This study analyzes the prevalence of factors that increase the risk of severe manifestations of COVID-19, such as old age, chronic disease, obesity and smoking, among others. The proportion of the most susceptible people is 80% among those with less schooling (photo: Paulo Humberto / Wikimedia Commons)

Published on 03/23/2021

By Karina Toledo  |  Agência FAPESP – More than 50% of Brazilian adults, or 86 million people, have at least one of the factors that increase the risk of developing severe manifestations of COVID-19, according to a study conducted at the Federal University of São Paulo (UNIFESP). The proportion of individuals under 65 that is susceptible to complications if infected by the novel coronavirus SARS-CoV-2 is still high (47%).

To reach this conclusion, the researchers analyzed risk factors identified by early studies of the disease in Asian countries that were also observed in more recent research conducted in Europe and the United States.

“Initially, we included in the at-risk group people who are at least 65 years of age, people with chronic disease [cardiovascular disorders, diabetes, high blood pressure and chronic obstructive pulmonary disease] and cancer patients who were diagnosed at least five years previously. The latest studies, however, propose new risk factors, including dialysis and other treatments for chronic kidney disease, obesity, moderate or severe asthma, and smoking,” said Leandro Rezende, a professor in the Preventive Medicine Department at the UNIFESP Medical School (Escola Paulista de Medicina) and principal investigator for the study. A report on the findings will be published soon in Revista de Saúde Pública.

To estimate the size of the group at highest risk of COVID-19 in Brazil, the UNIFESP researchers used data from 51,770 participants in the National Health Survey (PNS) conducted in 2013 by IBGE, the census and statistics bureau in Brazil. The PNS collected information from more than 80,000 households, such as weight, height, waist circumfeand blood pressure, as well as urine and blood samples for laboratory analysis from a cross-section of the study population.

“Unfortunately, this is the most recent survey with all the information needed for our analysis. The most recent PNS was started in 2019 and has yet to be completed. It should be stressed that a lack of public investment in surveys as large as this makes it very hard to do the kind of precise analysis public policymakers require in a time of crisis like the present,” Rezende said.

A comparison of the PNS findings with data from more recent surveys, such as the 2018 health ministry nontransmissible chronic disease risk factor survey (Vigitel) covering state capitals and the Federal District, shows little change in the prevalence of diabetes (6.9% in 2013 and 7.7% in 2018) and high blood pressure (21.5% in 2013 and 22.1% in 2018 among men), while the prevalence of smoking fell from 14.4% to 12.1%, Rezende noted. On the other hand, the prevalence of obesity rose from 17.5% to 19.8%, and the prevalence of aging-related chronic diseases also rose.

“The size of the at-risk group may have been underestimated by our study, making the maintenance of physical distancing measures even more necessary, at least until seroprevalence studies [which estimate the proportion of the population that has been infected and has developed antibodies against the coronavirus] show that such measures can be safely relaxed,” he added.

Inequality

Among adults whose educational attainment consisted only of primary school, representing the low-income portion of the survey sample, the prevalence of risk factors for severe COVID-19 was twice as high as that among adults with a university degree.

“We were shocked by the numbers, even though social inequality in Brazil is a well-known fact,” Rezende said. “Almost 80% of adults with a low level of schooling can be included in the at-risk group compared with 46% of adults with higher education. The prevalence of diseases is highest among vulnerable individuals who live in places where physical distancing is difficult, have precarious jobs and have less access to healthcare services. This is a major concern.”

When the researchers analyzed the data state by state, they found the at-risk groups to be proportionately largest in Rio Grande do Sul (58.4%), followed by São Paulo (58.2%) and Rio de Janeiro (55.8%). Amapá (45.9%), Roraima (48.6%) and Amazonas (48.7%) – three states of the North Region – were better off in terms of risk.

“There are two possible explanations for this difference,” Rezende said. “One is the longer life expectancy in the South and Southeast regions, where incomes are higher and there are more older people. The other is reduced access to medical diagnosis in the North and Northeast, which may have skewed the prevalence data for diabetes and high blood pressure, as these are often asymptomatic in the earlier stages.”

In any event, Rezende concluded that the data for individual states can be used by policymakers as a guide for the prevention and control of COVID-19. “For now, the numbers emphasize the importance of maintaining physical distancing measures practically everywhere in Brazil,” he said.

 

Source: https://agencia.fapesp.br/33257