Severe obesity is linked to a higher risk of death from the coronavirus among men, regardless of underlying health conditions

• Severe obesity may increase the risk of dying from the coronavirus even more than related factors like diabetes and socioeconomic disparities, a study suggests.
• The effect was most striking in men and people 60 and younger. Women may be protected due to the way they tend to carry weight.
• Excess body weight may make COVID-19, the disease caused by the coronavirus, more deadly due to its effects on the immune system and lung function.
• But the jury is still out on how body weight affects COVID-19, and weight stigma could be to blame for the findings, one dietitian said.

The coronavirus has hit people with obesity hard, with more and more studies linking excess weight to severe illness and hospitalizations from the disease.

It's always been possible, even likely, that medical, racial, and socioeconomic inequalities are behind the suffering experienced by people with high body mass indexes — not the weight itself.

But a study out August 12 found that the more obese a person was, the more likely they were to die from COVID-19, even when controlling for factors like underlying conditions, race, and socioeconomic status.

The risk was most "striking," the authors wrote, among men and people under 60. Women of any age with obesity weren't at any significantly higher risk of death than women who fall into the normal weight category.

The research "confirms previous reports that younger obese patients are likely to do worse, and suggests that the relationship between obesity and death from COVID-19 is not related to comorbid risk factors, or racial or neighborhood level factors," Dr. Salim Hayek, who was not involved in the study, wrote on the American College of Cardiology's website.

But not all experts agree, with one dietitian telling Insider weight discrimination may explain the findings.

People with BMIs indicating 'severe' or 'extreme' obesity were between 3 and 4 times more likely to die

For the study, researchers at Kaiser Permanente Southern California looked at data from nearly 7,000 COVID-19 patients who were treated between February and May. Almost half were obese, defined as a body mass index over 30.

Just over half were Hispanic, about 1,000 were Asian/Asian-American, and 584 were Black.

The study authors found that 3% of all patients died within 21 days of admission.

They tried to isolate the link between obesity and death by factoring out conditions like heart failure and lung disease, as well as considerations like whether they smoked or drank, and their household income and education level.

They found that, compared to people with "normal" body mass indexes, those with a BMI of 40 to 44 (considered "severe" or "extreme") were more than twice as likely to die from coronavirus complications.

For those with BMIs above 45 — a 6-foot, 335-pound person would meet this criteria — the risk was more than quadrupled.

Again, these results were most pronounced in men and those 60 years or younger, with no significant link between even extreme obesity and death among female patients.

That could be due to the way women tend to carry fat (around their hips and thighs) compared to men (around their bellies, which is linked to negative health effects), the authors say.

The added risk for younger patients may be reflective of the fact that they're less likely to have comorbid conditions like heart disease that were factored out.

The study also didn't find a significant link between race and ethnicity or neighborhood factors like population density, despite plenty of research highlighting the outsized burden minority populations face when battling COVID-19.

The lack of those disparities in the current research may be because the patients studied were members of a health care system in which clinicians receive a set fee per patient regardless of treatment, and so had "more equalized health care access," the authors write.

Excess weight can restrict breathing, which can be dangerous with a condition like COVID-19

Prior research has shown overweight and obesity are linked with a higher rate of hospitalizations and complications from the coronavirus.

The potential reasons are multifold and complicated, but many experts point to excess body fat's ability to impact the immune system and lung function.

Particularly among people who carry their body fat around the middle, obesity can activate inflammation and weaken the body's anti-inflammatory response, making them more susceptible to illness, research suggests.

Extra weight around the chest and in the belly can also physically restrict breathing, which can be dangerous with a condition that largely affects the respiratory system like COVID-19.

Weight stigma could also play a role in the findings

Christy Harrison, an anti-diet registered dietitian who hosts the Food Psych podcast, told Insider the study still does not prove obesity is an independent risk factor for COVID-19.

She suspects a lot of the findings can be explained by weight stigma, which is linked to negative health outcomes and which is strongest against people at the high end of the BMI spectrum, like those the study found most at risk.

"I think it's likely that much of the increased risk found in this study for men with BMIs of 40 and above would disappear if the researchers had been able to control for weight stigma," Harrison said.

Past research on the 2009 H1N1 pandemic that at first linked obesity with a higher risk of complications was faulty, she pointed out, with later research finding the association was eliminated when researchers accounted for the fact that smaller-bodied H1N1 patients were more likely to get better treatment.

She suspects a similar finding will emerge for COVID-19.

Ultimately, Harrison said, "the jury is very much still out," with another study finding that Black and Hispanic people are significantly more likely to contract COVID-19, but that those in the obese category are actually 17% to 18% less likely to get the illness.

"It just shows that this data is still emerging and we can't draw any hard-and-fast conclusions about body size and COVID risk," she said.

But the study authors say there's enough evidence to inform decisions about coronavirus patients with obesity, regardless of race or underlying conditions early in the triage process.

"As COVID-19 continues to spread unabated, we must focus our immediate efforts on containing the crisis at hand," they wrote. "Yet our findings also underscore the need for future collective efforts to combat the equally devastating, and potentially synergistic, force of the obesity epidemic."

• Read more:
• Doctors are bracing for the coronavirus pandemic to meet America's obesity epidemic
• 'Obesity' should be defined by a person's health, not just their weight, Canada doctors say
• A new hands-off weight loss program helped people lose more pounds than they would in intensive courses, a study found
• An entire town in New York is being put on a diet to prevent obesity-related coronavirus complications