A new research has found that people recently exposed to dirtier air before contracting the illness spent four days longer in hospital, the same impact as on those 10 years their senior.
The Belgian study also showed that air pollution levels measured in patients’ blood were linked to a 36% increase in the risk of needing intensive care treatment. A separate study in Denmark showed air pollution exposure was linked to a 23% increase in the risk of death from Covid-19. In both studies, the level of air pollution was below legal EU standards.
Previous research had suggested that air pollution worsened Covid outcomes but, rather than assessing groups of people together, the new studies followed individual patients and therefore give much more confidence in the results.
Known to be a major risk factor in aggravating respiratory diseases, air pollution also increases inflammation in the lungs and weakens immune defences, and causes pre-existing lung problems that worsen the outcomes of new infections.
Among other things, the new research shows that cutting air pollution is a crucial measure for reducing illness and deaths during future outbreaks of respiratory diseases, including the annual flu season. Cleaner air brought health benefits almost as great as some of the medical treatments given to the Covid-19 patients, the research showed.
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“Reducing air pollution, even when at relatively low levels, increases the health of the population and makes them less susceptible to future pandemics,” said Prof Tim Nawrot, at Hasselt University in Belgium. “The pandemic placed an enormous strain on doctors, nurses and other healthcare workers. Our research suggests that air pollution made that burden even greater.”
In his reaction, Dr Zorana Jovanovic Andersen, at the University of Copenhagen, Denmark, and senior author of the Danish study, said: “These results show how air pollution can compromise our immune system and leave us vulnerable. Reduction of air pollution should be at the heart of preventive measures for current and future pandemics, as well as a strategy for dealing with seasonal influenza pandemics.”
Many previous studies assessing the link between Covid and air pollution were what epidemiologists call “ecological studies”, which assess the relationship using averaged data for a whole population. These could be completed quickly and some factors that may influence the link could be taken into account.
However, hidden factors could not be ruled out and the variation of air pollution over short distances could not be accounted for. In contrast, the new studies followed the illness and air pollution exposure in individual people.
Story was adapted from the Guardian.
