A review of COVID-19 studies shows a difficult link between two health crises: coronavirus and obesity.
From COVID-19 risk to recovery, the chances are stacked against those with obesity, and a new study led by the University of North Carolina at Chapel Hill raises concerns about the impact of obesity on the effectiveness of a future COVID-19 -faxine.
Researchers examined the available published literature on individuals infected with the virus and found that those with obesity (BMI over 30) had a significantly increased risk of hospitalization (113%), more likely to be included in the intensive care unit (74 %), and had a higher risk of death (48%) due to the virus.
A team of researchers at UNC-Chapel Hill’s Gillings School of Global Public Health, including lead author Barry Popkin, a professor in the Department of Nutrition and a member of the Carolina Population Center, collaborated with senior author Meera Shekar, a health and nutrition specialist from the World Bank, on paper published in Obesity Reviews.
For the paper, researchers looked at immunological and biomedical data to provide a detailed outline of the mechanisms and pathways associated with obesity with increased risk of COVID-19, as well as an increased chance of developing more serious complications of the virus.
Obesity has been associated with a number of underlying risk factors for COVID-19, including hypertension, heart disease, Type 2 diabetes, and chronic kidney and liver disease.
Metabolic changes caused by obesity – such as insulin resistance and inflammation – make it difficult for overweight people to fight certain infections, a trend that can be seen in other infectious diseases such as flu and hepatitis.
In times of infection, uncontrolled serum glucose, which is common in individuals with hyperglycemia, can impair immune function.
“All of these factors can affect the metabolism of immune cells, which determines how bodies respond to pathogens such as the SARS-CoV-2 coronavirus,” said co-author Melinda Beck, professor of nutrition at Gillings School of Global Public Health. “Overweight people are also more likely to have physical ailments that make fighting this disease harder, such as sleep apnea, which increases pulmonary hypertension, or a body mass index that increases difficulties in a hospital setting with intubation.”
Previous work by Beck and others has shown that the flu vaccine is less effective in overweight adults. The same could be true for a future SARS-CoV-2 vaccine, Beck said.
“However, we are not saying that the vaccine will not be effective in populations with obesity, but rather that obesity should be considered as a changing factor to consider for vaccine testing,” she said. “Even a less protective vaccine will still offer some level of immunity.”
Roughly 40% of Americans are obese and the resulting closure of the pandemic has led to a number of conditions that make it more difficult for individuals to reach or maintain a healthy weight.
Working from home, restricting social visits and reducing daily activities – all in an effort to stop the spread of the virus – mean we are moving less than ever, Popkin said.
The ability to access healthy food has also received a hit. Economic difficulties put those who already eat unsafe at further risk, making them more vulnerable to conditions that may arise from consuming healthy foods.
“Not only are we more at home and experiencing more stress due to the pandemic, but we also do not visit the store as often, which means the demand for highly processed junk foods and sugary drinks that are less expensive and more shelf-stable has increased, he said. “These inexpensive, highly processed foods are high in sugar, sodium and saturated fat and loaded with highly refined carbohydrates, all of which increase the risk of not only obesity but also major non-communicable diseases.”
Popkin, who is part of the Global Food Research Program at UNC-Chapel Hill, said the findings highlight why governments should address the underlying dietary contributions to obesity and demonstrate strong public health policies to reduce obesity at the population level. Other countries, such as Chile and Mexico, have adopted policies ranging from taxing foods high in sugar to introducing warning labels on packaged foods high in sugar, fats and sodium and restricting the marketing of junk foods to children.
“Given the significant threat COVID-19 poses to individuals with obesity, healthy eating policies can play a supportive – and especially important – role in mitigating COVID-19 mortality and disease,” Popkin said.
