Long-term air pollution exposure linked to Covid-19 incidence

A study of residents in the Italian city of Varese backs up previous research linking air pollution to the risk of Covid-19 infection.

New findings have been released by the Research Center in Epidemiology and Preventive Medicine at the University of Insubria, northern Italy, which shows long-term exposure to air pollution may heighten the chances of contracting Covid-19.

Around 62,000 people were included in the study, with home addresses used to estimate historic exposure to harmful materials in the atmosphere. A link was identified between those who live in areas that have persistently high levels of pollution and their risk of becoming infected. For every microgram rise in pollutants, a 5% increase in infection risk has been identified. Older age groups were more susceptible, with the biggest impact observed among those aged 55 and above. 

A number of factors that could influence findings were taken into consideration, although several key aspects could not be accounted for. These include mobility, weather (humidity and temperature), and underlying health conditions. Further design flaws were evident in the data capture period, which ran to mid-2020, although those involved believe there is enough to determine genuine cause and effect. 

‘From a mechanistic point of view, air pollution has a well-recognised role in prolonged inflammation and downregulation of the immune system,’ a spokesperson for the study wrote in the journal, Occupational & Environmental Medicine. ‘Government efforts to further reduce air pollution levels can help to mitigate the public health burden of Covid-19.’

Researchers have confirmed more work is required to determine whether air pollution directly causes higher Covid-19 infection levels, or if the two are merely correlated. However, the investigation backs up previous reports that found a potential relationship. Last year, the Barcelona Institute of Global Health conducted its own observation of more than 9,000 participants, and also found a possible link. In September, separate work by Imperial College London delivered similar results. 

Photo credit: Martin Sanchez