TOXIC AIR ‘TO BLAME FOR 60,000 CASES OF DEMENTIA’
Diesel fumes a major cause, warn experts
AIR pollution could be responsible for 60,000 cases of dementia in the UK, a major study suggests.
Scientists found that people living in areas polluted by traffic and industry are 40 per cent more likely to develop dementia.
They are particularly concerned by nitrogen dioxide and sooty smog belched out by old diesel cars. The findings provide the strongest evidence so far that toxic fumes are linked to Alzheimer’s disease and other forms of dementia.
One in 14 cases of dementia may be caused by air pollution, researchers from King’s College London and St George’s, University of London, calculated. Some 850,000 people in the UK have dementia, and the number is expected to soar to 1 million by 2025 and 2 million by 2050.
The disease is thought to be largely caused by genetics, with smoking, obesity and lack of exercise increasing the risk. But the study suggests
air pollution also plays a major role. More than 40,000 people in the UK are thought to die early every year because of air pollution.
Earlier this week, scientists revealed they had found tiny particles of vehicle soot in the wombs of pregnant women, suggesting even unborn babies are at risk.
The lead author of the new research, Professor Frank Kelly, calculated 7 per cent of cases of dementia could be attributed to air pollution. If applied to the 850,000 cases in the UK, his figures suggest 60,000 cases could be prevented if air pollution was eradicated.
Professor Kelly, of King’s College London and a Whitehall adviser on air pollution, said: ‘This is a very serious problem. The more we look at all the chronic diseases in society, the more air pollution crops up as a recurring factor.
‘We’re not saying air pollution is the only cause of dementia. But by tackling air pollution, even if you merely delayed the onset of dementia, that would be of enormous benefit for families and the health service.’
The research team, whose findings were published in the BMJ Open medical journal last night, tracked 131,000 people aged 50 to 79 living within Greater London, and followed them for seven years.
Using participants’ postcodes, they looked at air pollution data and compared it to their health records. They found people living in the most polluted areas were far more likely to develop dementia.
Those living in areas with the highest 20 per cent of nitrogen dioxide emissions had a 40 per cent increased dementia risk. Diesel cars – particularly the older models – produce far more nitrogen dioxide than petrol vehicles.
The scientists also found that people with the highest 20 per cent exposure to microscopic sooty particles – also linked to diesel – had a 26 per cent increased risk of dementia.
Professor Kelly, who chairs the Department of Health’s committee on the medical effects of air pollution, said: ‘On the road, older diesel vehicles are by far the most polluting. It’s not just cars – it’s the buses and the taxis.’
Although the study focused only on people living within the M25, experts are convinced it is representative of the whole country.
The UK is notoriously bad at controlling air pollution, with 37 cities persistently displaying illegal levels and the Government repeatedly being hauled into court over the past few years.
Simon Alcock, of environmental law firm ClientEarth, said: ‘Air pollution is damaging our health from the womb to old age. It is unacceptable in 2018 for people to be risking dementia just by breathing. We need big, bold action from the Government to clean up the air and protect our health.’
The microscopic particles in air pollution are breathed deep into the lungs and enter the bloodstream. Scientists believe they then travel into the brain where they provoke inflammation – a problem which may trigger dementia. Diesel cars have been promoted since the 1970s as an environmentally-friendly choice because they emit less carbon dioxide. Tony Blair’s Labour government, in particular, used generous tax breaks to persuade drivers to buy diesel cars.
The tactic contributed to the number of diesel drivers jumping from 1.5 million in 2006 to more than 12 million today.
But in recent years scientists have realised that diesel also produces more of the tiny particles and nitrogen oxides that are damaging to our health.
Aaron Kiely, of Friends of the Earth, said: ‘ Road traffic is the major cause of the UK’s air pollution crisis – as well as being a significant contributor to climate change. Efforts to clean up our cars, vans and lorries must be put in the fast lane – we can’t afford to wait until 2040 for most new vehicles to be zero-emission.
‘ Greater investment is also needed in alternatives to motor vehicles, such as safer cycling infrastructure, and affordable and convenient public transport.’
But Dr James Pickett, of the Alzheimer’s Society, pointed out that the research had looked only at the chance of developing dementia, and had not actually proved that the pollution had caused the illness. ‘There is evidence that exposure to air pollution can cause small particles to enter the brain, but it’s a huge leap to say that air pollution could lead to dementia and this study had several limitations,’ he said.
A spokesman for the Department for Environment, Food and Rural Affairs said: ‘Air pollution is the top environmental risk to human health in the UK, and while air quality has improved significantly since 2010, we recognise there is more to do.
‘This is why we have put in place a £3.5 billion plan to reduce harmful emissions from road transport and have an ambitious Clean Air Strategy which has been commended by the World Health Organisation.’
‘Damaging from womb to old age’