BGLAP and COVID-19: The levels of markers related to bone turnover, such as the C-terminal telopeptide of type 1 collagen (CTX-1) and osteocalcin (OC), were notably lower in COVID-19 patients than in the control group (0.172 [0.097; 0.375] vs. 0.462 [0.300; 0.649] for CTX-1, and 10.50 [6.49; 16.26] vs. 15.33 [11.85; 19.63] for OC, respectively) (Table 4).