The dynamics of blood pressure and cognitive functioning: results from 6-year follow-up of an elderly cohort.

The association between blood pressure (BP) and cognitive functioning in the elderly is still under debate. Theoretically, high BP could either prevent or enhance cognitive impairment. The authors assessed the changes that took place in BP and cognitive functioning over 6 years. A total of 318 noninstitutional elderly (81% of the survivors) were re-evaluated. BP was measured and a cognitive test was performed. Elderly patients who had higher systolic BP (SBP) and scored lower on the Mini-Mental State Examination (MMSE) at baseline were less likely to survive. At follow-up, the proportion of patients with normal or normalized BP by treatment increased. Considerable changes in SBP were observed. Most cognitive functions declined during follow-up; however, decline in SBP was associated with better verbal fluency and memory. Both an increase and a decline in SBP were associated with better MMSE scores. Changes in diastolic BP (DBP) were less evident and DBP was not related to cognitive functioning. The current study demonstrates the importance of studying the dynamics of both BP and cognition over time. It appears that transition from hypertension to normotension improves cognitive functions. Survival processes may restrict the evaluation of the BP-cognition interaction over time.