Many say dementia is a scarier prospect than cancer. But there may be new ways to reduce the risk of dementia, hints the first comprehensive review of the influence of environment on its incidence.
The causes of dementia are not completely understood. Around a third of an individual鈥檚 risk seems to be down to their genes, while health factors like weight, exercise and cardiovascular health account for about 20 per cent.
The remainder is something of a mystery. Our environment probably has a role to play, says at the University of Edinburgh, UK.
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Looking at 60 past studies, Russ鈥檚 team found plenty of evidence that air pollution is associated with dementia. 鈥淭here weren鈥檛 any studies that didn鈥檛 find a link between air pollution and dementia,鈥� says Russ. 鈥淧articulate matter, nitric oxides, ozone or carbon monoxide 鈥� all were linked to dementia.鈥�
There was also a clear link with vitamin D deficiency, and a weaker association with passive smoking and occupational exposure to pesticides.
More surprising was the link between dementia and living close to power lines. 鈥淭here鈥檚 not a lot of evidence, but what there is seems to be reasonably robust,鈥� says Russ. 鈥淚t鈥檚 a small association, and I鈥檓 not sure what the mechanism would be.鈥�
Russ says it would be premature to advise people to limit their exposure to any of these things. Although some studies provide strong evidence of correlations, the team cannot definitively conclude that any of these factors cause dementia. It will be down to governments and public health agencies to control things like air pollution, says Russ.
People hoping to reduce their own chances of getting dementia should follow existing advice, which recommends limiting the risk by eating healthily, getting plenty of exercise and not smoking.
BMC Geriatrics
