Data suggests that there is an association between obesity and more severe COVID-19 illness, particularly in those with a BMI of 35 or greater and age under 60.
By Dr. M Shafi Kuchay
It has become increasingly clear that older adults (above 65 years of age) and individuals of any age who have underlying medical conditions are at higher risk for severe illness and death from COVID-19. However, data is also piling up for obesity being another considerable risk factor for serious illness with COVID-19, particularly among younger patients.
Studies say
According to a recent study published in the journal Obesity, among 124 patients admitted with COVID-19 to an intensive care unit (ICU) in France, 47.6 percent had obesity (defined as a body mass index or BMI of greater than 30 kg/m2). Around 85 percent of those with severe obesity (a BMI of greater than 35 kg/m2) ended up being placed on a ventilator. In fact, patients with severe obesity were 7.4 times more likely to have been put on a ventilator compared to those with no obesity (a BMI of less than 25 kg/m2). Being placed on a ventilator means that your lung function has worsened to a point that you can no longer get enough oxygen while breathing by yourself.
According to another New York study, obesity seems to be particularly a risk factor for young people with COVID-19. Among those under 60, patients with obesity (a BMI between 30 and 34) were twice as likely to be admitted to ICU compared to patients with a BMI of less than 30. This likelihood increased to 3.6 times in those patients with a BMI of 35 or greater.
Taken together, the data suggests there is an association between obesity and more severe COVID-19 illness, particularly in those with a BMI of 35 or greater and age under 60. This is the reason US Centers for Disease Control and Prevention (CDC) now lists ‘severe obesity’ as a risk factor for serious COVID-19 illness.
Working out the connection
The mechanisms that connect obesity with severe COVID-19 illness are not clearly known but are believed to be multifaceted since obesity itself is the result of a complex interaction between genetic, social, and environmental factors.
Obesity restricts the expansion of your lungs and thus the amount of air that you can inhale. Obesity around the abdomen compresses the chest, making it more difficult for the diaphragm to move and the lungs to expand and take in air. This contributes to lower levels of oxygen in the blood, which can worsen the symptoms of COVID-19.
You may have noticed an individual with obesity gets breathless even with slightly more than usual activity. However, the good news is that reducing body weight can improve lung function. This has been seen in patients who underwent bariatric surgery and subsequent weight loss.
Obesity also affects your body’s defense system (immune system) that tries to ward off invaders (such as viruses). For instance, obesity impairs the functioning of immune cells (such as macrophages) such that these cells became less efficient in overcoming the infection. In simple terms, obesity makes the immune cells sick.
Obesity disrupts the cascade of chemicals (cytokines) that regulate your immune response. This disruption could actually lead to more inflammation in your lungs and your airway that carry air through your lungs. This is analogous to a battle between two forces (body’s immune cells and the virus), in which there is more collateral damage (to lungs, kidneys, blood vessels, and so on).
There are other challenges that patients with severe obesity might face and affect their outcomes from COVID-19. For instance, it is difficult to intubate and perform imaging (x-rays and CT scans) in patients with obesity; it is difficult to position ventilated patients with severe obesity on their stomachs (this position increases the amount of oxygen entering the lungs) and so on.
Having said that, this should not prompt those with obesity to resort to crash dieting, which may do more harm than good. The pandemic offers a good opportunity to make conscious, healthy choices and cultivate new habits to reduce your risk of illness and to enhance health and wellbeing. It is also important to understand that if you are obese, you need to take extra precautions to ensure that you don’t contract the virus.
(The author is Senior Consultant Endocrinologist, Medanta The Medicity, Gurugram, India)
