Second-hand smoke ‘can increase the risk of dementia’
Inhaling second-hand smoke could increase the risk of developing dementia, a new study suggests.
By Kate Devlin, Medical Correspondent
Last Updated: 7:44AM GMT 13 Feb 2009
Studies have suggested that there is a link between smoking and the development of dementia Photo: GETTY
Scientists found that non-smokers who were exposed to high levels of cigarette smoke were more likely to suffer the early memory problems that could be a sign of the neurological condition.
Previous studies have suggested that there is a link between smoking and the development of dementia.
But the new study is the first to show that adults could be at risk by taking in the smoke of others.
Researchers believe that the connection could be heart disease, a known risk factor for dementia and which can be triggered by smoking.
The new study tested the saliva of almost 5,000 non-smokers, all over the age of 50, for a chemical called cotinine, a by-product of nicotine which can stay in the body for almost two days after inhaling second-hand smoke.
The volunteers were then asked to sit a series of tests designed to assess their level of recall and other skills.
The findings, published in the British Medical Journal, show that those with a high level of the chemical in their bodies were 44 per cent more likely to develop early memory problems, which can be a warning sign for dementia, than those with low levels.
Dr David Llewellyn, from the University of Cambridge, who led the research, said: “Our results suggest that inhaling other people’s smoke may damage the brain, impair cognitive functions such as memory, and make dementia more likely.
“Given that passive smoking is also linked to other serious health problems such as heart disease and stroke, smokers should avoid lighting up near non-smokers.
“Our findings also support calls to ban smoking in public places.”
More than 700,000 people in Britain have dementia, of which more than 400,000 suffer from Alzheimer’s, the most common form.
Experts estimate that the number of sufferers will mushroom sharply in coming decades, mainly because of an increasingly ageing population.