Cardiovascular Comorbidities with Alzheimer's Disease: A Systematic Review and Meta-analysis

Alzheimer's disease stands as the most prevalent form of dementia, characterized by a progressive decline in cognitive function and memory. Numerous risk factors have been linked to its development, creating a complex interplay of influences. In this study, we aim to delve into the relationship between cardiovascular disease and Alzheimer's disease, exploring how conditions affecting heart health may impact the onset and progression of this debilitating neurological disorder. Through this research, we could find potential connections that inform prevention strategies and therapeutic approaches.

We adopted the PRISMA guidelines and defined the PECOS framework as follows: Population (P) = individuals; exposure (E) = cardiovascular disease; comparison (C) = without cardiovascular disease; outcome (O) = Alzheimer's disease; and study design(S) = all kinds of studies with an association between cardiovascular disease and Alzheimer's disease without time limits. A meta-analysis was conducted using case-control, cohort, and genetic studies to estimate Odds Ratios (ORs) or Hazard Ratios (HRs).

The pooling of data in meta-analysis demonstrated that a person with any Cardiovascular Disease (CVD), Heart Failure (HF), Coronary Artery Disease (CAD), Atrial Fibrillation (AF), Hypertension (HTN), and Myocardial Infarction (MI) had more risk of developing Alzheimer's disease [CVD: HR = 1.30 (CI: 1.27-1.33) / HF: HR = 1.63 (CI: 1.37-1.94) / CAD: HR = 1.43 (CI: 1.40-1.46) / AF: HR = 1.38 (CI: 1.34-1.42) / HTN: HR = 1.22 (CI: 1,10-1.35) / MI: HR = 1.07 (CI: 1,01-1.13)]. Cross-sectional studies demonstrated an association between cardiovascular diseases and Alzheimer's disease [OR = 1.29 (CI: 1.23-1.35)]. Mendelian randomization meta-analysis did not demonstrate a causal relation between cardiovascular disease and Alzheimer's disease [AF: OR = 1.03 (CI: 1.00-1.01) / HF: OR = 1.00 (CI: 0,79-1.36)]. A Mendelian randomization meta-analysis demonstrated that a person with AD had a higher risk of developing myocardial infarction [OR = 1.07 (CI: 1.03-1.10)].

This review examines the connection between AD and CVD, noting that HF increases the risk of developing AD with a hazard ratio of 1.63. It suggests that altered brain perfusion and hypoxia appear to be one important neurodegenerative factor. Some genetic changes in individuals with CVD made them more vulnerable to AD. Effective prevention and treatment of CVD can help reduce the risk of AD.

HF, AF, and CAD were the CVDs with the highest risk of developing AD. The results suggest that changes in cerebral blood perfusion are a principal neuropathological event that leads to genetic alterations that end in AD.