NEW YORK (Reuters Health) – Higher diastolic blood pressure is independently associated with impaired cognitive function in otherwise healthy middle-aged and older adults, new research suggests.

Findings from cross-sectional and longitudinal population-based studies investigating the relation between BP and cognitive status have yielded mixed results, Dr. Georgios Tsivgoulis from University of Alabama, Birmingham and colleagues note in the August 25 issue of Neurology.

They analyzed data on 19,836 adults without prior stroke or transient ischemic attack enrolled from December 2003 to March 2007 in a longitudinal population cohort study evaluating stroke risk. The mean age of the study subjects was 64.6 years, 42.3% were black and 39.2% male.

Impaired cognitive status was present in 1,505 individuals (7.6%) and 9,844 (49.6%) were on antihypertensive medication.

In unadjusted models, systolic, diastolic, and pulse pressure were all associated with cognitive impairment.

Higher diastolic BP levels remained associated with impaired cognitive status after adjustment for demographic and environmental characteristics, vascular risk factors, depressive symptoms and current use of antihypertensive medication.

In the final multivariable logistic regression model, a 10-mm Hg increment of diastolic BP was associated with 7% higher odds of cognitive impairment, according to the authors.

The authors note that in a recent longitudinal study, higher diastolic BP was the only BP variable that predicted increased atrophy of brain structures affected by Alzheimer