Exposure to air pollution associated with long-term COVID risk in young adults

Long-term exposure to ambient air pollution was associated with increased risk of long-term COVID among young adults, according to a Swedish population-based cohort study.

≤2.5 µm for each increase in the interquartile range (IQR) of exposure to particulate matter (PM_2.5) 2019 (median annual exposure 6.39 μg/m3³Erik Melén, M.D., Ph.D., of the Karolinska Institutet in Stockholm, and his co-authors report about a 30% increase in the odds of developing long-term COVID-19.

Adjusted odds ratio for PM_2.5 The increase per IQR was 1.28 (95% CI 1.02-1.60) for prolonged COVID, odds ratios were 1.65 (95% CI 1.09-2.50) for dyspnea symptoms and 1.29 (95% CI 1.09-2.50) for olfactory/taste changes. CI 0.97-1.70).Mellen and team Lancet Regional Health – Europe.

The association tended to be stronger in participants with asthma and those who had COVID in 2020 compared to 2021, they added.

“Exposure to ambient air pollution has been shown to be positively associated with increased levels of inflammatory cytokines and proteins, which may be a possible cause of multiple symptoms of the post-COVID-19 condition. proposed,” wrote Melén and the team. “In addition, air pollution has been found to be associated with immune dysregulation, including immunosuppression, and has been reported to be associated with the risk of persistent post-COVID-19 symptoms.”

“The virulence of the SARS-CoV-2 virus could be altered in contaminated areas as a contributing mechanism,” they continued. “In addition, long-term exposure to air pollution can adversely affect a wide range of comorbidities, including cardiometabolic and respiratory diseases, which have been found to be associated with long-term risk of developing COVID. This is consistent with the observed results, where the association tended to be stronger among participants with asthma.”

The authors, PM_2.5 Exposure is often the result of road pollution, ship pollution, industrial processes, or some form of residential heating system.

In this study, particulate matter (PM_Ten), nitrogen oxides (NO_X), and black carbon (BC), but none of these were significantly associated with long-term risk of COVID.

“Little is known about the importance of the timing of exposure to air pollution, for example, early childhood exposure when the lungs may be more susceptible to environmental exposures, or later in life,” Melén said. colleague points out.

“Because air pollution is a modifiable risk factor through national or regional public health regulations and individual interventions, our results suggest that continued efforts to reduce air pollution levels have broad public health implications. It confirms that it brings benefits,” they concluded.

Mellen and team used data from the BAMSE (Swedish abbreviation for Children, Allergy, Environment, Stockholm, Epidemiology) cohort. The participant completed a web questionnaire regarding persistent symptoms after acute SARS-CoV-2 infection from October 2021 to her February 2022.

The median age was 26.5 years and 60.7% were female. Approximately 52% of participants reported being bedridden after infection, whereas only 3.5% of them had been vaccinated prior to infection.

In this study, we defined ‘long-term COVID’ as symptoms after confirmed COVID lasting more than 2 months. The most common symptoms included changes in taste and/or smell (10.6% of his patients), dyspnea (4.8%), and fatigue (4.5%).

Air pollution levels at individual-level addresses were estimated using distributed modeling.

The authors attributed this to the observational nature, potential errors in reporting COVID self-diagnosis, misclassification of exposure levels to air pollution, variability in patient vaccination status, and inability to exclude all confounding factors. We acknowledged that the study had some limitations.