Carotid Flow Velocities and Blood Pressures Are Independently Associated With Cognitive Function

Few studies simultaneously addressed associations between carotid flow velocities, blood pressure (BP), and cognitive function.

Subject without dementia (N = 1,684) underwent measurements of BP and biochemical markers. Mini-Mental State Examination (MMSE) and comprehensive neuropsychological tests were used to evaluate cognitive function. Peak systolic velocity (PSV) and end-diastolic velocity (EDV) were measured in common and internal carotid artery. Subjects with MMSE score of ≤24 (25th percentile) was defined as low MMSE. Multivariable linear and logistic regression were used to evaluate the relationship of cognitive function with carotid flow velocities and BP.

Carotid flow velocities (PSV: standardized β = 0.067, P = 0.0009; and EDV: standardized β = 0.067, P = 0.0021) and systolic blood pressure (standardized β = -0.061, P = 0.005) were positively and negatively associated with MMSE, respectively, in the model with adjustments for age, sex, educational attainment, nutritional status, and smoking. Similar trends were noted for the associations between flow velocities and different neuropsychological tests. By multivariable logistic regression, the group with the lowest quartile (<25th percentile) of flow velocities had increased probability of low MMSE (odds ratio: 1.538; 95% confidence intervals: 1.142 to 2.071, P = 0.0046 for PSV; and odds ratio: 1.699; 95% confidence intervals: 1.233 to 2.341; P = 0.0012 for EDV), compared to those with the highest quartile (≥75th) flow velocities.

Both low carotid flow velocity and high BP were independently and comparably associated with cognitive dysfunction.