Cerebral Vasoreactivity, Apolipoprotein E, and the Risk of Dementia: A Population-Based Study

Abstract

Objective-Cerebral vasoreactivity (CVR) is a key factor in maintenance of continuous cerebral perfusion and a marker of (micro)vascular damage. We aimed to determine the longitudinal relation between CVR and the risk of dementia in the general population. Approach and Results-We determined CVR in nondemented participants who underwent transcranial Doppler with induced hypercapnia from 1997 to 1999, as part of the ongoing population-based Rotterdam Study. We used a Cox model to determine the risk of dementia in relation to CVR, adjusted for age, sex, cardiovascular risk factors, and carotid intima-media thickness. We furthermore determined decline on a cognitive test battery in relation to CVR, using linear mixed models. Among 1629 participants (mean±SD age 70.6±6.2 years, 46.2% female) with a mean follow-up of 11.5 years, 209 were diagnosed with dementia, of whom 171 had Alzheimer disease. Higher CVR at baseline was associated with lower risk of dementia (adjusted hazard ratio, 95% confidence interval, per SD increase: 0.87, 0.75-1.00) and Alzheimer disease (adjusted hazard ratio, 0.84; 0.71-0.99). This association was more profound in APOEε4 carriers than in noncarriers (adjusted hazard ratio for all dementia: 0.77, 0.60-0.98 versus 0.89, 0.73-1.07). Performance on cognitive tests at baseline was better with higher CVR (g-factor: P=0.02), but during 3 cognitive assessments over 11 years of follow-up, higher CVR at baseline was associated with less decline in test scores on the Stroop reading and interference tasks in APOEε4 carriers only (P=0.01 and 0.02, respectively). Conclusions-Impaired CVR is associated with an increased risk of dementia in the general population.