Researchers identify key driver behind soaring Alzheimer’s cases… are YOU at risk?
The global air pollution crisis could be fuelling a rise in Alzheimer’s cases, concerning research suggested today.
World Health Organization (WHO) officials have long demanded countries take tougher action to combat the scourge of pollution, which is thought to kill 7million people every year globally.
Studies have previously suggested there may be a link between particles less than 2.5 micrometers in diameter (PM2.5)—considered the most dangerous air pollutant—and cognitive decline.
But in first-of-its-kind research, US scientists who assessed over 600 autopsies of patients who had dementia, found PM2.5 exposure specifically affects the central nervous system and impacts brain function.
For every 1 μg/m3 increase in PM2.5 per year patients were exposed to, they were 17 per cent more likely to see the toxic proteins tau and amyloid spreading in the brain.
Significant clumps of these protein can form plaques and tangles—and this is thought to be behind the symptoms of Alzheimer’s, the leading cause of dementia.
But they did not hypothesise exactly what caused PM2.5 to increase levels of tau and amyloid in the brain.
Writing in the journal JAMA Neurology, the team from the University of Pennsylvania said: ‘This study reinforces the finding that PM2.5 exposure appears to negatively affect cognitive function and suggests that this may be mediated by ADNC.
World Health Organization (WHO) officials have long demanded countries take tougher action to combat the scourge of pollution, which is thought to kill 7million people every year globally
‘Our findings suggest that PM2.5 exposure may exacerbate the development of Alzheimer’s disease.’
Exposure to PM2.5 has been linked to increased risk of a host of deadly diseases, including lung and colon cancer, as well as heart disease.
The particles, emitted by car exhausts and wood-burning stoves, can be so small they are invisible to the naked eye, yet travel deep into the lungs and bloodstream.
In the study, researchers assessed 602 autopsies from between 1999 and 2022 from 11 US states—California, Colorado, Connecticut, Delaware, Maryland, New Jersey, New York, Ohio, Pennsylvania, Virginia, and West Virginia.
They then matched each patient’s address prior to the death with a one year PN2.5 average concentration by assessing latest data and computer models.
‘Exposure to higher levels of PM2.5 was associated with more advanced Alzheimer’s disease neuropathologic change,’ the scientists said.
‘We found that higher PM2.5 concentrations were strongly associated with more severe amyloid and tau pathologies, culminating in more advanced overall Alzheimer disease.’
Specifically, for every 1 μg/m3 increase in 1-year mean PM2.5 exposure, there was a 17 per cent higher risk of more tau and amyloid in the brain.
There was also a 19 per cent increased likelihood of higher levels of Alzheimer’s disease neuropathologic change and a 16 per cent increase in the odds of having a large infarct, a stroke that affects a significant portion of the brain.
The scientists did however acknowledge the study had some limitations, including not considering other potential factors that could have increased their dementia risk.
This included how much exercise they did on average, if they smoked or drank alcohol.
Equally, it did not assess levels of other air pollutants such as nitrogen dioxide or ozone, which together could impact the risk of developing more advanced Alzheimer’s disease.
Other population-based autopsy studies are further needed to generalize these findings,’ they added.
It comes as a landmark study last year suggested almost half of all Alzheimer’s cases could be prevented by tackling 14 lifestyle factors from childhood.
World-leading experts found two new risk factors—high cholesterol and suffering vision loss—were, combined, behind almost one in ten dementia cases globally.
They join 12 existing factors, ranging from genetics to smoking status, that experts have identified as increasing the risk a person would suffer dementia.
Around 900,000 Brits are currently thought to have the memory-robbing disorder. But University College London scientists estimate this will rise to 1.7million within two decades as people live longer. It marks a 40 per cent uptick on the previous forecast in 2017
Experts claimed the study, published in the prestigious journal The Lancet, provided more hope than ‘ever before’ that the memory-robbing disorder that blights the lives of millions can be tackled.
Alzheimer’s Disease is the most common form of dementia and affects 982,000 people in the UK.
Memory problems, thinking and reasoning difficulties and language problems are common early symptoms of the condition, which then worsen over time.
Alzheimer’s Research UK analysis found 74,261 people died from dementia in 2022 compared with 69,178 a year earlier, making it the country’s biggest killer.
However, Alzheimer’s disease is on the rise globally; figures from Frontiers revealed that from 1990 to 2019, new cases of Alzheimer’s and other dementias globally rose by approximately 148 per cent, and total cases increased by around 161 per cent.
This is not just because of air pollution, but reflects the globe’s increasingly large aging population.
