Type 1 diabetes linked to arrhythmia in Mendelian analysis

Individuals with type 1 diabetes (T1D) are at heightened risk or arrythmia, with a causal relationship between the two medical conditions demonstrated in a two-sample Mendelian randomization (MR) study.

To infer causality between T1D and arrhythmia at the genetic level, researchers used genetic variables and summary statistics from genome-wide association studies of T1D and arrhythmia. The causal effects between the two medical conditions were summarized using the inverse variance-weighted method in the primary analysis. Meanwhile, the weighted median and weighted mode methods were used as secondary methods.

The MR-Egger method was used to test for horizontal pleiotropy, while the Q-test facilitated detection of heterogeneity. A leave-one-out sensitivity analysis was performed, with scatter plots, forest plots, and funnel plots employed to visualize the results of the MR analysis.

A total of 28 T1D-related single nucleotide polymorphisms were selected as instrumental variables. Several statistical methods showed a potential causal effect of T1D on arrhythmia, as follows: inverse-variance weighted analysis (odds ratio [OR], 0.98, 95 percent confidence interval [CI], 0.97−1.00; p=0.008), weighted median analysis (OR, 0.98, 95 percent CI, 0.96−0.99; p=0.009), and weighted mode analysis (OR, 0.98, 95 percent CI, 0.96−0.99; p=0.018).

No horizontal pleiotropy was found on the MR-Egger method (p=0.649), and the Q-test showed no heterogeneity (p=0.653).