Obesity and COVID-19: what makes obese host so vulnerable?

Abstract

The disease (COVID-19) novel coronavirus pandemic has so far infected millions resulting in the death of over a million people as of Oct 2020. More than 90% of those infected with COVID-19 show mild or no symptoms but the rest of the infected cases show severe symptoms resulting in significant mortality. Age has emerged as a major factor to predict the severity of the disease and mortality rates are significantly higher in elderly patients. Besides, patients with underlying conditions like Type 2 diabetes, cardiovascular diseases, hypertension, and cancer have an increased risk of severe disease and death due to COVID-19 infection. Obesity has emerged as a novel risk factor for hospitalization and death due to COVID-19. Several independent studies have observed that people with obesity are at a greater risk of severe disease and death due to COVID-19. Here we review the published data related to obesity and overweight to assess the possible risk and outcome in Covid-19 patients based on their body weight. Besides, we explore how the obese host provides a unique microenvironment for disease pathogenesis, resulting in increased severity of the disease and poor outcome.

Keywords: Coronavirus; Covid-19; Inflammation; Innate and adaptive immunity; Insulin resistance; Obesity.

Fig. 1

Dysregulated fatty acid metabolism, cellular hypertrophy and death, ER stress, Hypoxia and mitochondrial dysfunction, because of excess fat leads to a substantial alteration of cellular architecture of adipose tissue. This rearrangement favors a pro-inflammatory environment and perpetuates local as well as systemic inflammation

Fig. 2

Factors responsible for disease severity and poor outcome in obese COVID-19 patients. Obesity-associate chronic inflammation, impaired Immune function and increased ACE2 expression results in an increased disease severity and worse clinical outcome in obese subjects with COVID-19 infection