How much does hypertension affect cognition?: explained variance in cross-sectional analysis of non-demented community-dwelling individuals in the SEARCH study.

Vascular pathology impairs cognition and impaired cognition increases the risk of dementia. Hypertension is arguably the vascular risk factor that can be reverted best. Here we estimated the effect magnitude of hypertension by determining the variance in cognition explained by systolic blood pressure (sBP) in non-demented community-dwelling individuals. We recruited 525 individuals (mean age 65, range 40-85) selected from the city registry of Muenster, Germany, measured cognitive performance with a comprehensive test battery and assessed vascular risk based on glycosylated hemoglobin, serum cholesterol, high sensitive C-reactive protein, body mass index, smoking pack years, and blood pressure. Including gender and education as well as the vascular risk factors, multiple linear regression analysis for different age groups showed that in midlife age groups systolic blood pressure explained up to 11% of the variance in cognitive performance. These findings suggest that in non-demented community-dwelling individuals hypertension may account for one tenth of cognitive impairment and thus for an increased risk for dementia.