As the death toll from the coronavirus pandemic approaches the grim milestone 6 mio, researchers are still trying to determine why some people have more severe infection outcomes than others. Apart from age, health and other individual factors, an early variable has been the presence of air pollution, specifically particles with a diameter of 2.5 micrometers or less (PM2.5). In April 2020, researchers from Harvard University found that small increases in particles can produce large effects in mortality. A recent study from Italy has taken a closer look at what happened to the inhabitants of a city from the beginning of the pandemic to March 2021.
Low level exposure risk
Which has been growing evidence that air pollution may increase the risk of serious COVID-19 disease. For example, in 2020, researchers found that increased exposure to such dangerous air pollutants as formaldehyde is associated with a 9% increase in deaths among people with COVID-19. Another 2020 examination by researchers in Europe and the United States estimated that particulate air pollution contributed about 15% to worldwide COVID-19 mortality.
Published in Occupational and environmental medicinethe recent Italian prospect examination looked at Varese, a municipality near the Swiss border that is the eighth largest city in Lombardy. Northern Italy has air pockets where pollution exceeds limits set by the EU, so researchers wanted to see how these levels affected residents over a period of about 1 year.
The researchers were motivated to carry out the study because most of the previous studies had fewer granular data – information at county, provincial or state level. They were also limited to the first half of 2020.
“In our analyzes, we were able to take into account most of the demographic and clinical characteristics that may increase SARS-CoV-2 susceptibility apart from prolonged exposure to airborne pollutants,” said the corresponding author. Giovanni Veronesi, Professor at the Research Center of Epidemiology and Preventive Medicine, Department of Medicine and Surgery, at the University of Insubria in Italy. “In addition, we offer a range of sensitivity analyzes, some based on the careful peer review process, to strengthen confidence in our results. We believe we have provided the first solid empirical evidence for the link between prolonged exposure to air pollution and the occurrence of COVID-19. “
Veronesi and his colleagues collaborated with universities, regional health institutions and Arianet, an environmental consulting firm, to track 62,848 people aged 18 or older in Varese. Based on their addresses and air quality measurements, these residents were associated with exposure to pollutants, including PM2.5. There were 4,408 cases of coronavirus infection during the period and an annual average of PM2.5 at 12.5 micrograms per cubic meter. The study found a further 294 cases per. 100,000 people per year and concluded that “an increase in exposure to long-term airborne pollutants of 1[microgram per cubic meter]is associated with a 2-5% increase in the incidence of COVID-19. “Sensitivity analyzes confirmed the association, according to the study.
Veronesi said he was surprised to find that there was an increased COVID-19 risk, even with relatively low concentrations of PM2.5.
“This agrees really well with the idea that continuous exposure to even low levels of air pollution makes people more susceptible to disease – and it reinforces the need for deep [social] changes to have a healthier life, ”Veronesi said.
Possible endemic threat
Heather Waltonan associate professor of environmental health at Imperial College London, who was not involved in the study, said that although the statistical analysis needs to be confirmed, the results add to the existing knowledge.
“There are only a few studies that have individual data available. There have already been other studies on long-term exposure to air pollution and hospitalizations that had individual data, but at least until May 2021… there was no such study on the incidence of infection. This however, depends on whether the statistical analysis is appropriate, “said Walton, co-author of an Imperial College review on pollutants and COVID-19. ‘The hypotheses treated are well known. Nevertheless, if the statistics check out, then it is good to have further evidence on the hypotheses. “
Veronesi noted that more research is needed to establish a causal link between air pollution and COVID-19 susceptibility. He and his collaborators are working to expand the study to cover more people, a longer period, non-urban environments and broader COVID-19 endpoints, such as hospitalizations and deaths.
“If SARS-CoV-2 is to become endemic in a population, our results suggest that this will be an additional health threat to people already suffering from higher respiratory and cardiovascular diseases due to exposure to air pollution,” Veronesi said. “Therefore, governments should implement their efforts to reduce air pollution levels as a measure to mitigate the public health burden of COVID-19 without further delay.”
—Tim Hornyak (@robotopia), Science Author