BMI drives causal relationship of sleep apnoea, snoring with T2D

Body mass index (BMI) appears to be the main mediator of the association of sleep apnoea and snoring with type 2 diabetes (T2D), suggests a study.

“The possible indirect effects of sleep apnoea and snoring on T2D through BMI cannot be ruled out,” according to the researchers.

This study sought to explore the causal relationship of sleep apnoea and snoring with T2D while examining the role of BMI using five genetic methods. These methods included the following: two-sample; bidirectional univariable Mendelian randomization (MR) inverse variance-weighted (MR-IVW); multivariable MR-IVW; network MR; and latent causal variable method.

Using the largest genome-wide association study, the odds ratio of T2D for genetically predicted sleep apnoea and snoring, compared with univariable MR-IVW, significantly decreased from 1.61 (95 percent confidence interval [CI], 1.16‒2.23) to 1.08 (95 percent CI, 0.59‒1.97) and from 1.98 (95 percent CI, 1.25‒3.13) to 1.09 (95 percent CI, 0.64‒1.86) after adjusting for BMI.

On network MR, BMI was responsible for 67 percent and 62 percent of the total of effect of sleep apnoea and snoring on T2D, respectively.

“The latent causal variable suggested that sleep apnoea and snoring have no direct causal effect on T2D,” the researchers said.