Causal Insights into Plasma Lipidome and Allergic Rhinitis: Implications from a Bidirectional Two-Sample Mendelian Randomization Analysis

Abstract Plasma lipidomes regulate inflammatory responses and influence immune cell function, but the causal relationship between lipids and allergic rhinitis (AR) remains unclear. This study aimed to elucidate this relationship using Mendelian randomization (MR). Summary statistics were obtained from genome-wide association studies (GWAS) involving 179 plasma lipid subtypes and AR outcomes. Sensitivity analyses ensured robustness, heterogeneity, and absence of horizontal pleiotropy. Bayesian Weighted Mendelian Randomization (BWMR) was employed to enhance reliability. A meta-analysis further validated the findings. After FDR correction, several lipid phenotypes were identified as significant risk factors for AR, particularly phosphatidylcholine (18:0_20:4) levels, which remained significant using FinnGen data. Consistent results from MR Egger, weighted median, and BWMR methods underscored the robustness of our findings. This study suggests potential causal associations between specific plasma lipids and AR, offering new perspectives for exploring the biological mechanisms underlying AR and guiding the development of early intervention and treatment strategies.