Gut microbiota, allergic rhinitis, vasomotor rhinitis, Mendelian randomization, causal association

Objective: Continuous research on the structure and function of intestinal microecology has confirmed the association between gut microbiota and the occurrence, development, and outcome of allergic diseases. Here, we explored the genetic causality between gut microbiota and rhinitis. Methods: We conducted a two-sample Mendelian Randomization (MR) study to investigate the genetic causal relationship between gut microbiota and allergic rhinitis and vasomotor rhinitis. Genetic variations in the human gut microbiota were obtained from the summary statistics of the MiBioGen study. Genome-wide summary statistics of rhinitis were obtained from the FinnGen consortium. The causal effect between gut microbiota and rhinitis was assessed using the inverse variance weighted, MR-Egger regression, and weighted median methods. In addition, sensitivity analyses were conducted using different methods, including maximum likelihood, simple mode, and weighted model methods. Results: The IVW approach revealed a causal association of the genus Ruminococcus gauvreauii group with an increased risk of allergic rhinitis (IVW Odds Ratio [OR = 1.26] [1.04, 1.53], p-value = 0.01645). In addition, the genus Fusicatenibacter (IVW OR = 1.20 [1.02, 1.41], p-value = 0.02868) was causally associated with an increased risk of vasomotor rhinitis. Conclusion: Gut microbiota belonging to different genera exert different effects on allergic rhinitis and vasomotor rhinitis, including reducing the risk of rhinitis, and increasing the risk of rhinitis. New insights into the mechanisms of underlying gut microbiota-associated rhinitis are provided. (c) 2024 Associacao Brasileira de Otorrinolaringologia e Cirurgia Cervico-Facial. Published by Elsevier Espana, S.L.U. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).