Studies have shown that obesity increases risks associated with severe COVID-19, but whether the risks vary between men and women has not been clear.
Now, new research on more than 3,500 coronavirus patients in New York shows that obesity may be a stronger risk factor for death, severe pneumonia and mechanical ventilation in men with COVID-19 than women.
The researchers speculate that the distribution of fat in men, which is located more in the central and abdominal region of the body, may explain the gender disparity. This type of fat distribution is known to have greater inflammatory properties and have negative impacts on lung function, all of which exacerbate COVID-19.
The study was published May 6 in the European Journal of Clinical Microbiology & Infectious Diseases.
“Particular attention should be paid in protecting the population living with severe obesity from SARS-CoV-2 with priority to vaccination access, remote work, telemedicine, and other measures given the higher risk of adverse outcomes once they are diagnosed with COVID-19,” the researchers wrote in the study. “In addition, patients with severe obesity diagnosed with COVID-19 should be treated with particular attention given the high risk for worse outcomes.”
The team analyzed electronic health data on 3,530 coronavirus patients admitted to the inpatient service or intensive care unit at the Montefiore Medical Center in New York between March 10 and May 1, 2020.
Patients were separated into six groups — normal/underweight, overweight, class I obesity, class II/III obesity — based on body mass index, a number calculated from a person’s weight and height.
Men with moderate and severe obesity were more likely to develop severe COVID-19, need mechanical ventilation and die from the disease, whereas only severe obesity brought these same risks among women, even after adjusting for other factors such as high blood pressure, diabetes, coronary heart disease and chronic kidney disease.
The researchers also studied whether systemic inflammation — a known cause of COVID-19 severity and death — was associated with obesity in raising risks for severe outcomes, given obesity is “considered a state of enhanced chronic inflammation,” the team said. They did this by measuring the levels of IL-6, a molecule that regulates inflammation and the production of blood cells.
Adults who died from COVID-19 had higher levels of IL-6 compared to people who survived the illness; men also had higher average levels of the molecule than women. However, there was “no clear association between IL-6 and obesity, suggesting that while inflammation may play a role in severe disease and death from COVID-19, it may not be the mechanism that underlies the association between severe disease, death and obesity.”
Different patterns of fat distribution in men and women may explain the gender disparities instead, the researchers said.
Men tend to have more fat along the central and abdominal regions of their bodies, also known as visceral fat, that surrounds the organs. This type of fat has been shown to have greater inflammatory characteristics and negative impacts on lung function by reducing “chest wall compliance.” In other words, it makes it harder to breathe.
Women have more fat lying just under the skin, called subcutaneous fat, which is not associated with higher risks for metabolic disorders.
Obesity contributed to 30% of the 900,000 adult COVID-19 hospitalizations that occurred from the pandemic onset through November 2020, according to the Centers for Disease Control and Prevention.
And the condition is becoming more common among Americans, the agency notes.
From 1999-2000 to 2017-2018, the prevalence of obesity jumped from about 31% to 42%, while the prevalence of severe obesity increased from about 5% to 9%.