People with obesity – regardless of age – are more likely to be hospitalized with COVID-19 and have higher risks for complications and death, according to new research.
The study, presented Tuesday at the American Heart Association's virtual Scientific Sessions, sought to shed new light "on the intersection of a global pandemic and the national epidemic of obesity," said lead author Nicholas Hendren. The research was published simultaneously in the AHA journal Circulation.
More than 42% of U.S. adults have obesity, according to the Centers for Disease Control and Prevention. It was already known that obesity can worsen the outcomes from COVID-19, increasing the risk of hospitalizations and death. But for the new study, researchers sought out more concrete data on the intersection of obesity and COVID-19, especially among younger adults.
"Younger people often think they're invincible from COVID, but we wanted to find out if that was really true," said Hendren, a cardiology fellow at UT Southwestern Medical Center in Dallas.
The study looked at data from patients hospitalized with COVID-19 at 88 U.S. hospitals taking part in the AHA's COVID-19 Cardiovascular Disease Registry. Patients with obesity were more likely to be hospitalized and had an increased risk for being put on a ventilator or dying compared to normal-weight patients. Risk progressively increased as body mass index rose.
Patients with severe obesity – those with a BMI of 40 or greater – had slightly more than double the risk of being put on a ventilator and a 26% higher risk of death compared to normal-weight patients. The mortality association was strongest in younger adults: Patients age 50 and younger with severe obesity had a 36% higher risk of death compared to their normal-weight peers.
"We didn't expect the results to be so striking for young adults," Hendren said. "If you're in your 20s or 30s or 40s, you're not bulletproof if you're severely obese."
The study also found that patients with higher BMIs, regardless of age, were at higher risk for blood clots that start in a vein – known as venous thromboembolism – and also for kidney dialysis. "We're talking about weeks to months of needing rigorous medical therapy to survive," Hendren said.
The findings underscore the importance of preventing obese people from contracting the coronavirus, no matter how young they are, he said.
"As we look potentially forward to having a vaccine in the near future, individuals who are very obese should be considered a priority to get the vaccine earlier rather than later," Hendren said.
The study was limited to data from hospital patients, so it didn't analyze the risks to all people with both obesity and COVID-19, he said. Hendren called for future studies to see if steroids or other treatments can modify the immune system of patients with obesity and help them survive COVID-19.
Dr. Sadiya Khan, who was not involved in the research, said the study tackled widespread misconceptions about the virus.
"Our perception of people hospitalized with COVID-19 has been one of elderly adults … and this study changes that conversation," said Khan, a preventive cardiologist at Northwestern University in Chicago who studies obesity's effect on heart disease. "Young adults might feel like they're immune, but this shows if you're young, obesity is an important risk factor."
Khan said the study also casts serious doubt on the concept of "herd immunity without vaccination … the idea of, 'Let's just go back to normal life and let people get (the virus) and develop antibodies by exposure.'"
She said, "Knowing that two-thirds of the population are either overweight or obese, this is a really good reminder of why herd immunity is a potentially catastrophic approach in our country."
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