Covid-19 and Obesity, a High Risk Equation Questions and Answers

Is overweight, obesity an increased risk if you suffer from Covid-19? Reports of hospital beds with overweight people have followed in several countries, and several studies confirm it: Obesity increases the risk of Covid-19 patients being admitted and even going to intensive care. However, the science is less conclusive about the increased risk of death. At least in Portugal, obese people don’t seem to have a higher risk of death because they suffer from Covid-19.

Is Obesity Making Covid-19 More Serious?
There are many studies linking obesity to more severe cases of Covid-19 that require hospitalization and more aggressive treatment. In August, a meta-analysis of 75 studies in English and Chinese, which included a database of 399,000 patients and published in Obesity Reviews, concluded that people with obesity problems are 46% more likely to get the virus infect. SARS-CoV-2.

And the risk that people with a body mass index (BMI) greater than 30 – the ratio between a person’s height and weight – will be classified as obese and require hospital treatment is 113%, concluded the study, lead author Barry Popkin is from the University of North Carolina (USA) and the World Bank. These people are still 74% more likely to end up in intensive care – and 48% more likely to die.

Vasco Ricoca Peixoto of the Center for Integrated Health Research at the National School of Public Health of the Universidade Nova de Lisboa emphasizes that he prefers to speak of “adjusted risks” rather than percentages in order to take into account the variables that can confuse one Analysis. However, based on Portuguese data, it is confirmed that obesity is the main risk factor for making SARS-CoV-2 infection worse. “It is only surpassed by 60-year-olds. In other words, obesity increases the risk of being hospitalized 1.6 times and those between the ages of 60 and 69 increase that risk twice, ”he told the PUBLIC.

Patient in the intensive care unit at the Beatriz Ângelo hospital in Loures Miguel Manso / PÚBLICO

“People who are obese are more likely to have a more serious illness, possibly with greater difficulty breathing. It is one of the most important factors for hospitalization in the intensive care unit, ”explains the Portuguese researcher.

If the BMI exceeds 25, the World Health Organization considers the person to be overweight and if they go beyond 30 it is considered obese. If the BMI is equal to or over 40, it is considered severe obesity. And during this pandemic year, hospitals around the world were filled with patients with obesity problems who were seriously affected by Covid-19.

In the UK’s first wave of infections early last year, 70% of ICU patients were obese or overweight. The effect was mainly felt in people between the ages of 55 and 74 who lived in poor areas, and in some groups (blacks, Asians, and ethnic minorities), confirming the social dimension of obesity as a disease, often shared with disadvantaged populations has been linked, says a study by Public Health England (equivalent to the Directorate-General for Health).

Does Obesity Increase The Risk Of Dying From Covid-19?

International studies have shown an increased risk of death from Covid-19 in overweight people. Barry Popkin’s team identified an increased risk of 48%. However, Vasco Ricoca Peixoto’s studies on patients treated in Portuguese hospitals do not confirm this increase. “Among Covid-19 patients who have to be hospitalized, overweight people are more likely to be admitted to the intensive care unit. However, people who are hospitalized are no longer at risk of death, ”he says.

Vasco Ricoca Peixoto, at the request of the PUBLIC, performed a real-time analysis to check whether the database of 16,000 hospitalized patients he works with has a higher risk of death for overweight patients under 1,800 who had to be admitted to the intensive care unit. That didn’t happen.

“Among those in intensive care units, the greatest risk factors for mortality are age (three times more from 60 to 69 years, five times more from 70 to 79, seven times more from 80 to 89 years, seven times more for people older than 90 ) “, Said Vasco Ricoca Peixoto. “People with obesity are more likely to experience serious situations in which they need assistance, but obesity alone does not increase the risk of death.”

“The comorbidities that increase the likelihood of death more strongly are malignant neoplasms, heart disease, kidney disease, respiratory disease, liver disease and neurological disease,” the researcher concludes. “High blood pressure or diabetes are not in themselves a risk factor.”

What are the risk factors for hospitalization with covid-19?

Being older and male are generic risk factors for Covid-19. The median age of hospital patients in several countries is between 47 and 73 years, and 60% are men, according to an article published in January in Nature Reviews, lead author Norbert Stefan of the Diabetes Research Institute and Metabolic Diseases at the Helmholtz Center, Munich.

Obesity is an important risk factor that has been confirmed by several studies, although these authors were not recognized early on. Its importance was not recognized until April 2020, writes the team. “The first studies to report the characteristics of patients with Covid-19 showed that the main comorbidities were hypertension, diabetes, cardiovascular disease, chronic obstructive pulmonary disease, chronic kidney disease, cancer and chronic liver disease,” the explain Scientist.

However, a pre-existing illness can be a risk factor in itself. Although only 25% of the patients infected with the SARS-CoV-2 virus suffer from comorbidities, 60% to 90% of the people who have to be hospitalized already suffer from illnesses, according to Norbert Stefan’s team.

Of all the diseases that are considered risk factors for Covid-19, obesity is the most common: almost all countries today have a prevalence of over 20% of overweight or obese people. The latest data available in Portugal from 2014 registered 3.5 million overweight people and one million overweight people.

How do obese people become more susceptible to Covid-19?

There is no clear cause and effect explanation yet, but several posts to explain this. Obesity biology has several factors that seem tailored to the disease caused by the new coronavirus to create havoc in the body, such as: B. the weakening of the immune system and chronic inflammation. Additionally, obese people’s blood tends to clot too easily, which is bad because Covid-19 causes multiple cardiovascular symptoms, explains an article in the journal Science.

On the one hand, fat cells infiltrate the organs that make the cells of the immune system, and these are less effective in destroying the cells that the coronavirus infects and turning into factories to make copies of themselves, explained Science Melinda Beck, one of the study’s authors in obesity ratings. Adipose tissue, on the other hand, produces chemical messages called cytokines that trigger an inflammatory response – a process that can turn into a deadly storm in Covid-19 patients, in which the body is destroyed by the immune system protecting it from infection.

If clots form in the lungs of Covid-19 patients, the situation may get worse. “In a healthy person, the endothelial cells of the blood vessels usually say to the circulating blood: ‘Don’t clot’. But that message seems to be changed by covid-19, ”Beverley Hunt, a researcher at Guy’s and St. Thomas’ Hospital in London, told Science. “And the blood of obese Covid-19 patients is the most viscous that I have ever seen.”

We all have on the surface of several ACE2 receptor organs – angiotensin converting enzyme – that works like the lock that coronavirus spike protein fits, the key it uses to enter our cells and convert them into factories the copies made of themselves are spreading the infection. However, the number of ACE2 receptors varies from person to person and also from tissue to tissue. It occurs in the lungs, nose, mouth, but also in blood vessels, kidneys, liver and the gastrointestinal system in the heart. Overweight people and people with other comorbidities such as high blood pressure, diabetes, and coronary heart disease may have higher levels of the ACE2 receptor, which could explain their increased susceptibility.

But are overweight people more easily infected?

No, says Daniel Drucker of the Lunenfeld-Tanenbaum Research Institute at the University of Toronto (Canada), author of another study report, this time published in the journal Cell Metabolism. For example, a study in New York of 5700 hospital patients found that 41.7% were obese – when the average number of obese people in New York is 22%, says Barry Popkin’s team.

But it is a complete analysis of the variables, and to be useful it takes a lot of adjustments, stresses Vasco Ricoca Peixoto. “For example, do obese people protect themselves more? Are they becoming more social for some reason? It’s difficult to weigh exposure to the virus and the context so we can determine whether obese people are more likely to be infected. And if we manage to adjust to whatever is very difficult, I can tell if obese people with the same exposure to the virus have a more symptomatic infection – because the asymptomatic one in most cases goes untested, ”he concludes.

Should people with obesity be higher in the priorities of the Portuguese vaccination program against Covid-19? You are in the second phase, starting in April.

“Logistically, it would have been very difficult to integrate obesity into the first phase,” says Vasco Ricoca Peixoto. “Age remains the most important risk factor for hospitalization and death,” he said.

And then obesity is all too common. “My idea is that 10% to 20% of the Portuguese population will be obese, which means it will be a very common comorbidity. It would not be expected that we would be able to vaccinate this group more or less homogeneously in the first phase, ”he replies. “If I put a group in the first phase that is 20% of the population, that’s a little wrong because some of them are just vaccinated … I don’t know when,” he comments.

Large populations cannot be at the center of the priority vaccination. “On the other hand, obesity does not increase the risk of death as much, but above all a risk of hospital stays and overloading the health services,” he explained.