This observational study utilizes a bidirectional two-sample Mendelian randomization (MR) analysis to examine the causal association between allergic rhinitis and asthma. The genetic data for allergic rhinitis were obtained from the UK Biobank, encompassing 18,934 cases and 64,595 controls, while asthma data were derived from a Finnish biobank, including 20,629 cases and 135,449 controls. The Mendelian randomization analysis was performed using inverse-variance weighting (IVW), Mendelian randomization-Egger (MR-Egger), and weighted median methods to ensure robust causal inference. Additional tests, such as Cochrane's Q test and Mendelian randomization pleiotropy residual sum and outlier (MR-PRESSO), were applied to assess heterogeneity and pleiotropy, enhancing the reliability of the findings. The results are expected to provide insights into the bidirectional causal relationship between allergic rhinitis and asthma, potentially informing future prevention and treatment strategies.
