The COVID-19 pandemic is far from over. Since it started, we have learnt about the ways in which virus causes damage to our bodies and how we can manage the disease better. There have been observations from various countries that age more than 60 years, diabetes, heart disease and autoimmune diseases are risk factors for severity and increased complications of COVID-19. One more significant finding has been observed - there is a correlation with excess body weight too. This is logical because excess weight predisposes to these very diseases.
The first observation came from China in the beginning of the epidemic, when it was observed in January and February that obese patients had almost 2.5 times the risk of developing severe pneumonia. Since then observations from Italy, New York, New Orleans, France, and many other places have observed higher incidence of pneumonia and other complications in overweight and obese people. The mortality rates in COVID 19 patients admitted in intensive care is much higher if the patient's Body Mass Index (BMI) is greater than 30.
Extra weight and aging have some similarities. The immune system gets compromised in both cases and there is increased susceptibility to infections and complications. Extra weight, especially central obesity (having a bigger waistline and more abdominal / visceral fat) affects various functions of the body through many pathways. It predisposes people to
Diabetes
Heart disease
Dyslipidaemia (elevated cholesterol or fats (lipids) in the blood)
Hypertension
Chronic kidney disease
Poor functioning of lungs
Sleep apnoea
Hypercoagulability: the tendency to form clots
Cancer
Excess weight or obesity causes chronic inflammation, which is the production of chemicals in the body that are usually produced when body deals with a threat like infections or poor diet.
The link between excess weight and COVID-19 is evident. Many of the effects of COVID-19 on our body are aggravated by excess weight. Even the entry point of the coronavirus is through receptors (ACE 2 receptors), which are more prevalent in adipose tissue or fat tissue. These receptors are also present in the lungs, which we know the novel coronavirus targets causing pneumonia and lung damage. More fat tissue gives abundant entry points to the virus resulting leading to more damage. There are mechanical issues too. It is difficult to put obese people on ventilation, apart from the fact that their lung function is poorer than people with normal weight.
There is one habit which mitigates the effect of chronic inflammation - exercise and physical activity. It not only decreases the effect of chronic inflammation; it has a positive impact on patients with heart disease and diabetes too. In fact, overweight / obese people who exercise have an edge over people with normal weight who do not exercise.
Experience with earlier vaccines such as those for Influenza, Hepatitis and Rabies has shown a decreased response to the vaccine in obese people. It remains to be seen if the response to a COVID-19 vaccine will be less in these patients, which may make them vulnerable even after vaccination.
So, while we face the current pandemic, we need to brace ourselves for preventing and dealing with any new ones which may emerge. Our first line of defence from future pandemics comes from maintaining the optimal body weight and remaining fit - treatments come second. Stay Healthy, Stay Lean, Stay safe!