Risk Factors for Incident Coronary Artery Calcium in Younger (Age 32 to 45 Years) Versus Intermediate (46 to 64 Years) Versus Older (65 to 84 Years) Persons

The prognostic value of traditional atherosclerotic cardiovascular disease (ASCVD) risk factors may decrease with age. We sought to determine whether the association between traditional ASCVD risk factors and incident coronary artery calcium (CAC) differs for younger versus older persons. We included 5,108 participants with baseline CAC = 0. Repeat CAC scoring occurred over 3 to 11 years of follow-up. Multivariable Cox proportional hazards regression assessed the association between traditional risk factors and incident CAC in young (32 to 45 years), middle-aged (46 to 64 years), and older adults (65 to 84 years). A total of 61% of the participants were women and 37% were Black. The proportion with incident CAC ranged from 22% among young adults, 34% for middle-aged adults, and 45% for older adults. In young adults, traditional risk factors were significantly associated with incident CAC except for diastolic blood pressure and high-density lipoprotein (HDL) cholesterol, whereas only total cholesterol/HDL cholesterol ≥3.5 (p = 0.04) was significantly associated with incident CAC in older persons. Non-HDL cholesterol (p = 0.02) was more strongly associated with incident CAC in young (hazard ratio [HR] 1.20, 95% confidence interval [CI] 1.09 to 1.31) and middle aged (HR 1.14, 95% CI 1.07 to 1.23) compared to older adults (HR 1.11, 95% CI 0.99 to 1.23). When added to demographics, traditional risk factors provided a greater C-statistic improvement for incident CAC prediction in young (0.752, +0.070, p <0.001) versus middle-aged (0.645, +0.054, p <0.001) and older adults (0.597,+0.025, p = 0.08). In conclusion, traditional risk factors more strongly predict incident CAC in young compared to older adults, underlining the importance of primordial prevention through middle age while identifying the challenges of ASCVD risk assessment in older persons.