The current review critically analyzes obesity as an important risk factor for increased predisposition towards coronavirus disease 2019 (COVID-19), its severity and causal death in current pandemic. Countries with higher prevalence of exposed obese individuals experienced the highest number of mortalities. The analysis also proved that individuals having more adipose tissue in body have a higher level of angiotensin-converting enzyme 2 (ACE2), which is identified as functional receptor for COVID-19. Therefore, obese individuals are worse in condition because of a higher presence of adiposity increases the number of ACE2 expressing cells. Furthermore, in silico interactions of ACE2 and different variants of coronavirus 2 (CoV-2) spike S1 protein suggest that mutant strains are more infectious than wildtype as they bind to host ACE2 protein with high binding affinities. Certain specific cancers including cervical cancer, pancreatic and rectal adenocarcinomas have more expression of such receptors and pose additional risk to already immunocompromised cancer patients. This review emphasizes obesity, as the covert risk factor of COVID-19 infection and sensitizes about of calorie restrictions, immunity building and preventive measures.
Keywords: Angiotensin-converting enzyme 2; COVID-19; Comorbidities; Protein-protein interaction; Spike protein.