Abstract Body: Background: Obstructive sleep apnea syndrome (OSA) frequently coexists with hypertension, with 30% to 70% of OSA patients also having hypertension. Conversely, the incidence of OSA in hypertensive patients ranges from 30% to 50%. This study designs a bidirectional Mendelian randomization trial to explore the causal relationship between OSA and hypertension.
Methods: The summary data for OSA were sourced from a recent large-scale genome-wide association study (GWAS) meta-analysis, which included 16,761 OSA patients and 201,194 European-ancestry controls from the Finnish biobank. Five SNPs were selected as instrumental variables (IVs) for OSA. The summary data for hypertension were obtained from the UK Biobank GWAS, which included 124,227 hypertension patients and 337,653 European-ancestry controls, making it the largest hypertension dataset in GWAS. From this dataset, 214 SNPs were selected as IVs for hypertension. Multiple MR methods, primarily the inverse variance weighted (IVW) method, were used for analysis. Sensitivity analyses of the MR results were performed using methods such as MR-Egger, and the F-statistic was used to evaluate the IVs.
Results: OSA was associated with an increased risk of hypertension (OR=1.053, 95%CI 1.019-1.089, P<0.01), and hypertension was significantly associated with an increased risk of OSA (OR=1.812, 95%CI 1.354-2.425, P<0.001). There was heterogeneity in the bidirectional results (OSA → hypertension, P<0.001; hypertension → OSA, P<0.001), but no horizontal pleiotropy (OSA → hypertension, P=0.666; hypertension → OSA, P=0.556). The selected IVs for OSA and hypertension were strong (OSA-IVs F=14.695; hypertension-IVs F=39.624).
Conclusion: This bidirectional MR analysis confirms the causal relationship between OSA and hypertension, with hypertension having a more pronounced effect on the incidence of OSA. OSA patients should regularly monitor their blood pressure and undergo routine physical examinations to detect hypertension early.