Improving cognitive ability through education and health may cut dementia risk

bjb42 — Fri, 27 Mar 2009 00:00:00 +0000

̽��ֱ��study by Cambridge ̽��ֱ�� researchers Dr David Llewellyn and Dr Fiona Matthews and the Medical Research Council Cognitive Function and Ageing Study shows a small but significant improvement in elderly people's mental abilities over the last two decades which researchers believe could be down to raising the age of compulsory education, reductions in the number of elderly people smoking and other health developments.

Published in the journal Aging, Neuropsychology and Cognition this month, the study could help to predict future numbers of elderly people who will develop dementia with greater accuracy.

̽��ֱ��researchers compared the results of a representative sample of more than 9,000 people over 65 whose mental faculties were tested in 1991 with those of over 5,000 people in 2002. ̽��ֱ��test, an animal naming test which is among the standard ones used for detecting early signs of dementia, was restricted to those whose first language was English and excluded non-white participants and those in nursing homes.

̽��ֱ��researchers also compared the results of 680 East Cambridgeshire residents aged between 60 and 69 who were tested in 1991 with an independent cohort of 600 people tested in 1996.

̽��ֱ��tests showed a small but potentially significant increase in the number of words a minute people used when asked to list words associated with animals. ̽��ֱ��results were similar across the general sample and the East Cambridgeshire sample.

In the 2002 study, the sample was slightly older and more prone to diseases such as hypertension and diabetes mellitus. In both samples, results were lower for older people, women and the less educated. ̽��ֱ��only group which showed no improvement between 1991 and 2002 were the least educated.

Poor cognitive function is associated with the onset of dementia, disability, institutionalisation and death. It has been predicted that around 3.1% of people aged over 60 worldwide will suffer from dementia with significant increases expected as the world's population ages. ̽��ֱ��results of this new study tally with those coming out of the US.

Writing in Aging, Neuropsychology and Cognition, Dr Llewellyn, a research associate in the Department of Public Health and Primary Care, and Dr Matthews, a statistician in the MRC Biostatistics Unit, say: "Our findings are important because detrimental influences on cognitive health appear to have been cancelled out by greater levels of education, fewer heart attacks, increased prescription of antihypertensive medications, decreased smoking and improvements in other unmeasured factors associated with cognition, such as early life nutrition. This is significant as these findings can be used to help refine future projections of cognitive function in aging industrialised populations."

Improvements in education and health could reduce the number of elderly people who suffer from dementia, according to the first study in England to compare elderly cognitive ability.

Our findings are important because detrimental influences on cognitive health appear to have been cancelled out by greater levels of education, fewer heart attacks, increased prescription of antihypertensive medications, decreased smoking and improvements in other unmeasured factors associated with cognition, such as early life nutrition.

Dr Llewellyn & Dr Matthews

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Second-hand smoke linked to cognitive impairment

bjb42 — Thu, 12 Feb 2009 00:00:00 +0000

̽��ֱ��research, published today in the British Medical Journal, highlighted a 44% increase in risk of cognitive impairment when exposed to high levels of second-hand smoke.

Previous studies identified active smoking as a risk factor for cognitive impairment and dementia. However, this is the first large-scale study to conclude that second-hand smoke exposure could lead to dementia and other neurological problems in adults. (Previous findings suggested that second-hand smoke exposure could impair cognitive development in children and adolescents.)

̽��ֱ��research, led by Dr Llewellyn, used saliva samples from nearly 5000 non-smoking adults over the age of 50. By measuring levels of cotinine (a by-product of nicotine) in their saliva and taking a detailed smoking history, the researchers were able to assess levels of exposure to second-hand smoke.

A range of neuropsychological tests were then used to assess aspects of brain function such as verbal memory (recalling words immediately and after a delay), numerical calculations, time orientation, and verbal fluency (naming as many animals as possible in one minute). These results were added together to provide a global score for cognitive function, and those whose scores were in the lowest 10 per cent were subsequently identified as suffering from cognitive impairment.

From their results they concluded that exposure to second-hand smoke may be linked to an increased chance of developing cognitive impairment, including dementia. ̽��ֱ��authors proposed a number of possible explanations for why exposure to second-hand smoke may increase the odds of dementia, including an increased risk of heart disease and stroke which are known to increase the risk of cognitive impairment and dementia.

Dr Llewellyn commented on the research, "We have conducted the first study to examine the association between second-hand smoke exposure and cognitive impairment in elderly non-smokers.

"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."

Exposure to second-hand smoke could increase the risk of developing dementia and other forms of cognitive impairment, according to research published by Dr David Llewellyn from the ̽��ֱ�� of Cambridge and his collaborators.

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.

Dr David Llewellyn

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̽��ֱ�� of Cambridge - David Llewellyn

Improving cognitive ability through education and health may cut dementia risk

Second-hand smoke linked to cognitive impairment