Asymptomatic extracranial carotid artery disease (aECAD) is associated with increased Alzheimer's disease (AD) and non-AD dementia risk. aECAD treatment includes carotid endarterectomy (CEA) and carotid artery stenting (CAS) for stroke prevention, but their impact on dementia incidence is poorly studied.

Propensity score matching was used in a retrospective cohort study of United States-based insurance claims (2010-2022) in 487,676 patients with aECAD to evaluate the effect of CEA and CAS on AD and non-AD dementia incidence.

After matching, 37,317 patients underwent CEA or CAS. CEA was associated with a significantly lower AD risk (relative risk = 0.93; 95% confidence interval, 0.86-0.99; P < 0.05), whereas CAS was associated with a slight but non-significant increase. Similar trends were observed for non-AD dementia.

CEA, but not CAS, may confer a protective effect against AD and non-AD dementia in patients with aECAD, a common cerebrovascular disease affecting up to 15% of adults over age 60.

Asymptomatic extracranial carotid artery disease (aECAD) is associated with increased Alzheimer's disease (AD) and non-AD dementia risk. Limited studies have evaluated the role of carotid endarterectomy (CEA) and (carotid artery stenting (CAS) on dementia outcomes. Using United States-based insurance claims data, 487,676 patients with aECAD were evaluated. After propensity score matching, CEA was significantly associated with reduced AD risk. CAS was not significantly associated with a change in AD risk.