Researchers link smoking to higher risk of developing dementia

Updated June 18, 2007 05:45:00

If there were not already enough health reasons not to smoke, Australian researchers have just come up with another one.

Researchers from the Australian National University (ANU) in Canberra reviewed the link between smoking and cognitive decline found that people who smoke face a much greater risk of developing all kinds of dementia.

The association between smoking and the risk of dementia has been unclear.

Some early studies actually showed that smoking might boost brain performance, while other research suggested the opposite.

Australian researchers wanted to find out just what impact smoking has on your brain function later in life.

Associate Professor Kaarin Anstey from the Centre for Mental Health research at ANU reviewed the link between smoking and dementia in studies done on more than 13,000 people.

"The results of the review were very clear - we found that for current smoking there was an increase in dementia risk of between 40 and 80 per cent," she said.

Those who were at most risk of declining brain function were smokers who continued the habit into their middle and later years.

"This paper really shows for the first time that very clearly that current smoking is a risk factor for dementia and it really puts a lot of weight behind a public health message that smoking is not only a risk for things like lung cancer, it is also a risk factor for dementia," she said.

The research did not identify why smoking might lead to cognitive decline, although it suggested smokers might have poorer general health and be less likely to undertake regular exercise.

They also speculate that people who have a particular gene might even be more likely to get dementia if they smoke and that cigarette smoking might also interact with other risk factors for cardiovascular disease.

Associate Professor Anstey says the link between smoking and brain decline was found in all kinds of dementia.

"We actually looked at Alzheimer's disease, vascular dementia, any dementia and cognitive decline and we found the smoking increased the risk of any of those cognitive outcomes," she said.

Researchers say the findings are important.

With the rates of dementia predicted to rise steeply with Australia's ageing population, there is a urgent need to identify any modifiable risk factors for cognitive decline.

The paper has been published in the American Journal of Epidemiology.

Topics: smoking, health, diseases-and-disorders, alzheimers-and-dementia, australia

First posted June 16, 2007 11:35:00