Abstract
The present study was aimed at assessing the relationships between absolute and individual residual blood pressure (BP) variability and cognitive function in a general population. This cross-sectional study evaluated cognitive function using minimental state evaluation (MMSE) in 471 subjects enrolled in the PAMELA study. MMSE was calculated 10 years after initial enrollment of the subjects in the PAMELA study. Measurements included office, home, and 24-hour ambulatory BP monitoring. BP variability was obtained by calculating: (a) 24-hour standard deviation (SD) for systolic and diastolic BP and (b) individual residual BP variability. Mean age (±SD) of the subjects enrolled was 63 ± 5.7 years at the initial evaluation, with a 10-year increase when MMSE was performed. There was no significant difference in BP or heart rate values measured at office, home, or during 24-h BP monitoring between subjects with MMSE < 24 and those with ≥24. BP variability measured by SBP and DBP SD was also similar between these two groups. However, individual residual BP variability was significantly greater in subjects with lower MMSE and this difference became more pronounced when the study population was divided in three groups according to MMSE score (10-20, 21-23, 24-30). Individual residual SBP and DBP variability gradually decreased with the increase in MMSE score. Our data show that a sensitive parameter for the development of cognitive impairment is not BP or absolute BP variability but rather its short-term erratic component, which has been previously shown to be an important prognostic marker for organ damage, cardiovascular, and all-cause mortality.