Stroke and Alzheimer's Disease: A Mendelian Randomization Study

Area of Science:

• Neurology
• Genetics
• Epidemiology

Background:

• Stroke and Alzheimer's disease (AD) are prevalent neurological disorders.
• Previous research suggested shared genetic factors between late-onset AD and ischemic stroke.
• The causal relationship between various stroke subtypes and AD remains unclear.

Purpose of the Study:

• To investigate the genetically causal relationship between different stroke types and Alzheimer's disease risk.
• To utilize Mendelian randomization (MR) to assess the potential causal links.
• To differentiate the impact of various stroke subtypes on AD etiology.

Main Methods:

• Employed Mendelian randomization (MR) studies to analyze genetic associations.
• Utilized inverse-variance weighted (IVW) and weighted median regression (WMR) for meta-analysis.
• Applied MR-Egger regression and intercept terms to detect pleiotropy.

Main Results:

• No statistically significant causal association was found between any stroke (AS) and AD (IVW P=0.750, WMR P=0.274).
• Analysis revealed no causal link between any ischemic stroke (AIS) and AD (IVW P=0.305, WMR P=0.487).
• Large-artery atherosclerotic stroke (LAS) and cardio-embolic stroke (CES) also showed no causal relationship with AD risk (LAS IVW P=0.568; CES IVW P=0.245).
• Pleiotropy was assessed and found to be non-significant across all analyses.

Conclusions:

• Different types of stroke, including AS, AIS, LAS, and CES, are not causally associated with an increased risk of Alzheimer's disease.
• The findings suggest that genetic factors do not support a causal link between these stroke subtypes and AD.
• Further research may explore other potential non-genetic pathways or shared risk factors between stroke and AD.