La contaminación atmosférica se asocia a una mayor duración de síntomas de la COVID persistente
Exposure to air pollutants (PM2.5 and P.M.10) is associated with a longer duration of long COVID symptoms, in part due to its impact on the severity of acute infection. This is the main conclusion of a study led by the Barcelona Institute for Global Health (ISGlobal), a center promoted by the ”la Caixa” Foundation, in collaboration with the Germans Trias i Pujol Research Institute (IGTP), and published in Environmental health perspectives.
The persistence of COVID is a heterogeneous disease in which symptoms such as fatigue, shortness of breath, and cognitive problems persist for months after a COVID-19 infection and cannot be explained by other diagnoses. The true burden of long COVID is still uncertain, but it is estimated to affect millions of people around the world. Its risk factors are also not well understood, since even people with mild or asymptomatic symptoms during acute infection can develop long COVID.
“We previously showed that exposure to air pollution is related to an increased risk of severe illness from COVID-19 and a decreased response to the vaccine, but there are very few studies on the effect of the environment on persistent COVID,” he explains. Manolis KogevinasISGlobal researcher. In this study, he and his colleagues investigated whether air pollution and other environmental exposures, such as noise, artificial light at night, and green spaces, were associated with the risk—or duration—of long COVID.
The study followed more than 2,800 adults from the COVICAT cohortbetween 40 and 65 years old who lived in Catalonia and who completed three online questionnaires (2020, 2021 and 2023) during the pandemic. These surveys collected information on COVID-19 infections, vaccination status, health status, and sociodemographic data. Additionally, the research team calculated residential exposure to noise, particulate matter, ozone, nitrogen dioxide, green spaces, and artificial nighttime light for each participant.
Risk factors for long COVID
The analysis showed that one in four people who contracted COVID-19 experienced persistent symptoms for three months or more, and 5% experienced symptoms that lasted for two years or more. Women, people with lower educational levels, those with pre-existing chronic conditions, and those who had severe COVID-19 were at higher risk of developing persistent COVID. Vaccination, on the other hand, had a positive impact: only 15% of vaccinated participants developed persistent COVID, compared to 46% of unvaccinated ones.
Air pollution and persistence of symptoms.
The exposure to particles in the air (PM2.5 and P.M.10) commits to a slight increased risk of COVID long lasting persistent (i.e., people who reported having long COVID in 2021 and whose symptoms were still present in the last week before the 2023 interview). The risk of long-lasting persistent COVID increased linearly with higher levels of exposure to particulate matter. On the other hand, factors such as proximity to green spaces or traffic noise barely influenced the duration of persistent COVID.
The research team notes that while air pollution may not be a direct cause of long COVID, it could increase the severity of the initial infection, which in turn increases the risk of long COVID. “This hypothesis is supported by the association between suspended particles and the most severe and long-lasting cases of persistent COVID, but not with all cases,” he says. Apolline Saucyfirst author of the study.
More research is needed to break down the different types of persistent symptoms and get a more detailed picture of how environmental factors may play a role. “These types of studies are especially relevant as more people continue to recover from COVID-19 and deal with its potential long-term effects,” Kogevinas says.
About COVICAT
The COVICAT cohort is a COVID-19 population-based cohort designed to characterize the health impact of the COVID-19 pandemic on the population of Catalonia. Reference data comes from the project. GCAT (Genomes for Life) from the Germans Trias i Pujol Research Institute (IGTP).
Reference
Saucy A, Espinosa A, Iraola-Guzman S, Castaño-Vinyals G, Harding BN, Karachaliou M, Ranzani I, De Cid R, García-Aymerich J, Kogevinas M. Environmental exposures and long COVID in a prospective population-based study in Catalonia (COVICAT study). Environmental health perspectives. 2024. https://doi.org/10.1289/EHP15377
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