The link between obesity and COVID-19

Exploring the nexus between critical manifestations of COVID-19 and preexisting conditions can be daunting.

Ladders has been tracking medical expertise on the subject ever since the coronavirus responsible for the devastating respiratory disease penetrated the US earlier this year.

In that time, studies have identified a wide range of bio-markers educative of case severity. According to the Center for Disease Control and Prevention, the following underlying disorders are reliably associated with COVID-19 hospitalization.

  • Cancer
  • Chronic kidney disease
  • COPD (chronic obstructive pulmonary disease)
  • Immunocompromised state (weakened immune system) from solid organ transplant
  • Obesity (body mass index [BMI] of 30 or higher)
  • Serious heart conditions, such as heart failure, coronary artery disease, or cardiomyopathies
  • Sickle cell disease
  • Type 2 diabetes mellitus

Obesity has always stood out among these, even if the reasoning was largely undetermined up until this point.

Thankfully, a new study published in the International Journal of Obesity provides key insights into the most common comorbidity in SARS-CoV-2 transmission.

“Overweight and obesity are major risk factors for diabetes, cardiovascular disease, and lung disease. These diseases are the most commonly reported health conditions that predispose individuals with SARS-CoV-2 infection to require hospitalization including intensive care unit admissions,” the authors wrote in the new report. The innate immune response is the host’s first line of defense against a human coronavirus infection. However, most coronaviruses are armed with one strategy or another to overcome host antiviral defense, and the pathogenicity of the virus is related to its capacity to suppress host immunity.”

The Louisiana State University researchers behind the paper are fairly confident that the hormone, leptin places populations at a higher risk for severe forms of COVID-19.

Patients infected with SARS-CoV-2 who are also overweight consistently develop low-grade systemic inflammation. Moreover, these tend to evidence a stilted immune response compared to patients of healthy weights.

“If you have obesity, there are a number of underlying health issues that make it more difficult for you to fight off a COVID-19 infection,” study co-author John Kirwan, PhD, Pennington Biomedical Executive Director explained in a media release.  “Your entire body, including your lungs, may be inflamed.  Your immune response is likely compromised, and your lung capacity reduced. Add in a virus that further weakens the body’s ability to fight infection, that can limit the body’s ability to control lung inflammation, and you have the recipe for disaster.”

In addition to helping us regulate energy levels after meals, leptin is believed to affect our auto-immune response. The more fat we have in our body, the higher the amount of leptin in our cells, the higher the amount of leptin in our cells the weaker our defense against sophisticated infections.

This is perhaps an oversimplification, but more research needs to be done in order to elevate the minute details.

The authors revealed that the lungs are particularly vulnerable in the wake of a surplus of metabolic hormones.

As COVID-19 progresses, affected osrgans become inflamed over time. For some, this results in ventilator assistance and sometimes even death.

“We propose that leptin may be the link between obesity and its high prevalence as a comorbidity of the SARS-CoV-2 infection. In this article, we present a synthesis of the mechanisms underpinning susceptibility to respiratory viral infections and the contribution of the immunomodulatory effects of obesity to the outcome.” the authors continued.

The authors hope their analysis inspires vaccinologists to widen the scope of their research.

Ideally, disproportionately impacted communities will be protected by antigens in the very near future.