Researchers found a correlation between living in an area of high air pollution and use of mental health services among dementia patients
“As you increase the dose of air pollution, the likelihood of using community mental health teams increased as well." Dr Amy Ronaldson, research fellow, King’s College London
People with dementia who live in areas with high air pollution are more likely to access psychiatric services, research has shown.
Researchers at the Institute of Psychiatry, Psychology and Neuroscience at King’s College London analysed data from 5,024 people who have had dementia for nine years. They used air-quality modelling to estimate air pollution levels at the patients’ addresses in Southwark, Lambeth, Lewisham and Croydon. The modelling captured a high level of detail, looking at air pollution down to a 20 by 20-metre radius at the participants’ addresses.
More than half of the people in the study (54%), published in BMJ Mental Health, had Alzheimer’s disease, while 20% had vascular dementia, and 26.5% had unspecified dementia.
The study found that people with dementia who lived nearer to higher levels of air pollution needed to use community health services more for conditions like depression, psychosis and behavioural problems such as agitation or apathy.
“As you increase the dose of air pollution, the likelihood of using community mental health teams increased as well,” Dr Amy Ronaldson, research fellow at the institute, told the i newspaper.
Those in areas with higher levels of nitrogen dioxide (NO2) were 27% more likely to use community mental health services than those living in areas with the lowest levels. Those exposed to the highest levels of particulate matters were 33% more likely to use the services.
The study “suggests that air pollution may contribute towards a broad range of mental health problems, affecting a wide spectrum of clinical services, over long periods of time,” Ronaldson said.
She added that it was likely that air pollution was was affecting the physical health – and therefore daily activities – of people with dementia, and as a consequence was having a detrimental effect on their mental health.
People with vascular dementia, which is caused by reduced blood flow to the brain, appeared to be the most affected. Ronaldson said that air pollution can get into people’s bloodstream and circulation, including circulation to the brain.
Dr Ioannis Bakolis, a reader in biostatistics and epidemiology at the institute said that reducing air pollution could ease demand on mental health services. He estimated that demand could drop by 13% if levels of particulate matter exposure in London fell to WHO recommended levels.
Scientists are becoming increasingly concerned about the impact air pollution has on our physical health, particularly in dense urban areas such as London. We now know that there is a link between air pollution and diseases such as asthma, respiratory infections and even lung cancer. It is worrying, though perhaps not surprising, that there is also a correlation between air pollution and mental illness in dementia patients, though more research is needed to establish the exact mechanism by which pollution might be causing poorer mental health. Studies like this demonstrate the importance of measures to reduce pollution in our towns and cities.