[Note from BenIndy Contributor Nathalie Christian: Air pollution and climate change’s impact on public health is so much varied and vast than a lot of people realize. Self included.]

Global study suggests connection has been strengthened over time across every country and continent.

The Guardian, by Andrew Gregory, August 7, 2023

Air pollution is helping to drive a rise in antibiotic resistance that poses a significant threat to human health worldwide, a global study suggests.

The analysis, using data from more than 100 countries spanning nearly two decades, indicates that increased air pollution is linked with rising antibiotic resistance across every country and continent.

It also suggests the link between the two has strengthened over time, with increases in air pollution levels coinciding with larger rises in antibiotic resistance.

“Our analysis presents strong evidence that increasing levels of air pollution are associated with increased risk of antibiotic resistance,” researchers from China and the UK wrote. “This analysis is the first to show how air pollution affects antibiotic resistance globally.” Their findings are published in the Lancet Planetary Health journal.

Antibiotic resistance is one of the fastest-growing threats to global health. It can affect people of any age in any country and is already killing 1.3 million people a year, according to estimates.

The main drivers are still the misuse and overuse of antibiotics, which are used to treat infections. But the study suggests the problem is being worsened by rising levels of air pollution.

The study did not look at the science of why the two might be linked. Evidence suggests that particulate matter PM2.5 can contain antibiotic-resistant bacteria and resistance genes, which may be transferred between environments and inhaled directly by humans, the authors said.

Air pollution is already the single largest environmental risk to public health. Long-term exposure to air pollution is associated with chronic conditions such as heart disease, asthma and lung cancer, reducing life expectancy.

Short-term exposure to high pollution levels can cause coughing, wheezing and asthma attacks, and is leading to increased hospital and GP attendances worldwide.

Curbing air pollution could help reduce antibiotic resistance, according to the study, the first in-depth global analysis of possible links between the two. It also said that controlling air pollution could greatly reduce deaths and economic costs stemming from antibiotic-resistant infections.

The lead author, Prof Hong Chen of Zhejiang University in China, said: “Antibiotic resistance and air pollution are each in their own right among the greatest threats to global health.

“Until now, we didn’t have a clear picture of the possible links between the two, but this work suggests the benefits of controlling air pollution could be twofold: not only will it reduce the harmful effects of poor air quality, it could also play a major role in combatting the rise and spread of antibiotic-resistant bacteria.”

Although air is recognised as being a direct pathway for disseminating antibiotic resistance, there is limited data on the different pathways that antibiotic resistant genes are carried via air pollution.

Potential pathways include hospitals, farms and sewage-treatment facilities that emit and spread antibiotic-resistant particles through the air and then across wide distances.

Until now, there was limited data on how much influence PM2.5 air pollution – which is made up of particles 30 times smaller than the width of a human hair – has on antibiotic resistance globally.

Sources of PM2.5 include road traffic, industrial processes and domestic coal and wood burning. Data indicates 7.3 billion people globally are directly exposed to unsafe average annual PM2.5 levels.

The authors created an extensive dataset to explore whether PM2.5 was a key factor driving global antibiotic resistance, using data for 116 countries from 2000 to 2018. The data sources included the World Health Organization, European Environment Agency and the World Bank.

The findings indicate antibiotic resistance increases with PM2.5, with every 10% rise in air pollution linked with increases in antibiotic resistance of 1.1%.  

The association has strengthened over time, with changes in PM2.5 levels leading to larger increases in antibiotic resistance in more recent years. The analysis indicates antibiotic resistance resulting from air pollution was linked to an estimated 480,000 premature deaths in 2018.

A modelling of possible future scenarios indicates that if there were no changes to current policies on air pollution, by 2050 levels of antibiotic resistance worldwide could increase by 17%. The annual premature death toll linked to antibiotic resistance could rise to about 840,000. [Emph. added by BenIndy Contributor.]

The authors acknowledged limitations to their study. A lack of data in some countries may have affected the overall analysis, they said.

The study was observational, so could not prove cause and effect. Future research should focus on investigating the underlying mechanism of how air pollution affects antibiotic resistance, they said.

A second study published in the journal BMJ Mental Health found that exposure to relatively high levels of air pollution was associated with increased use of community mental health services by people with dementia. The long-term study focused on a large area of London with heavy traffic.