Modeling the Recommended Age for CAC Testing Among At-Risk Young Adults

Quick Takes

  • Coronary artery calcium (CAC) scoring by CT is recommended for risk stratification among adults 40 years of age at borderline to intermediate risk when there is uncertainty in the initiation of primary prevention pharmacotherapy.
  • There is no evidence that delaying CV risk factor treatment would be more cost-effective for young and middle-aged persons by waiting for an age at which CAC would be more likely detected.
  • In persons most likely to have premature CAC, the time lag between CAC >0 to CAC >100, which identifies a high-risk group, is 10–15 years. Considering that earlier intervention of persons with CV risk factors may prevent progression and new soft plaque, and that effective treatments are safe and inexpensive, the clinician and patient have the option of an early treatment strategy.

Study Questions:

What is the ideal age at which a first coronary artery calcium (CAC) scan has the highest utility according to atherosclerotic cardiovascular disease (ASCVD) risk factor profile?


The study included 22,346 CAC Consortium participants aged 30-50 years who underwent noncontrast computed tomography (CT). Sex-specific equations were derived from multivariable logistic modeling to estimate the expected probability of CAC >0 according to age and the presence of ASCVD risk factors.


Average age was 43.5 years, 25% were women, and 34% had CAC >0, in whom the median CAC score was 20. Compared with individuals without risk factors, those with diabetes developed CAC 6.4 years earlier on average, whereas smoking, hypertension, dyslipidemia, and a family history of coronary heart disease were individually associated with developing CAC 3.3-4.3 years earlier. Using a testing yield of 25% for detecting CAC >0, the optimal age for a potential first scan would be at 36.8 years in men and 50.3 years in women with diabetes, and 42.3 years in men and 57.6 years in women without risk factors.


The derived risk equations among health-seeking young adults enriched in ASCVD risk factors inform the expected prevalence of CAC >0 and can be used to determine an appropriate age to initiate clinical CAC testing to identify individuals most susceptible for early/premature atherosclerosis.


A CAC = 0 in middle age and elderly provides a warranty for long periods free of ASCVD. Yet it is not necessarily helpful and may discourage treatment of risk factors in young persons who may have mild–moderate significant noncalcified plaque burden between 20–50 years for which therapy may stabilize, and delay progression and/or promote regression.

Clinical Topics: Congenital Heart Disease and Pediatric Cardiology, Diabetes and Cardiometabolic Disease, Dyslipidemia, Noninvasive Imaging, Prevention, CHD and Pediatrics and Arrhythmias, CHD and Pediatrics and Imaging, CHD and Pediatrics and Prevention, CHD and Pediatrics and Quality Improvement, Computed Tomography, Nuclear Imaging, Hypertension, Smoking

Keywords: Atherosclerosis, Coronary Disease, Coronary Vessels, Diabetes Mellitus, Dyslipidemias, Hypertension, Middle Aged, Plaque, Atherosclerotic, Primary Prevention, Risk Factors, Smoking, Tomography, Tomography, X-Ray Computed, Young Adult

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