Abstract 9187: Risk Factors for the Onset of Coronary Artery Calcium in Younger versus Older Persons

Abstract

Introduction: Modifiable traditional atherosclerotic cardiovascular disease (ASCVD) risk factors (RFs) have a decreased predictive strength with higher ages. Whether the strength of relationship between these RFs and incident coronary artery calcium (CAC) changes with age is unknown. Hypothesis: Modifiable traditional ASCVD RFs will have a weaker association with incident CAC in older versus young adults. Methods: There were 5108 CARDIA and MESA participants without clinical ASCVD and baseline CAC=0. Repeat CAC scoring occurred 10 years later in CARDIA and 3-11 years later in MESA. Multivariable Cox proportional hazards regression calculated hazard ratios and C-statistics for RFs with incident CAC in young (32-45 years), middle-aged (46-64 years) and older adults (65-84 years). Results: A total of 61% of adults were women and 37% were African American. The proportion with incident CAC increased from young (22%) to middle-aged (33%) and older adults (45%). All modifiable traditional RFs were significantly associated with incident CAC except for diastolic blood pressure and HDL-C in young adults, whereas among older adults only a total cholesterol/HDL-C > 3.5 (p=0.04) was significantly associated with incident CAC. Systolic blood pressure was the modifiable RF with the strongest association per 1 standard deviation change for incident CAC in young adults (HR=1.29, 95% CI: 1.13-1.48), conferring lower risks in middle-aged (HR=1.20, 95% CI: 1.06-1.36) and older adults (HR=1.10, 95% CI: 0.96-1.27). Modifiable traditional RFs provided a greater improvement in the C-statistic for incident CAC prediction in young versus middle-aged and older adults ( Table ). Conclusion: Modifiable traditional ASCVD RFs were stronger predictors of incident CAC for young compared to older adults, which may be due to their higher prevalence with increasing age. Further research is needed to examine whether nontraditional RFs improve incident CAC prediction in adults > 65 years old.