higher scores suggesting greater future risk. The findings suggest that calcium scans are most beneficial for people whose initial risk, as estimated by PREVENT, falls in the borderline or intermediate range—those with a 3% to 9% chance of heart disease in 10 years. For these individuals, the scan can provide a clearer picture of their actual risk, helping to guide treatment decisions. However, the study also highlights potential drawbacks of using calcium scans for people at low or high risk. For low-risk individuals, the scans may expose them to unnecessary radiation and costs without clear benefits. For high-risk individuals, scans may not change treatment plans since they are typically advised to start taking statins regardless of their calcium scores. The researchers examined data from over 6,000 adults aged 45 to 79 participating in the Multi-Ethnic Study of Atherosclerosis. Each participant received both a calcium scan and a PREVENT risk assessment. Over the next decade, 6% of participants experienced a heart attack or stroke. When comparing predictions based on PREVENT alone with those that included calcium scores, the improvement was modest overall. However, for those in the borderline or intermediate risk group, the addition of calcium scores led to a more meaningful improvement in predicting future cardiovascular events. The study underscores the importance of accurately identifying individuals at risk of heart disease to guide preventive treatments like statins. About 10% of U.S. adults aged 30 to 79 have cardiovascular disease, which remains the leading cause of death in the country. The findings suggest that the PREVENT calculator is already effective at predicting risk without the need for calcium scans for most people. However, further research is needed to determine how calcium scores might improve risk estimates in specific groups, such as South Asian and Filipino adults, and in younger populations. This research helps clarify how best to use available tools to guide treatment decisions and improve outcomes for those most likely to benefit from preventive care.