Obstructive Sleep Apnea Found to Increase Risk of Sick Sinus Syndrome, unravels study
A recent study revealed that individuals with an inherited susceptibility to obstructive sleep apnea (OSA) are at increased risk for developing sick sinus syndrome (SSS), a bradyarrhythmia involving the heart's own pacemaker. The study was conducted by Chen W. and fellow researchers published in the journal Nature and Science of Sleep.
OSA is a prevalent sleeping disorder that features recurring blockage of the airway while one is asleep and subsequent periods of intermittent lack of oxygen. SSS, on the other hand, refers to a wrong rhythm of the heart due to defective sinoatrial node function that leads to dizziness, drowsiness, and syncope. Both these diseases have risks of effects on cardiovascular performance, thus it is vital to identify whether one directly affects the other while designing prevention strategies and treatment procedures.
To establish the causal relationship between OSA and SSS, the researchers used a bidirectional two-sample Mendelian randomization (MR) strategy. The technique utilizes genetic differences as instrumental variables to assess causality between an exposure (OSA) and an outcome (SSS), thus eliminating confounding factors.
Genetic information on OSA were accessed from FinnGen genome-wide association studies with a sample of 410,385 participants. Equivalently, SSS association data were from deCODE genetics with a population base of 1,000,187 individuals. The group used various statistical methods for ensuring robustness such as inverse-variance weighting (IVW), MR-Egger regression, weighted median estimation, maximum likelihood, and MR-PRESSO for sensitivity analysis and identification of pleiotropy.
Key Findings
The main MR analysis with IVW (fixed effects) found a 49.3% higher risk of SSS among those genetically at risk of OSA (OR = 1.493; 95% CI: 1.120–1.990; P = 0.006). This was calculated on the basis of 7 single nucleotide polymorphisms (SNPs) as instrumental variables.
The MR-Egger intercept value of −0.002 (SE 0.030; P = 0.930) provided no indication of horizontal pleiotropy, such that the observed association was not likely to be confounded by genetic effects. The global test for pleiotropy (P = 0.719) also confirmed this result.
Reverse MR analysis indicated that there was no reverse causality—i.e., SSS did not predict an increased risk for OSA development (OR = 0.997; 95% CI: 0.926–1.072; P = 0.930).
This Mendelian randomization study presents strong evidence of a causal association between obstructive sleep apnea and elevated risk of sick sinus syndrome, based on large-scale genetic information from more than a million people. These findings underscore the importance of increased awareness and active management of OSA to potentially lower the burden of cardiac conduction disorders in the population.
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