Distribution of CAC by Age-Sex-Race Among Patients Aged 30-45 Years

Quick Takes

  • Among the convincing support for CAC has been the utility of CAC = 0 and that CAC score provides better discrimination than age for incident ASCVD over long-term follow-up.
  • These findings are not applicable in young high-risk persons for whom age is not a good predictor of soft plaque for which treatment of lipids reduces progression and often regression.
  • An interactive webpage allows one to enter an age, sex, race, and CAC score to obtain the corresponding estimated percentile. I would be concerned that a CAC = 0 would suggest to the patient and provider that the risk factors do not need to be treated.

Study Questions:

Use of the coronary artery calcium score (CAC) to assist in risk stratification of asymptomatic men and women is effective but limited to ages 45-84 years. What is the probability of CAC >0, and what are the age-sex-race percentiles for US adults aged 30-45 years?

Methods:

The authors harmonized three datasets—CARDIA (Coronary Artery Risk Development in Young Adults), the CAC Consortium (multicenter cohort physician referred for risk stratification), and the WRC (Walter Reed Cohort; armed forces)—to study CAC in 19,725 asymptomatic Black and White individuals aged 30-45 years without known atherosclerotic cardiovascular disease (ASCVD). After weighting each cohort equally, the probability of CAC >0 and age-sex-race percentiles of CAC distributions were estimated using nonparametric techniques.

Results:

Mean age was 41 (3.3) years, 27% were women, 17% were Black, and 45% were in the WRC. CV risk factors included hyperlipidemia in 41%, hypertension in 17%, smokers 10%, and diabetes 3%. The prevalence of CAC >0 was 26% among White males, 16% among Black males, 10% among White females, and 7% among Black females. CAC >0 automatically placed all females at the >90th percentile. In White males aged 36 years, 15% had a CAC >0. An observed CAC of 8 is at the 91st percentile for individuals of the same age, sex, and race who are free of clinical ASCVD.

Conclusions:

In a large cohort of US adults aged 30-45 years without symptomatic ASCVD, the probability of CAC >0 varied by age, sex, and race. Estimated percentiles may help interpretation of CAC scores among young adults relative to their age-sex-race matched peers and can henceforth be included in CAC score reporting.

Perspective:

The CAC score has become an important tool for helping both the patient and physician decision regarding treatment and intensity. Among the convincing data has been the utility of CAC = 0 and that CAC score provides better discrimination than age for incident ASCVD over long-term follow-up. The three study cohorts were convenient but very much unrelated, and despite the ‘equal weighting to one third each’ may have introduced bias and thus not be readily generalizable; in particular, the 40% prevalence of hyperlipidemia, which is much higher than the US population of 30-45 years. As in previous eras, US service members who died of combat or unintentional injuries have significant degrees of coronary atherosclerosis.

Comparing coronary atherosclerosis prevalence among those with no CV risk factors (11%), there was a significantly greater prevalence of those with dyslipidemia (50%), hypertension (43.6%), obesity (22%), and smoking (14%). Of the risk factors, each was associated with a significant age-adjusted prevalence ratio, except for smoking (Webber BJ, et al., JAMA 2012;308:2577-83). A recent review concluded that identifying high-risk features that predict early-onset ASCVD among young adults (ages 20-39 years) can assist providers and their patients in modifying ASCVD risk factors earlier (Stone NJ, et al., J Am Coll Cardiol 2022;79:819-36).

Clinical Topics: Cardiovascular Care Team, Congenital Heart Disease and Pediatric Cardiology, Diabetes and Cardiometabolic Disease, Dyslipidemia, Noninvasive Imaging, Prevention, Atherosclerotic Disease (CAD/PAD), 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

Keywords: Atherosclerosis, Coronary Artery Disease, Diabetes Mellitus, Dyslipidemias, Hyperlipidemias, Hypertension, Middle Aged, Obesity, Plaque, Atherosclerotic, Primary Prevention, Risk Assessment, Risk Factors, Smokers, Tomography, X-Ray Computed, Vascular Calcification, Young Adult


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