Researchers at the University of Alabama in Tuscaloosa (UA) observed a statistically significant correlation between the occurrence of obesity and negative outcomes from coronavirus disease 2019 (COVID-19), according to a study published in World Medical and Health Policy.

The risk of respiratory infections and diminished pulmonary function are known to increase in patients with obesity.1,2 Some of the metabolic changes caused by obesity are insulin resistance and inflammation, both of which make fighting infections more difficult. This trend has been observed in patients with obesity when fighting other infectious diseases as well, such as influenza and hepatitis.2

Currently, patients with COVID-19 and obesity have been observed to have a higher risk of negative health outcomes in hospitals.1 In a different study led by the University of North Carolina at Chapel Hill (UNC-Chapel Hill), researchers investigated published literature and found that those with obesity, which they categorized as a body mass index (BMI) over 30, had a 113% increased risk of being hospitalized, a 74% increased risk of being admitted to the intensive care unit, and a 48% increased risk of mortality from COVID-19 infection.2

"The current global pandemic of COVID-19, which is highly contagious with presumed high mortality rates, has dramatically increased the need to understand the association between obesity and negative health outcomes from respiratory disease, particularly death," said UA study co-author Lisa Pawloski, PhD, professor of anthropology and associate dean for international programs for UA’s College of Arts & Sciences, in a press release.

In order to assess any correlation between obesity and negative health outcomes, the UA study authors used data on COVID-19 related deaths among adults aged 18 to 64 years compiled by The New York Times. They estimated morbid obesity rates among the same age range for each US county using data from the National Health and Nutrition Examination Survey and the US Census Bureau.1

The results demonstrated that morbid obesity was positively correlated with COVID-19 case rates and mortality rates. Additionally, researchers found that the rates of patients with morbid obesity can explain 9% of the variation among COVID-19 mortality rates.1

"As a matter of practical importance, with the complex interactions that are likely to produce negative COVID-19 outcomes, any single variable that can explain more than 9% of the variation is worth examining further," said study co-author Kevin Curtin, UA professor of geography, in the press release.1

Additionally, the UA study authors found that by overlaying the data geographically, areas with a high rate of obesity also had a high rate of COVID-19 mortality.1

There are short-term and long-term implications of these findings, according to the researchers. In the short term, the study results could affect treatment and policy regarding patients with COVID-19 who are morbidly obese.1 For instance, the COVID-19 vaccine itself may be less effective for those with obesity.2
The UNC-Chapel Hill study authors explained that the influenza vaccine is less effective in adults with obesity, which may have implications for the efficacy of a future COVID-19 vaccine as well.2

"However, we are not saying that the vaccine will be ineffective in populations with obesity, but rather that obesity should be considered as a modifying factor to be considered for vaccine testing," said UNC-Chapel Hill study co-author Melinda Beck, professor of nutrition at Gillings School of Global Public Health, in a press release. "Even a less protective vaccine will still offer some level of immunity."2

In the long term, the results of research into the correlation between obesity and a higher risk of mortality from COVID-19 may bring awareness to the need for more resources around issues pertaining to respiratory diseases in areas with greater occurrences of obesity.1

"The findings suggest that areas with larger obese populations will need greater resources for effective treatment of COVID-19, as more cases and deaths should be expected as compared with the general population," Pawloski said in the UA study’s press release.1

REFERENCES
  1. Relationship between COVID-19 deaths and morbid obesity. Tuscaloosa, AL: University of Alabama in Tuscaloosa; August 20, 2020. sciencedaily.com/releases/2020/08/200820143854.htm. Accessed August 25, 2020.
  2. Obesity linked with higher risk for COVID-19 complications. Chapel Hill, NC: University of North Carolina at Chapel Hill; August 26, 2020. eurekalert.org/pub_releases/2020-08/uonc-olw082420.php. Accessed August 26, 2020.