Is obesity one of the least talked-about risk factors for severe complications from COVID-19?
The data is not yet overwhelming, but an increasing number of doctors and public health experts are beginning to ask aloud how significant obesity is as a risk factor for complications from the coronavirus.
The CDC already considers people of any age with morbid obesity (defined as a body mass index (BMI) of 40 or above) as a “higher risk” population. But are people who are merely categorized as overweight or obese – about 70% of the adults in the United States – also at increased risk of severe COVID-19 complications?
The most dramatic evidence comes from a study of 112 Chinese COVID-19 patients, in which remarkable difference in disease outcomes based on BMI was found. 17 of the 112 patients died, and 15 of those patients were overweight (88%), whereas only 18 of the 95 survivors were overweight (19%).
This week, the United Kingdom’s National Health Service found that over three-quarters of COVID-19 patients in intensive care are overweight. This data was less striking – 62% of the nation is categorized as overweight – but still prompted much commentary:
Quite a number of us had warmed about how our diet is killing us. The stats show that almost 2/3rds of critically ill coronavirus patients are overweight.
Another critical focal point once we get COVID done @DrAseemMalhotra @JoannaBlythman https://t.co/NZLiiDJqKT
— Prof Chris Elliott OBE (@QUBFoodProf) March 24, 2020
Overweight and obese people are more likely to exhibit other coronavirus risk factors, such as hypertension and diabetes, which undoubtedly explains some of the increase in severe illness and death among patients. However, the condition may pose risks of its own. Obesity is known to suppress the immune system, and excess weight also makes it more difficult for the diaphragm and lungs to operate.
The data from other viral infections is not encouraging. Studies have shown that obese people are twice as likely to suffer illness from seasonal influenza, that they are more likely to transmit influenza, and even that excess weight makes the flu vaccine less effective. In the 2009 ‘swine flu’ pandemic, obese patients were far more likely to require hospitalization and to die.
Some have even speculated as to whether or not the comparatively slow growth of the epidemic in South Korea and Japan can be at least partially attributed to the relative fitness of the populations there. Both nations have some of the very lowest obesity rates in the world, especially among adult males, the population most likely to suffer negative COVID-19 outcomes.
The Obesity Pandemic
Even Japan and South Korea, however, are losing battles with the rise of obesity. A March 4th report by the World Obesity Federation (WOF) indicates that literally every nation on earth is experiencing rising levels of obesity.
Years ago the United Nations has set a goal to for all member nations to “halt the rise in diabetes and obesity” by the year 2025. With five years to go, that goal already seems unreachable. Not just unreachable for the world as a whole, but unreachable in every single nation individually. As the WOF report states, “all countries are worryingly off track to meet the 2025 global targets to which they have committed.”
The targets were part of an effort to reduce the prevalence of non-communicable diseases: cancer, cardiovascular disease, chronic respiratory diseases and diabetes. Obesity is a significant risk factor for all of these conditions, even many cancers, and the connection between obesity and Type 2 diabetes is well-known.
Some of the very skinniest nations are now seeing the greatest rises in obesity. In the last two decades the greatest proportional increases in obesity have belonged to countries such as Laos, Vietnam, and Rwanda, countries that still rank among the least obese but by 2025 will likely see the rates of obesity double and triple since 2010.
The rise of obesity among children is particularly concerning. Between 2010 and 2016, the rate of global childhood obesity rose from 4.9% to 6.8%, and by 2025 could be as high as 10.5%. In Vietnam, for example, a scant 1% of adolescents were found to be obese in 2010, but by 2025 that is projected to be as high as 6.8%. For reference, in the United States over 20% of adolescents (ages 5-19) are considered obese. In several nations, particularly those with comparatively lean adult populations, children are now more likely to be obese than adults.
The World Obesity Foundation declared March 4 to be World Obesity Day, but the declaration was understandably buried under the avalanche of news of the COVID-19 pandemic, which at that time had just gained a foothold in many nations outside of its origin in China. Perhaps by next year we’ll have more solid information on whether or not the novel coronavirus can be added to the list of obesity’s serious negative health consequences.