Associations between Retinal Artery/Vein Occlusions and Risk of Vascular Dementia

Background: Vascular disease is a risk factor for Alzheimer's disease (AD) and related dementia in older adults. Retinal artery/vein occlusion (RAVO) is an ophthalmic complication of systemic vascular pathology. Whether there are associations between RAVO and dementia risk is unknown. Objective: To determine whether RAVOs are associated with an increased risk of developing vascular dementia or AD. Methods: Data from Adult Changes in Thought (ACT) study participants were analyzed. This prospective, population-based cohort study followed older adults (age =65 years) who were dementia-free at enrollment for development of vascular dementia or AD based on research criteria. RAVO diagnoses were extracted from electronic medical records. Cox-regression survival analyses were stratified by APOE ?4 genotype and adjusted for demographic and clinical factors. Results: On review of 41,216 person-years (4,743 participants), 266 (5.6%) experienced RAVO. APOE ?4 carriers who developed RAVO had greater than four-fold higher risk for developing vascular dementia (Hazard Ratio [HR] 4.54, 95% Confidence Interval [CI] 1.86, 11.10, p=0.001). When including other cerebrovascular disease (history of carotid endarterectomy or transient ischemic attack) in the model, the risk was three-fold higher (HR 3.06, 95% CI 1.23, 7.62). No other conditions evaluated in the secondary analyses were found to confound this relationship. There was no effect in non-APOE ?4 carriers (HR 1.03, 95% CI 0.37, 2.80). There were no significant associations between RAVO and AD in either APOE group. Conclusion: Older dementia-free patients who present with RAVO and carry the APOE ?4 allele appear to be at higher risk for vascular dementia.