Bidirectional two-sample mendelian randomization analysis identifies a causal relationship between major depressive...

Area of Science:

• Genetics and Psychiatry
• Epidemiology
• Immunology

Background:

• The association between major depressive disorder (MDD) and allergic diseases (ADs) is noted but lacks conclusive causal evidence.
• Bidirectional two-sample Mendelian randomization (MR) is employed to investigate potential causal links.

Purpose of the Study:

• To explore the causal relationship between MDD and ADs using MR.
• To determine if genetic susceptibility to MDD influences the risk of developing allergic asthma (AAS), allergic rhinitis (AR), and atopic dermatitis.
• To assess if ADs causally influence the risk of MDD.

Main Methods:

• Summary statistics for MDD were obtained from the Psychiatric Genomics Consortium.
• Single nucleotide polymorphisms (SNPs) for AAS, AR, and atopic dermatitis were extracted from the FinnGen Consortium.
• Inverse variance weighted (IVW) method was the primary analysis tool, supplemented by other MR methods and sensitivity analyses for heterogeneity and horizontal pleiotropy. Reverse MR was also performed.

Main Results:

• A nominally significant association was found between MDD and an increased risk of AR (OR=1.191, p=0.042).
• A causal relationship was established between genetic susceptibility to MDD and AAS (OR=1.418, p=0.000022) after outlier removal, with results passing sensitivity tests.
• No causal effect of MDD on atopic dermatitis was detected (OR=1.049, p=0.53).
• Reverse MR analysis did not support a causal link from ADs to MDD.

Conclusions:

• The study suggests a nominally significant causal relationship between MDD and an increased risk of AR.
• A specific causal relationship between MDD and AAS is indicated.
• Further validation of these findings is necessary.