Figure 1.

Description of the study design in this bidirectional MR study. (A) MR analyses depend on three core assumptions. (B) Sketch of the study design. The red represented the forward MR analyses, with critically ill COVID‐19 as exposure and LTL as the outcome. The blue represented the reverse MR analyses, with LTL as exposure and critically ill COVID‐19 as the outcome. LD, linkage disequilibrium; LTL, leukocyte telomere length; MR, Mendelian randomization; SNPs, single‐nucleotide polymorphisms.