Researchers at King’s College London have found that exposure to air pollution is associated with an increase in use of mental health services by people with dementia.
Over the past year, the evidence has been building around the link between air pollution and an increased risk of developing dementia. But little is known about how exposure to the most common forms of air pollution – nitrogen dioxide (NO2) and particulate matter – can impact people already living with the condition. Now, this new research suggests a knock-on effect of air pollution on already over-stretched health services and the lives of people living with dementia.
The researchers, funded by mental health charity MQ and others, looked at community mental health service use over nine years by over 5,000 people aged 65 and over. All participants lived in four boroughs of south London – Croydon, Lambeth, Lewisham or Southwark – following their initial dementia diagnosis between 2008 and 2012.
The study, published in medical journal BMJ Mental Health, measured cognitive function and health and social functioning at three points in time – up to 12 months after diagnosis, up to five years after diagnosis, and up to nine years after diagnosis. They then looked at quarterly published estimates for NO2 and particulate matter – covering the areas around the participants’ homes during the same timeframe.
“As you increase the dose of air pollution, the likelihood of using community mental health teams increased as well,” lead author Dr Amy Ronaldson, research fellow at the Institute of Psychiatry, Psychology and Neuroscience at King’s College London, told the i newspaper.
Those in areas with higher levels of NO2 were 27% more likely to use community mental health services than those living in areas with the lowest levels, while those exposed to the highest levels of particulate matters were 33% more likely to use them. The effects appeared stronger for people vascular dementia than other forms of dementia.
The results suggested air pollution might be having its effect through its impact on physical health – and therefore daily activities – of people with dementia, and could therefore be detrimental to their mental health, Dr Ronaldson added.
Due to the observational nature of this study, the researchers said that “no firm conclusions” could be drawn about cause and effect. However, they suggested that if the annual level of exposure to particulate matter in London was reduced, as recommended by Alzheimer’s Research UK and The World Health Organisation, the number of community mental health service contacts made by people with dementia could fall by 13%.
Dr Susan Mitchell, Head of Policy at Alzheimer’s Research UK, said the Government “can’t continue to turn a blind eye to air pollution” and that its proposed changes could be “a decade too late”.
She added: “As well as urgent action to bring levels down, there is a pressing need to find out more about exactly how air pollution affects dementia risk. This evidence will allow Government and policymakers to develop policies that can reduce the impact of air pollution exposure on people at risk of developing dementia, and those living with the condition.”