Carotid artery ultrasound grayscale median and incident dementia: The Multi-Ethnic Study of Atherosclerosis (MESA)

Introduction: Vascular contributions to cognitive impairment and dementia are potentially modifiable. Early detection of reversible arterial injury may improve risk stratification and provide treatment monitoring. We hypothesized that carotid ultrasound grayscale median (GSM), a novel imaging biomarker of early arterial injury, would predict incident all-cause dementia in the Multi-Ethnic Study of Atherosclerosis (MESA). Methods: The MESA enrolled adults free of atherosclerotic cardiovascular disease. Common carotid GSM was measured at baseline. Incident all-cause dementia events were identified by hospital and death records. Cox proportional hazards models with natural cubic splines investigated the association of baseline GSM and all-cause dementia. Results: The 1788 participants were a mean (SD) 63.1 (10.3) years old and 53% were women. Over a median 13.7 years, 157 all-cause dementia events occurred. In fully adjusted models, with additional adjustment for carotid intima–media thickness, lower (worse) GSM independently predicted incident all-cause dementia (hazard ratio, 1st to 3rd tertile, 1.45 [95% CI, 1.11–1.90], p = 0.021). Conclusions: Lower GSM independently predicts all-cause dementia, beyond traditional arterial injury measures, suggesting it may serve as an early marker of dementia risk.