IGF1 and COVID-19: A previous study analyzing risk factorsfor COVID-19-related mortality in people over 90 years found thatHDL-cholesterol and other blood biomarkers such as 25-hydroxyvitaminD and IGF-1 were the most significant blood biomarkers of mortality. Also, other studies have reported low levelsof total HDL- and LDL-cholesterol in the plasma of COVID-19 patients. These alterations, along with the increasedabundance of C-reactive protein (CRP), have been linked to COVID-19severity and mortality,, possibly contributingto the nonsurvival outcome in the infected nonagenarian patients (Figures  and C).