Higher BMI associated with 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. This includes the elderly and people with underlying health problems, such as diabetes, hypertension, heart disease and obesity.

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

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

Obesity and COVID-19

SARS-CoV-2 is actively spreading worldwide. It 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 serious illness 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 showed that chronic low-grade systemic inflammation, called inflammation, is the main cause of the cellular and molecular changes induced by SARS-CoV-2. It is also responsible for the highest mortality rates.

The persistent local and systemic inflammation induced by obesity contributed to the impairment of immune cells and reduced immunity.

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

The study

To arrive at the results of the study, the researchers evaluated the effects of obesity on the secretion of specific IgG antibodies to SARS-CoV-2 in the blood of patients with COVID-19.

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

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

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

The collected data can help to develop an inflammatory signature with strong predictive value for immune dysfunction, which can be used as a therapeutic target to improve humoral immunity among obese people.

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

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

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

In addition, 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 complications associated with COVID-19. Obese people can also benefit if they are among the first to receive a vaccine.

* Important news

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