Introduction: Vascular risk factors (VRFs) predict incident dementia. Coronary artery calcium (CAC), capturing cumulative VRFs exposure, may predict dementia beyond VRFs.
Hypothesis: In a community-based sample, baseline CAC is associated with incident dementia independent of VRFs assessed at baseline and APOE-ε4 genotype.
Methods: Among 6,814 participants of the Multi-Ethnic Study of Atherosclerosis (MESA), aged 45-84 years at baseline (2000-2002), we first identified candidate cases for incident all-cause dementia using hospital and death certificate ICD codes. For the analyses, we limited to cases whose diagnosis was validated using following criteria: 1) verifiable medical records available, 2) unlikely alternative diagnosis (e.g. delirium), and 3) written dementia diagnosis. Baseline CAC was categorized according to Agatston score (0, > 0 to <50, 50 to <100, 100 to <400, and ≥400). Cox models were used to obtain hazard ratios (HRs) adjusted for demographics, VRFs, APOE-ε4, and incident stroke prior to dementia diagnosis.
Results: We had complete data on 6,295 individuals for analysis with a mean follow-up of 11.1 years (208 validated cases). Crude rates of dementia were greater with higher baseline CAC categories. Adjusted HR of dementia per one higher CAC category was 1.14 (95%CI 1.03, 1.26) (see Table). The associations were similar when excluding interim incident coronary heart disease, or cardiovascular diseases, or using a model that accounted for competing risk of death with no dementia diagnosis.
Conclusion: Higher CAC score measured at baseline was independently and significantly associated with increased risk of dementia. This finding is consistent with an important role for vascular injury in development of dementia.