Abstract
Low Diastolic Blood Pressure and High Blood Pressure Variability are Risk Factors for Cognitive Decline in Elderly Adults: A Case-Control Study
Author(s): Chia-Chi Chen, Jia-Fu Lee, Yu-Lin Ko, Chun-Te Lee, Yue-Cune ChangBackground
This study investigated the association between visit-to-visit blood pressure (BP) variability and cognitive decline in elderly adults over a 4-month period.
Methods
All 94 elderly volunteers were recruited from a community center. Mini-Mental Status Examination (MMSE) and Clinical Dementia Rating (CDR) questionnaires were administered during the initial assessment and at 4 months after the service. The BP at each visit and the visit-to-visit BP variability were measured for 4 consecutive months.
Results
The middle-stage/moderate cognitive impairment (MMSE scores ≤ 21) group exhibited significantly lower minimum diastolic BP and higher diastolic coefficient of variation values than did the mild/no cognitive impairment (MMSE scores >21) group did. After adjustment for the effects of age, the minimum diastolic BP was significantly and positively associated with the MMSE scores (P=0.033). To further evaluate the effects of low diastolic BP (LDBP) on cognitive function, we compared the initial and 4-month MMSE scores between the LDBP group (minimum diastolic BP ≤ 50 mmHg) and the control group (minimum diastolic BP>50 mmHg). We divided the volunteers into the following 4 groups: (1) hypertension history with LDBP (HT-c-LDBP), (2) hypertension history without LDBP (HT-s-LDBP), (3) no hypertension history without LDBP (nHT-s-LDBP), and (4) no hypertension history with LDBP (nHT-c-LDBP). The cognitive function differed significantly among the four groups (MMSE scores: HT-c-LDBP=21.62 ± 2.87; HT-s-LDBP=25.20 ± 2.78; nHT-s-LDBP=26.12 ± 3.65; and nHT-c-LDBP=23.27 ± 3.16). Compared to the nHT-s-LDBP group, the data showed that the HT-c-LDBP group exhibited significantly worse cognitive function, followed by the nHT-c-LDBP group.
Conclusions
LDBP and high diastolic BP variability are risk factors for cognitive function decline in elderly adults.