FAS (OR [95% CI] = 0.98 [0.97, 1.00], p = 4.56 ×10-2, proportion = 8.0%) and MPO (OR [95% CI] = 0.98 [0.97, 1.00], p = 2.13 ×10-2, proportion = 8.1%) partially mediated the causal effect between LTL and COVID-19 severity. Here, MPO is linked to COVID-19.