Blood Pressure and the Risk of Dementia: A Dose-response Meta-analysis of Prospective Studies

Background: A number of epidemiological studies have revealed a controversial correlation between Blood Pressure (BP) and the risk of dementia, hindering translation of research into preventative practice. Objective: To meta-analyze the dose-response relationship of dementia and its subtypes to BP. Method: Relevant studies were identified via a systematic retrieval analysis in electronic databases from inception to May 1, 2017. Linear and non-linear dose-response meta-analyses were conducted to evaluate the effects of BP on dementia risk. Results: Twenty-three studies from 17 articles with 830631 participants and 4384 cases for all dementia, 17 studies from 12 articles with 1707445 participants and 3481 cases for Alzheimer's disease (AD) and 11 studies from 8 articles with 1693690 participants and 1067 cases for Vascular Dementia (VD) were included. We identified that the associations between BP and dementia varied with population characteristics. A nonlinear relationship was found between systolic blood pressure (SBP) and all dementia risk in population-aged >= 65 years (p(nonlinearity) <0.05). SBP between 110 and 120 mmHg played a protective role in population aged 62 to 82; while SBP above 162 mmHg would significantly increase the risk in those aged 70 to 86.5. It is also noteworthy that there is a linear association between diastolic blood pressure (DBP) and AD risk in the population aged >= 65 years, such that the risk decreased by 3% for per 10 mmHg increase in a specific range of DBP. Conclusion: These findings indicate that BP management strategy for dementia prevention might be tailored according to specific population characteristics.