key: cord-288526-5zag3krb
authors: Sathish, Thirunavukkarasu; Kapoor, Nitin
title: Normal weight obesity and COVID-19 severity: A poorly recognized link
date: 2020-10-21
journal: Diabetes Res Clin Pract
DOI: 10.1016/j.diabres.2020.108521
sha: 
doc_id: 288526
cord_uid: 5zag3krb

nan

People with obesity (those with high body mass index (BMI)) and coronavirus disease 2019 are at increased risk of requiring intensive care admission and mechanical ventilation, and death [1] . Although BMI is a commonly used measure of obesity in clinical settings, it cannot delineate fat-free mass from adipose tissue [2] . Thus, people with normal weight on the BMI scale can have elevated body fat percent, particularly in the visceral area, an entity called normal weight obesity (NWO) [2, 3] . Indeed, emerging evidence shows that visceral adiposity, independent of BMI, is associated with a high risk of critical illness in patients with COVID-19 [4, 5] . Identifying NWO individuals, who are at high risk for metabolic dysregulation and cardiometabolic disorders [3, 6] , is often and easily overlooked in clinical practice, where screening for obesity is based solely on BMI [3] .

Reports from the USA and the UK show that South Asians, Blacks, and other ethnic minorities are more likely to contract COVID-19 and experience severe forms of illness compared with white populations [7, 8] . While this could be due to differences in socioeconomic, cultural, or lifestyle factors [8] , the role of excess body fat cannot be ignored. South Asians and Blacks generally have a higher body fat percent than whites for a given level of BMI [9, 10] . Several potential mechanisms for poor COVID-19 outcomes in obese people, including endothelial dysfunction, insulin resistance, immune dysfunction, and chronic inflammation, are directly related to excess amounts of body fat [11] . Moreover, certain key cytokines involved in the pathogenesis and disease progression of COVID-19, such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) [12] , are also synthesized in adipose tissue [13] . These cytokines are elevated in individuals with increased body fat, irrespective of their BMI [3] . Thus, adipose tissue can act as a reservoir for the virus, leading to increased and prolonged viral shedding [11] .

The use of the sagittal image of chest computed tomography (done routinely to diagnose COVID-19 pneumonia) to assess visceral adiposity [7, 8] , along with BMI, is a promising strategy to identify NWO individuals in clinical settings. Understanding the association between NWO and COVID-19 disease severity could inform better risk stratification and management of COVID-19 patients, especially those of South Asian and African origins.

Declaration of competing interest: None declared.

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Computed Tomography Highlights Increased Visceral Adiposity Associated With Critical Illness in COVID-19

The role of visceral adiposity in the severity of COVID-19: Highlights from a unicenter cross-sectional pilot study in Germany

Prevalence of normal weight obesity and its associated cardio-metabolic risk factors -Results from the baseline data of the Kerala Diabetes Prevention Program (KDPP)

The impact of ethnicity on clinical outcomes in COVID-19: A systematic review

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Funding: None.Author contributions: TS conceived the idea, conducted literature search, and draft the first version of the manuscript. NK reviewed and edited the manuscript. Both authors approved the submission of the manuscript.