Air pollution a ‘likely’ cause of dementia

Landmark report shows toxic emissions speed up mental decline

AIR pollution is likely to cause dementia, a committee of government advisers said yesterday.

Issuing a landmark report, the panel concluded there was finally enough evidence to show a clear link with brain damage.

Toxic emissions were already considered a risk to the heart and lungs, cutting short the lives of an estimated 40,000 Britons a year.

But the report is the first official recognition that air pollution causes mental decline as well.

Dementia blights the lives of 850,000 people in the UK, a figure expected to hit a million by 2025 and two million by 2050. Last year it was the second leading cause of death after Covid.

The bombshell findings will put renewed pressure on ministers to clean up Britain’s filthy air.

A summary of the report states: ‘We have reviewed nearly 70 studies in human populations which have examined the possible link between air pollutants and effects on mental ability and dementia. We think it is likely

that air pollution can contribute to a decline in mental ability and dementia in older people. It is known that air pollution, particularly small particle pollution, can affect the heart and the circulatory system, including circulation to the brain.

‘These effects are linked to a form of dementia (vascular dementia) caused by damage to the blood vessels in the brain.

‘Therefore, we think it likely that air pollution contributes to mental decline and dementia caused by effects on the blood vessels.’

The expert panel – the Committee on the Medical Effects of Air Pollutants – did not estimate how many cases of dementia in older people were linked to air pollution. But Frank Kelly, the Imperial College London professor who chaired the group, pointed to a 2018 London study indicating roughly 60,000 of the 209,600 new cases of dementia in the UK each year could be due to poor air quality.

One theory is that particulates in air pollution – tiny particles of soot around a fortieth the width of a human hair – damage blood vessels, harming the brain’s blood supply. Other possible mechanisms by which pollution harms the brain are that fine particulates could enter the brain directly via the nasal nerves, or trigger an immune response.

The report states: ‘There is evidence that air pollution, particularly particulate air pollution, increases the risk of cardiovascular, including cerebrovascular, disease. These diseases are known to have adverse effects on cognitive function. It is therefore our view that there is likely to be a causal association between particulate air pollution and effects on cognitive function in older people.’

The report acknowledges that more evidence is needed to determine whether air pollution can have an effect on brain function and health at the concentration levels being recorded in the UK.

Brian Castellani, a Durham University expert who was not involved in the report, said: ‘Thanks to an immense amount of work in the last several years, we can say with confidence this link exists.’

Gavin Thompson of Friends of the Earth said the report was further evidence that air pollution was devastating for human health. He added: ‘We have known for a long time that traffic fumes cause asthma and heart conditions, and evidence has been growing about the risk that tiny particles – from exhaust fumes, tyres and brakes – pose to our cognitive health.’

In March, the Department for Environment, Food and Rural Affairs laid out legally-binding targets to protect air, water and nature. But campaigners said the levels allowed for fine particle pollution by 2040 were far too high.