Low systolic blood pressure increases risk of allergic rhinitis: Evidence from a bidirectional Mendelian randomization study accounting for smoking environment

Abstract

Allergic rhinitis (AR) is one of the most common diseases in adults. Dust and secondhand smoke in the air can both trigger AR and elevated blood pressure. The objective of this study was to assess the impact of systolic blood pressure (SBP) on the risk of AR using a bidirectional two-sample Mendelian randomization (MR) framework. Summary-level genome-wide association study data for SBP and AR were retrieved from the MR-Base platform. Single-nucleotide polymorphisms (SNPs) associated with SBP as exposure at genome-wide significance p<5×10-8 and exhibiting low linkage disequilibrium r2<0.001 were selected as instrumental variables. Bidirectional two-sample MR analyses were performed using the inverse-variance weighted method (IVW), weighted median estimator, and MR-Egger regression to estimate associations between both directions. A total of 421 independent SNPs associated with SBP were included in the forward MR analysis. All three methods consistently indicated that genetically lower SBP is associated with an increased risk of AR (IVW odds ratio, OR=0.9997; 95% CI: 0.9995–0.9999; weighted median OR=0.9998; 95% CI: 0.9995–1.0001; MR-Egger OR=0.9996; 95% CI: 0.9990–1.0001). Reverse MR analysis provided no evidence that genetic liability to AR influences SBP. These findings provide genetic evidence for a relationship in which lower systolic blood pressure increases susceptibility to allergic rhinitis.