Higher BMI related to increased risk of SARS-CoV-2 infection

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2), causes severe disease in high-risk populations. These include the elderly and those with underlying health conditions such as diabetes, hypertension, heart disease and obesity.

Researchers at the University of Miami Miller School of Medicine, USA, found that peak-specific immunoglobulin G antibodies in obese people are negatively associated with body mass index (BMI) and serum levels of proinflammatory and metabolic markers of lung inflammation.

The study, published in the pre-printed journal medRxiv *, also found that higher BMI is related to a higher rate of SARS-CoV-2 infection.

Obesity and COVID-19

SARS-CoV-2 is actively spreading worldwide. It has infected more than 78 million people and killed more than 1.71 million. Information on human immune responses to SARS-CoV-2 infection is limited.

However, recent studies have shown that some people are more likely to become infected and develop a more severe disease than others. Older adults and those with comorbidities are more likely to develop severe COVID-19. Recently, studies have also shown that obesity can predispose a person to severe COVID-19.

Recently published data have shown that low-level chronic systemic inflammation, called inflammation, is the leading cause of SARS-CoV-2-induced cellular and molecular changes. It is also responsible for the highest mortality rates.

Persistent obesity-induced local and systemic inflammation has contributed to impaired immune cells and reduced immunity.

Inflammation found in obese people leads to several debilitating chronic diseases, including cancer, atherosclerosis, type 2 diabetes and inflammatory bowel disease. Obesity is an additional risk factor for severe COVID-19.

The study

To reach the study’s findings, the researchers evaluated the effects of obesity on the secretion of SARS-CoV-2 specific IgG antibodies in the blood of patients with COVID-19.

The team measured serum levels of SARS-CoV-2 Spike-specific IgG antibodies in patients with weak and obese COVID-19, as well as in uninfected controls, using an enzyme-linked immunosorbent assay (ELISA).

First, the study found that BMI was higher in patients with SARS-CoV-2 positive compared to uninfected controls. This suggests that higher BMI is associated with severe respiratory symptoms. During hospitalization, those with higher BMI have severe respiratory symptoms, such as cough, fever, difficulty breathing and hypoxia, or low oxygen levels.

The results of the study also showed that peak-specific IgG antibodies in obese people are negatively related to BMI and serum levels of proinflammatory and metabolic markers of inflammation and lung inflammation.

The data collected could contribute to the development of an inflammatory signature with a strong predictive value for immune dysfunction, which can be used as a therapeutic target for improving humoral immunity among obese people.

Another result of the present study is the negative association of SARS-CoV-2 IgG antibodies with markers of lung inflammation (SAA, CRP, ferritin) in our cohort of patients with COVID-19 ”, the researchers explained.

They are the main inflammatory mediators and markers of inflammatory lung damage in patients with catastrophic acute respiratory distress syndrome, which is a primary consequence of COVID-19, they added.

Research results suggest that influenza-like SARS-CoV-2 infection can induce the breakdown of self-tolerance to autoantigens in obese people. It is essential to consider them as a high-risk group, which is more likely to develop severe symptoms due to COVID-19.

Furthermore, the quality of the antibody response in obese patients with COVID-19 is crucial for future vaccination efforts to prevent SARS-CoV-2 infection and the associated complications of COVID-19. Obese people can also benefit if they are among the first to receive a vaccination.

*Important Note

medRxiv publishes preliminary scientific reports that are not evaluated by colleagues and therefore should not be considered conclusive, guide clinical practice / health-related behavior or treated as established information.