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December 04, 2024
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Exposure to air pollutants may increase the persistent, long COVID risk

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Key takeaways:

  • Exposure to particulate matter showed a linear association with persistent, long COVID symptoms.
  • However, these results were not statistically significant.

Greater exposure to particulate matter in the air may be linked to longer duration of long COVID symptoms, a population-based cohort analysis published in Environmental Health Perspectives showed.

The findings build upon previous literature on environmental pollutants, COVID-19 and long COVID, with the risk of long COVID remaining significant even after declining rates during the pandemic.

Air pollution such as fine particulate matter may increase the risk for dementia. Image: Adobe Stock
Exposure to particulate matter showed a linear association with persistent, long COVID symptoms. Image: Adobe Stock

“We previously found that air pollution exposure is linked to a higher risk of severe COVID-19 and a lower vaccine response, but there are very few studies on long COVID and the environment,” Manolis Kogevinas, PHD, a research professor at ISGlobal and the senior author of the study, said in a press release.

In the analysis, Kogevinas and colleagues determined the effects of several environmental exposures, including particulate matter (PM2.5 and PM10), traffic noise at night, green spaces and artificial light at night, on long COVID risk and its persistence.

The study examined these effects within a sample of 2,853 adults, aged 40 to 65 years, taken from the Spain-based COVICAT epidemiological study.

All participants reported at least one SARS-CoV-2 infection between 2020 and 2023 and completed online surveys — used for collecting data on infections, vaccination and sociodemographics — in 2020, 2021 and 2023.

Among the participants, 24% had long COVID symptoms that lasted 3 months or more and 5% had persistent, long COVID symptoms that lasted 2 years or longer.

Long COVID occurred more frequently in women vs. men (27.6% vs. 19.4%), in those with lower education vs. a college education (29.2% vs. 22.2%), in those with prior chronic diseases vs. those without (33.3% vs. 19.7%) and those with severe COVID-19 vs. mild to moderate COVID-19 (71.8% vs. 25.1%).

Additionally, results showed lower long COVID prevalence among vaccinated study participants prior to their first infection compared with unvaccinated individuals (15.4% vs. 46%).

The researchers found a linear relationship between exposure to PM2.5 (RR = 1.14; 95% CI, 0.96-1.36) and PM10 (RR = 1.15; 95% CI, 0.96-1.39) and persistent long COVID compared with those without long COVID.

However, they reported that these associations did not achieve statistical significance.

Other environmental factors studied showed no links to long COVID symptoms.

Kogevinas and colleagues explained that air pollution may increase persistent, long COVID risk by increasing the severity of the initial SARS-CoV-2 infection.

“This hypothesis is supported by the association between particulate matter and the most severe and persistent cases of long COVID, but not with all cases of long COVID,” Apolline Saucy, PhD, a postdoctoral researcher at the Institute of Social and Preventive Medicine and lead author of the study, said in the release.

The researchers added that further research on long COVID symptoms and subtypes “could offer more detailed understanding of the observed associations.”

Ultimately, “this type of [study] is particularly relevant as more people continue to recover from COVID-19 and deal with its potential long-term effects,” Kogevinas said.

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