ULEZ: Sadiq Khan says study linking pollution with dementia ‘further evidence’ clean-air schemes needed

A new King’s College study further highlights the need to clean up London’s air, the mayor has said, after researchers found higher levels of pollution increase the chances someone with dementia will require mental health services.

The study, which was led by academics at the Institute of Psychiatry, Psychology and Neuroscience and ESRC Centre for Society and Mental Health at King’s College, and was published in the BMJ Mental Health journal, analysed data on more than 5,000 people with dementia for up to nine years.

The academics linked levels of nitrogen dioxide (NO2) and particulate matter (PM2.5 and PM10) with anonymised mental health records of community mental health service use.

Air quality models were used to estimate exposure to pollutants in Southwark, Lambeth, Lewisham and Croydon.

According to the study, those living at addresses with exposure to higher levels of PM2.5 and NO2 were likely to record greater use of community mental health services, for reasons ranging from depression to psychosis and behavioural problems linked with dementia.

A spokesperson for the mayor, Sadiq Khan, said the report provides “further evidence” of the need to clean up London’s air, “including rolling out electric charging points, reducing traffic outside schools at pick-up and drop-off times, transforming the capital’s buses and taxis and expanding the Ultra Low Emission Zone (ULEZ)”.

Specifically, the study found those exposed to the highest level of NO2 were 27% more likely to use these services than those exposed to the lowest levels.

PM2.5 appeared to have an even bigger impact, with the highest exposure level making people 33% more likely to use the mental health services.

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 NO2exposure 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.”

The mayor’s spokesperson said: “Sadiq has always been clear that is not prepared to stand by while around 4,000 Londoners die prematurely each year due to air pollution, children are growing up with stunted lungs and thousands of people in our city are developing life-changing illnesses, such as cancer, lung disease, dementia and asthma.

“While 9 in 10 cars seen driving in outer London on an average day meet the ULEZ standards, Sadiq is doing all he can to support Londoners with the switch to cleaner vehicles, including his recent announcement that all Londoners with a non-compliant car will be eligible for the scrappage scheme.

“He also continues to call on government to fund a targeted national scrappage scheme or provide additional funding to London as it has done for other cities implementing Clean Air Zones, including Birmingham, Bristol and Portsmouth.”

City Hall data from earlier this year found every London borough is exceeding the World Health Organisation guidelines for NO2.

Mr Khan described it at the time as “more shocking proof” the capital’s air needs to be cleaned up via schemes such as the ULEZ.