Hypertension and Cognitive Impairment: Kahrizak Elderly Study

Abstract

Background: Dementia is a major cause of cognitive impairment in the elderly. Numerous studies have investigated the association between hypertension and cognitive disorders in elderly persons, with inconsistent results. The goal of the study was to investigate the association between hypertension at baseline and cognitive impairment after 24 months’ follow-up in the elderly residents of the Kahrizak Charity Foundation (KCF) in Iran. Methods: There were 211 elderly residents of KCF aged 65 years or older with a Mini Mental State Examination (MMSE) score greater than 10. The MMSE score was assessed at the end of the study. Blood pressure was measured in all of the participants at the beginning of study. Data were compared between hypertensive and normotensive patients. Results: A total of 63.5% of patients had impaired cognition (61% and 63.9% in normotensive and hypertensive patients, respectively). Cross sectional analysis of baseline data in a multiple regression model has revealed that diastolic high blood pressure was a risk factor for cognitive impairment even after adjustment for confounding factors (odds ratio: 2.42, 95% CI: 1.01-5.78). In the cohort follow-up analysis, the relative risk of cognitive impairment for patients aged 75 years or older with final diagnosis of hypertension was 0.72 (0.57–0.92). The relative risk of patients with systolic high blood pressure and history of hypertension was 19% and 10%, respectively, which was lower than normotensive group but such differences were not significant. Conclusions: High systolic blood pressure in very old persons may have a preventive effect on development and progression of cognitive impairment. However, diastolic high blood pressure perhaps may be a risk factor for cognitive impairment in elderly persons.

Keywords

• cognitive impairment
• diastolic high blood pressure
• elderly
• systolic high blood pressure