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CAC in younger adults linked to substantially increased CHD risk
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The presence of coronary artery calcium among adults aged 32 to 46 years was associated with a fivefold increased risk for fatal and nonfatal CHD, according to a study with 12.5 years of follow-up published in JAMA Cardiology.
In a previous report, data from the CARDIA study showed nonoptimal levels of modifiable CV risk factors at age 25 years were linked to prevalence of CAC measured 15 years later. In the present study, that CAC prevalence was linked to elevated CHD risk.
“The finding that CAC present by ages 32 to 46 years is associated with increased risk of premature CHD and death emphasizes the need for reduction of risk factors and primordial prevention beginning in early life,” John Jeffrey Carr, MD, MSc, of the Vanderbilt University Medical Center in Nashville, Tennessee, and colleagues wrote.
The CARDIA study enrolled 5,115 participants aged 18 to 35 years between March 25, 1985, and June 7, 1986.
Investigators for the prospective, community-based study have observed the patients for 30 years, with CAC measured 15 years (n = 3,043), 20 years (n = 3,141) and 25 years (n = 3,189) after recruitment.
Researchers defined incident CHD as fatal or nonfatal MI, ACS without MI, coronary revascularization or CHD death.
Incident CVD was defined as CHD, stroke, HF and peripheral artery disease.
The researchers used clinical risk factors measured 7 years apart from age 18 to 38 years to estimate the probability of developing CAC by age 32 to 46 years.
At 15 years, 309 of the 3,043 participants (10.2%) had CAC with a geometric mean Agatston score of 21.6 (interquartile range, 17.3-26.8).
At 12.5-year follow-up, researchers documented 57 incident CHD and 108 incident CVD events.
When adjusted for demographics, risk factors and treatments, CHD events were fivefold higher in patients with any CAC vs. those with none (HR = 5; 95% CI, 2.8-8.7) and CVD events were increased threefold in those with any CAC vs. those with none (HR = 3; 95% CI, 1.9-4.7).
Compared with a CAC score of 0, the HRs for CHD were 2.6 (95% CI, 1-5.7) for those with a score of 1 to 19, 5.8 (95% CI, 2.6-12.1) for those with a score of 20 to 99 and 9.8 (95% CI, 4.5-20.5) for those with a CAC score of 100 or more, Carr and colleagues found.
According to the results, there were 22.4 deaths per 100 participants with a CAC score of 100 or more (HR = 3.7; 95% CI, 1.5-10); of the 13 deaths in participants with a CAC score of 100 or more, 10 were determined to be CHD events.
Those above the median risk for developing CAC were identified by risk factors for CVD in early adult life. Carr and colleagues wrote that if those factors were applied to screening criteria, the number of people screened for CAC could be reduced by 50% and the number needed to image to find one person with CAC could drop from 3.5 to 2.2.
“Any CAC in early adult life, even in those with very low scores, indicates significant risk of having and possibly dying of [an MI] during the next decade beyond standard risk factors and identifies an individual at particularly elevated risk for [CHD] for whom aggressive prevention is likely warranted,” the researchers wrote. – by Dave Quaile
Disclosure: The researchers report no relevant financial disclosures.
Perspective
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Robert L. Wilensky, MD
There are several important findings in the current study. No. 1, even a low CAC score, independent of the Framingham Risk Score, is associated with an increased clinical event rate in young adults. No. 2, in young adults, the presence or absence of CAC provides additional information, along with the presence of cardiac risk factors, in the determination of the risk for the development or presence of CVD. No. 3, any measurable CAC in participants 32 to 46 years of age was associated with a fivefold increase in CHD events and a threefold increase in CVD events during the 12.5 years of follow-up. No. 4, the presence of coronary calcifications, found on chest CT scans performed for other, noncardiac indications, should alert the physician to the possibility that the patient is at increased risk for the subsequent development of CAD and the increased risks associated with CAD.
If a patient has CVD risk factors at a young age, the physician should inform and educate the patient on the risk for developing CHD and assess and treat all modifiable risk factors, ie, diabetes, hypertension and hypercholesterolemia. If such cardiac risk factors are present, determination of CAC is helpful in the clinical decision-making process of whether to aggressively treat those risk factors, as well as being vigilant for the development of symptoms that may herald an untoward coronary or CV event.
If a patient has CAC as a young adult, a physician should recommend potentially aggressive management (based on CAC score) of diabetes, hypertension and hypercholesterolemia if present.
I would like to see a study designed to assess whether early preventive treatment of risk factors in patients with CAC prolongs life and/or decreases CV events. It would also help to learn more about the role of statins in decreasing CV events as well as risk of starting statins in younger patients. We also need better guidance on who should undergo CAC evaluation at an early age. Should it be based on family history of CV events.
CARDIA is a community-based, population-based study approximately balanced by sex, age, race/ethnicity and educational level, thereby extending the results to a large number of individuals.
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