Causal Associations Between Chronic Inflammatory Skin Diseases and Alzheimer's Disease: A Bidirectional Two-Sample...

Area of Science:

• Genetics
• Neuroscience
• Immunology

Background:

• Alzheimer's disease (AD) and inflammatory skin diseases (ISDs) share underlying immune activation.
• The direct causal relationship between ISDs and AD is not well understood.

Purpose of the Study:

• To investigate the potential causal links between inflammatory skin diseases and Alzheimer's disease using a bidirectional Mendelian randomization approach.
• To explore whether genetic predisposition to ISDs influences AD risk, and vice versa.

Main Methods:

• Utilized bidirectional two-sample Mendelian randomization with European GWAS summary data.
• Employed inverse-variance weighted (IVW), weighted median, and MR-Egger methods for analysis.
• Conducted sensitivity analyses to assess pleiotropy and heterogeneity.

Main Results:

• Significant causal effects of several ISDs on Alzheimer's disease risk were identified, including lichen planus and various forms of psoriasis.
• No evidence of a causal effect of Alzheimer's disease on inflammatory skin diseases was found.
• No significant heterogeneity or pleiotropy was detected, supporting the robustness of the findings.

Conclusions:

• Chronic skin inflammation may play a causal role in Alzheimer's disease risk, although effect sizes are modest.
• Neuroimmune mechanisms are implicated and represent potential therapeutic targets for Alzheimer's disease.
• Further research is needed to clarify the clinical implications of these findings.