Objective This study aims to evaluate the mediating effects of body mass index (BMI) on the association between obstructive sleep apnea (OSA) and hypertension using a two-sample multivariate Mendelian randomization (MR) study method.
Methods Summary statistics from publicly available genome-wide association studies were used for univariate and multivariate MR analyses to estimate the causal relationships and mediating effects of BMI. The inverse variance weighted (IVW) method was used as the main method for effect estimation, with additional methods including weighted median (WME), weighted mode (WM), MR-Egger regression, and simple mode method (SM). Heterogeneity and pleiotropy in the study were assessed using the IVW method and pleiotropy residual and outlier analysis in Mendelian randomization (MR-PRESSO).
Results The odds ratios (ORs) from univariate MR analyses regarding OSA and BMI on hypertension were 1.291 (95%CI: 1.111 to 1.500) and 1.981 (95%CI: 1.841 to 2.132) respectively. The multivariable MR analysis showed that the odds ratio for the association between OSA and hypertension was 1.051 (95%CI: 0.943 to 1.173). Further analysis indicated that BMI played a mediating role on the relationship between OSA and hypertension, with a mediation effect of 0.09 and a proportion of 34.6% (sobel-test, P＜0.001).
Conclusion OSA is a risk factor of hypertension and BMI had a mediating effect on the association.
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