Extended Exposure to Air Pollution Raises Hospitalization Risk in COVID-19 Patients with Pre-existing Respiratory Diseases

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Patients with asthma or chronic obstructive pulmonary disease (COPD) who live in areas with high levels of air pollution have an increased risk of hospitalization if they contract COVID-19, according to a new pilot study published online in the journal Respiratory Medicine.

The study is the first to look at an association between air pollution, COVID-19, and individual patients, noted lead author Angelico Mendy, MD, PhD, assistant professor of environmental and public health, at the University of Cincinnati College of Medicine, in a press release.

“Particulate matter is very small, small enough to be inhaled deep into the lungs, they cross into the blood and also affect other organ systems,” said Mendy in the press release. “Air pollution as a result of emissions from automobiles, factories or other sources is a generator of particulate matter.”

Ecological evidence suggests that exposure to particulate matter with a diameter ≤2.5 μm (PM_2.5) may contribute to COVID-19 severity and mortality, but no individual-level study has confirmed this association, wrote Mendy and colleagues.

To further understand this association, researchers identified 1128 patients (median age, 46 years) diagnosed with COVID-19 at the University of Cincinnati health care system. Using medical records to identify patients’ zip codes, researchers estimated PM_2.5 exposure over a 10-year period (2008-2017).

“Our study didn’t find any correlation between severity of COVID-19 and particulate matter in general, but we found something for people who had asthma and COPD,” added Mendy in the press release. “People who have preexisting asthma and COPD, when they are exposed to higher levels of particulate matter, they are more likely to have severe COVID-19, severe enough to be hospitalized.”

The results showed that in COVID-19 patients with asthma or COPD, the odds of hospitalization were approximately 60% higher with a 1-unit increase in PM_2.5. No association was observed, however, among COVID-19 patients without a pre-existing respiratory disease.

In the press release, Mendy noted that he hopes to use these preliminary findings to generate support for a larger comprehensive study of patients.

“Independent replications are needed to confirms these results,” concluded study authors. “If the observed associations are confirmed in future studies and are indeed causal, appropriate measures to prevent SARS-CoV-2 infection particularly in patients with asthma or COPD residing in high PM_2.5 exposure areas could reduce COVID-19 hospitalization and morbidity.”