TORONTO -- Data has shown that those with obesity are more likely to die or suffer more severe cases of COVID-19 if they contract the novel coronavirus, but new research presented at the European and International Congress on Obesity (ECOICO) is shedding light on why.
At the annual ECOICO -- held online this year at the start of September -- the relationship between obesity and COVID-19 was front and centre.
And for good reason: previous studies have shown that obesity is a risk factor for COVID-19, and that COVID-19 patients with obesity have a higher mortality rate than COVID-19 patients without obesity.
According to a press release on French data presented at the ECOICO, areas of France that had higher percentages of obesity “appeared to take longer to release their lockdown restrictions” due to COVID-19 still circulating in those areas.
Data from the Lille University Hospital in France from April also found that 87 per cent of the COVID-19 patients in the ICU who had severe obesity ended up needing to be put on a ventilator.
On Wednesday, new research was released at ECOICO in conjunction with a, the official journal of the European Association for the Study of Obesity, aiming to go into what is happening that makes obesity a risk factor.
Adipose tissue, commonly known as fat, is a tissue present in all humans. Fat is necessary for our survival and has a role in numerous processes within the body, including immunity and inflammation. But when this tissue builds up too much, as is the case with obesity, it can result in “chronic low-grade inflammation,” which is associated with complications such as Type 2 diabetes, cardiovascular disease, and even some cancers.
So how does fat tissue play into how COVID-19 in particular affects the body?
According to a press release on this new research, the inflammation caused by obesity releases molecules called cytokines, which trigger an immune response. This actually can leave those with obesity with an “impaired immune response to infections and increased viral loads when infected by viruses.
“In COVID-19, the attempts of the immune system to eliminate the virus produce a constant stream of these cytokines, which can lead to an effect known as the 'cytokine storm,' which can cause organ damage (e.g. lung injury), leading to poor outcomes and death,” the release explained.
How COVID-19 enters the body is also something researchers looked at in regards to obesity.
SARS-CoV-2, the virus that causes COVID-19, interacts with the angiotensin-converting enzyme-2 (ACE2), which is part of the renin-angiotension-aldosterone system (RAAS). Both SARS-CoV-2 and the SARS virus that struck Canada in 2003 can use this enzyme as a receptor to latch onto and infect individuals.
The RAAS system can regulate blood pressure and is involved in inflammation processes. In those dealing with obesity, the RAAS system is already “overactivated,” which researchers say could cause these patients to be more susceptible to not just having more severe cases, but to contracting COVID-19 in the first place.
"The collision of the obesity and COVID-19 pandemics highlights the importance of understanding shared disease pathophysiology, which may steer therapeutic choices to prevent or dampen the complications of COVID-19, especially in vulnerable populations such as people living with obesity and related chronic diseases,” said Dr. Gijs Gossens in the press release, an associate professor at Maastricht University in the Department of Human Biology.
Another study last week suggests also that vaccines could be less effective on those with obesity, particularly if they rely on spurring an immune response, which is weakened in those with obesity.
Research done on patients who have recovered from COVID-19 also showed that in many cases, they had long-lived memory T cells, suggesting that having strong T cells is important for recovery or for developing a vaccine.
“Unfortunately, as T cell responses have been shown to be impaired in individuals with obesity, this suggests that a future COVID‐19 vaccine may be less effective in an population with a high prevalence of individuals with obesity,” the August 26 study said.
The overwhelming message at ECOICO seems to be that more needs to be done to assist those with obesity.
"Several months into the COVID-19 pandemic, the increased risk posed by this virus to people living with obesity could not be clearer,” Francois Pattou, head of the Department of General and Endocrine Surgery at Lille University Hospital said in a press release.
“Our data show that the chances of increasing to more severe disease increases with BMI, to the point where almost all intensive care COVID-19 patients with severe obesity will end up on a ventilator."
