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Summary
Background:
There is wide, largely unexplained, heterogeneity in immunological and clinical responses to SARS-CoV-2 infection. Numerous environmental chemicals, such as persistent organic pollutants (POPs) and chemical elements (including some metals, essential trace elements, rare earth elements, and minor elements), are immunomodulatory and cause a variety of adverse clinical events. There are no prospective studies on the effects of these substances on the incidence of SARS-CoV-2 and COVID-19 infection.
Aim:
To investigate the influence of blood concentrations of POPs and elements measured several years before the pandemic on the development of SARS-CoV-2 and COVID-19 infection in individuals from the general population.
Methods:
We carried out a prospective cohort study in 154 individuals from the general population of Barcelona. POPs and elements were measured in blood samples collected in 2016–2017. SARS-CoV-2 infection was detected by rRT-PCR on nasopharyngeal swabs and/or by antibody serology using eighteen isotype-antigen combinations measured in blood samples collected in 2020-2021. We analyzed the associations between contaminant concentrations and SARS-CoV-2 infection and the development of COVID-19, taking into account personal habits and living conditions during the pandemic.
Results :
Several historically prevalent POPs, as well as arsenic, cadmium, mercury, and zinc, were not associated with COVID-19 or SARS-CoV-2 infection. However, DDE (adjusted OR = 5.0 [95% CI: 1.2–21]), lead (3.9 [1.0–15]), thallium (3.4 [1.0–11] ) and ruthenium (5.0 [1.8–14]) were associated with COVID-19, as were tantalum, benzo(b)fluoranthene, DDD, and manganese. Thallium (3.8 [1.6–8.9]) and ruthenium (2.9 [1.3–6.7]) were associated with SARS-CoV-2 infection, as was lead , gold and (protectively) iron and selenium. We identified mixtures of up to five substances from various chemical groups, with all substances independently associated with the results.
Conclusions:
Our results provide the first prospective, population-based evidence of an association between individual concentrations of some contaminants and COVID-19 and SARS-CoV-2 infection. POPs and elements may contribute to explaining the heterogeneity in the development of SARS-CoV-2 and COVID-19 infection in the general population. If associations are confirmed as causal, means are available to mitigate the corresponding risks.
Comments
Having high levels of some chemical contaminants in the blood is related to a greater risk of suffering from SARS-CoV-2 infection and developing COVID-19, according to a scientific study by researchers at the Hospital del Mar Medical Research Institute (IMIM-Hospital del Mar), of the Barcelona Institute for Global Health (ISGlobal), a center promoted by the “la Caixa” Foundation, the University of Las Palmas and the CIBER of Epidemiology and Public Health (CIBERESP), Obesity and Nutrition (CIBEROBN) and Infectious Diseases (CIBERINFEC). The work is published in the journal Environmental Research and is the first prospective study in the world that analyzes data obtained before the pandemic on blood levels of contaminants in healthy people.
The results of this work provide a possible new explanation for the fact that there are large differences between people in susceptibility to SARS-CoV-2 infection and COVID-19. Why under conditions of exposure similar to the virus do some people become infected and others not, why do some develop the disease and others not? Today, these observations and questions remain largely without sufficient scientific explanation. “What the study observes is that some of these contaminants increase the risk of being HIV positive and having the disease ,” says Dr. Miquel Porta, one of the main authors of the study and researcher at IMIM-Hospital del Mar. Other factors that influence these differences between people are the diseases that a person already suffered from (the more comorbidity, the greater the risk of COVID-19), smoking, age, educational level, the density of people in a home or exposure to the virus on public transport or at work.
The researchers had frozen blood samples from 240 healthy people from the general population of Barcelona obtained in 2016. They have related the blood levels of contaminants in these people with the frequency of SARS-CoV-2 infection and the incidence of COVID-19. 19 during 2020-2021 in the same people. And they have observed that in cases with higher blood levels of some contaminants, the risk of infection and developing the disease was greater. In relation to the risk of COVID-19, those responsible are DDD and DDE (derivatives of the insecticide DDT), as well as lead, thallium, ruthenium, tantalum, benzofluoranthene and manganese. The risk of infection was greater the higher the blood levels of thallium, ruthenium, lead and gold, while it was lower the higher the concentrations of iron and selenium.
“ An also very relevant finding of the study is that it identifies mixtures of up to five substances, from various chemical groups, each of which increases the aforementioned risks ,” adds Gemma Moncunill, ISGlobal researcher and last author of the article.
The authors consider that these results have “considerable scientific and social relevance” , offering the first prospective evidence based on a healthy general population of a possible link between personal concentrations of some contaminants and SARS-CoV-2 infection and the COVID-19.
These contaminants reach our body through multiple routes, such as electronic devices and their use in feed in intensive livestock farming. For this reason, the study points out that “if it is confirmed that the associations found are causal, there are policies to control the corresponding risks . ”
Reference article
Miquel Porta, José Pumarega, Magda Gasull, Ruth Aguilar, Luis Henríquez-Hernández, Xavier Basagaña, Manuel, Judith Villar, Cristina Rius, Sneha Mehta, Marta Vidal, Alfons Jimenez, Laura Campi, Joan Lop, Octavio Pérez Luzardo, Carlota Dobaño i Gemma Moncunill.
Individual blood concentrations of persistent organic pollutants and chemical elements, and COVID-19: a prospective cohort study in Barcelona.
Published in Environmental Research , a journal from Elsevier publishing house classified in the ’top ten’ (top decile [D1]) of its category.
https://www.sciencedirect.com/science/article/pii/S0013935123002116
