Two medical studies highlight new impacts of air pollution

Global analysis  published in the Lancet has suggested a link between air pollution and antibiotic resistance, just days after research published in the British Medical Journal pointed at a connection between the higher use of health services by dementia sufferers in areas of higher air pollution.

The former research was undertaken by Zhejiang University who observed that ‘Antibiotic resistance is an increasing global issue, causing millions of deaths worldwide every year.’

They examined levels of air pollution and levels of antibiotic resistance in 166 countries and detected a correlation between high levels of PM2.5 air pollution and high levels of antibiotic resistance that became even stronger over time. As the levels of particle pollution rose, so did levels of antibiotic resistance.

The study found high levels of antibiotic resistance in north Africa, the Middle East, and south Asia, whereas Europe and North America had low antibiotic-resistance levels.

The researchers estimate that a 10% increase in annual PM_2·5 could lead to a 1·1% increase in antibiotic resistance resulting in 43,654 premature deaths.

Hong Chen, an author of the new study  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 combating the rise and spread of antibiotic-resistant bacteria.’

In the research published in BMJ Mental Health, a team from the Institute of Psychiatry, Psychology and Neuroscience at King’s College London examined associations between air pollution exposure and mental health service use in people with dementia.

The research group, led by academics at the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) and ESRC Centre for Society and Mental Health at King’s College London, analysed data on 5,024 people with a primary diagnosis of dementia for up to nine years. They used a state-of-the-art air quality model to estimate address-level exposure to pollutants in Southwark, Lambeth, Lewisham, and Croydon.

Associations between air pollution and the use of Community Mental Health Team (CMHT) events over a nine year period were examined. More than half of those involved had Alzheimer’s disease (5%), 20% had vascular dementia, and 26.5% had unspecified dementia.

It was seen that dementia sufferers in areas with the highest level of exposure to NO₂ were 27 per cent more likely to use these services compared with those living in areas with the lowest levels of exposure to NO₂. Those exposed to the highest level of very small particulate matter (PM_2.5) were 33 per cent more likely to use community mental health services. These associations were still evident five and nine years later.

Dr Amy Ronaldson, Research Fellow at King’s IoPPN, and first author, said: ‘Our study showed that there were stronger associations for patients with vascular dementia, which is caused by reduced blood flow to the brain, and implies that air pollution might impact the development of vascular dementia more than other dementia types.

‘We looked at associations between air pollution and cognitive function over time, as well as physical health and social functioning. The results of the study indicate that NO₂ exposure negatively impacts health and social functioning more so than cognitive function, which might partially explain how air pollution leads to more use of community mental health teams in people with dementia.’