UK Edition
Power lines, air pollution and lack of sunshine may raise risk of dementia, warns University of Edinburgh
Power lines, air pollution and too much time spent indoors may all raise the risk of dementia, according to experts at the University of Edinburgh.
Scientists believe that around two thirds of the risk of dementia is caused by the lifestyle factors such as smoking, diabetes, obesity, as well as genetics.
Yet one third of the risk is still unexplained and Edinburgh researchers believe that some environmental factors could be to blame.
They looked back over more than 4,000 studies to draw up a shortlist of the most likely culprits.
They found that a lack of vitamin D – produced by the body through exposure to sunlight – and exposure to air pollution were strongly implicated, along with occupational exposure to some types of pesticide.
Excessive levels of minerals found in drinking water, such as selenium, may also be linked to the disease, according to the research, as well as living under power lines.
Air pollution has been found to raise the risk of cardiovascular disease so it may also cause oxidative stress or inflammation in the brain, the researchers speculate. Tiny magnetic particles of materials produced by car engines and brakes have also recently been found in the brains of Alzheimer’s sufferers.
Public Health England is so concerned that Britons are not getting enough vitamin D that they recently encouraged everyone to take a supplement in the winter months. The vitamin is important for a healthy immune system and helps clear amyloid plaques from the brain which are a hallmark of Alzheimer’s disease.
Dr Tom Russ, of the Alzheimer Scotland Dementia Research Centre at the University of Edinburgh, said: “Our ultimate goal is to prevent or delay the onset of dementia. Environmental risk factors are an important new area to consider here, particularly since we might be able to do something about them.
“We found that the evidence is particularly strong for air pollution and vitamin D deficiency. But we really need more research to find out whether these factors are actually causing dementia and how, and if so, what we can do to prevent this.”
Around 600,000 people in Britain suffer from dementia, the majority of which is Alzheimer’s disease, costing the country more than £26 billion annually.
But doctors and scientists believe that a significant proportion of cases could be prevented or delayed by addressing environmental and lifestyle factors linked to the disease.
The team behind the latest research says future studies should focus on the short list of environmental risk factors flagged up in their study.
Prof Tom Dening, Professor of Dementia Research at the University of Nottingham, said: “It is a fascinating study and a well conducted review.
“What is difficult is to tell whether the environmental exposures are themselves contributing to dementia or whether they are in fact acting as proxies for some underlying variable. For instance, many unpleasant environmental exposures (traffic fumes, living near power lines, poor water quality) are related to socio-economic deprivation, which itself is related to poor diet, low education, higher stress and worse health.
“So we really cannot easily tell what is causing what.”
Jim Pearson, Director of Policy and Researcher at Alzheimer Scotland, added: “The research study substantially improves our knowledge and understanding of environmental factors which may increase the risk of developing dementia and provides a basis for further, and more focussed, research in this area.”
Dr Tara Spires-Jones, Interim Director of the Centre for Cognitive and Neural Systems at the University of Edinburgh, said: “While the current paper is informative to scientists studying factors that cause dementia, more work needs to be done to establish causal relationships.”
The research, published in the journal BMC Geriatrics.