The Causal Association Between Gastroesophageal Reflux Disease and the Risk of Allergic Asthma: Two-Sample Mendelian...

Mendelian randomization (MR) has become a powerful method for using genetic variations as instrumental variables to identify the causal relationship between risk factors and diseases.

To investigate the causal relationship between gastroesophageal reflux disease (GERD) and allergic asthma using the Mendelian randomization (MR) method.

Suitable single-nucleotide polymorphisms (SNPs) were extracted from genome-wide association study (GWAS) data on GERD as genetic instrumental variables. The causal association between GERD and allergic asthma risk was explored using the Inverse Variance-Weighted, Weighted Median, Simple Mode, Weighted Mode, and MR-Egger methods.

The results of the Inverse Variance-Weighted method (OR= 1.47, 95% CI for OR: 1.25-1.73) show a causal relationship between GERD and allergic asthma. Gastroesophageal reflux disease is a risk factor for the development of allergic asthma. The weighted median method (OR= 1.31, 95% CI for OR: 1.02-1.66) further confirmed GERD as a risk factor for the development of allergic asthma. Tests for horizontal pleiotropy, heterogeneity, and leave-one-out analysis demonstrated that the instrumental variables did not bias the results. In contrast, the results of reverse MR showed no significant causal relationship between allergic asthma and GERD (OR=1.02, 95% CI for OR: 0.93-1.11, P=0.653), and allergic asthma was not a risk factor for the development of GERD.

A positive causal relationship exists between GERD and allergic asthma. However, there is no direct effect of GERD-independent allergic asthma.