Obesity More Deadly for Men Than Women When COVID Strikes
It's long been known that obesity is a risk factor for severe COVID-19 in infected people. But new research suggests that the connection may be even stronger for men than women.
Researchers at Montefiore Medical Center in New York City analyzed data from more than 3,500 COVID-19 patients admitted to the hospital between early March and May 1, 2020.
Both moderate (a body mass index [BMI] of 35 to 40) and severe obesity (BMI over 40) were tied to higher rates of death for those hospitalized with COVID-19. Compared to patients at healthier weights (BMI 18 to 25), moderately obese COVID-19 patients were 44% more likely to die while in the hospital, and those who were severely obese were nearly twice as likely to die, the research showed.
But gender seemed to matter: The odds for severe pneumonia, need for a ventilator to help with breathing, and death all rose for men who were either moderately or severely obese, but in women those risks rose only for the severely obese.
The study was published May 6 in the European Journal of Clinical Microbiology & Infectious Diseases.
The researchers also looked at why obesity might worsen outcomes with COVID-19.
One theory has been an obesity-linked uptick in systemic inflammation throughout the body. So the study authors investigated if systemic inflammation -- assessed by measuring blood levels of the cytokine interleukin 6 (IL-6) -- was associated with obesity and higher risks of poor outcomes in COVID-19 patients.
"It is known that a major cause of disease severity and death is an excessive inflammatory response to SARS-CoV-2 that is associated with high levels of circulating cytokines, such as IL-6," study lead author Arcelia Guerson-Gil, of Montefiore Medical Center, said in a journal news release.
"Obesity is considered a state of enhanced chronic inflammation, so we suspected there may be an association between body mass index and systemic inflammation as indicated by IL-6 level," she said. "However, we found that this wasn't the case."
Patients who died did have higher average levels of IL-6 than survivors, men had higher average levels of IL-6 than women, and average IL-6 levels increased with age, according to the study.
But the authors found no clear association between IL-6 and obesity, which they said suggests that while inflammation may play a role in severe disease and death from COVID-19, it may not be the reason for the link between severe disease, death and obesity.
The researchers suggested other ways that obesity may increase the risk of worse outcomes in COVID-19 patients, including reduced lung function, increased effort to breathe, or higher expression in fat tissue of the ACE2 receptor, which allows SARS-CoV-2 (the virus that causes COVID-19) to enter cells.
Impaired breathing could be a possible factor, according to Dr. David Chun, who directs hospital medicine at Glen Cove Hospital in Glen Cove, N.Y.
"The study suggests that different patterns of fat distribution in men versus women could account for the increased death in men," said Chun, who wasn't involved in the research. "In other words, overweight men carry most of their fat in their abdominal region, [and that] has a detrimental effect on lung function, which is more prominent when fighting serious lung infections like COVID-19 pneumonia."
Further research is needed to confirm this study's findings, and clinical trials to assess whether drugs that target fat tissue in the abdomen and chest would improve outcomes in obese COVID-19 patients might prove useful, the study authors concluded.
The U.S. Centers for Disease Control and Prevention has more on obesity and other health conditions that increase the risk of severe COVID-19.
SOURCES: David C. Chun, MD, director of hospital medicine, Glen Cove Hospital, Glen Cove, N.Y.; European Journal of Clinical Microbiology & Infectious Diseases, news release, May 6, 2021