Obstructive Sleep Apnea and BMI, Body Fat Percentage in the East Asian Population: A Bidirectional and Multivariate...

To explore the causal relationship between obstructive sleep apnea and body fat percentage and body mass index (BMI) in the East Asian population by using bidirectional Mendelian randomization and multivariate Mendelian randomization.

We utilized genetic data on obstructive sleep apnea and BMI from the NBDC database in Japan and body fat percentage data from the Biobank in Taiwan, China. Obstructive sleep apnea cases were identified using ICD-10 diagnostic codes rather than PSG data. Concurrently, body fat percentage and BMI were inferred from genetic variants rather than from actual body fat percentage or BMI measurements. Bivariate and multivariate Mendelian randomization analyses assessed the causal relationship between obstructive sleep apnea and obesity. The Inverse Variance Weighted method was used as the main Mendelian randomization analysis method.

In this study, we found that for the East Asian population (a) the forward causal relationship between body fat percentage and obstructive sleep apnea was significant (Inverse Variance Weighted: β 1.272, 95% CI 0.288-2.257, p = 0.011); (b) the forward causal relationship between BMI and obstructive sleep apnea was also significant (Inverse Variance Weighted: β 0.817, 95% CI 0.217-1.417, p = 0.008); (c) however, neither the reverse causal relationship between obstructive sleep apnea and body fat percentage (Wald ratio: β -0.018, 95% CI -0.041 to 0.005, p = 0.127) nor that between obstructive sleep apnea and BMI (Inverse Variance Weighted: β 0.003, 95% CI -0.021 to 0.026, p = 0.833) was significant. Furthermore, multivariate Mendelian randomization analyses suggested that the effect of body fat percentage on the risk of obstructive sleep apnea was independent of BMI.

Both body fat percentage and BMI are strong risk factors for obstructive sleep apnea, and body fat percentage can function independently of BMI. Body fat percentage may be able to be used as a new indicator for screening and diagnosis of obstructive sleep apnea.