Heavy smokers increase dementia risk26th October 2010
People who have reached middle age and still smoke heavily have a high risk of developing Alzheimer's disease, according to a joint US-Finnish study.
The researchers studied middle-aged heavy smokers, followed them up 20 years later, and found that about a quarter of the study subjects had developed dementia.
Due to the fact that smokers die from a variety of causes, researchers often find it difficult to assess the effects of smoking on the brain.
The original data set comprised 21,123 people, all of whom participated in a survey between 1978 and 1985.
Minna Rusanen from the University of Eastern Finland and Kuopio University Hospital said that her team's study suggested that heavy smoking in middle age increased the risk of both Alzheimer's disease and vascular dementia for men and women across different ethnic groups.
She said that the large detrimental impact of smoking increased as population aged.
Rachel Whitmer, a research scientist with Kaiser Permanente in Oakland, California, who also took part in the study, said that the increased dementia risk was not just for heavy smokers, and that moderate smokers were also in danger of getting dementia.
The researchers found that 5,367, or about 25% of the people who participated in the initial study, had dementia at follow-up time.
Researchers followed up with the people who were surveyed, all of them patients in one region of the US, between 1994 and 2008.
Fully 1,136 of the 5,367 patients had Alzheimers, and 416 had vascular dementia.
When the researchers followed up with the original study subjects, most of the patients were about 70 years old.
When compared to non-smokers, the people who smoked more than two packs of cigarettes a day had the highest risk of developing dementia and Alzheimer's disease.
The researchers said that theirs was the first study demonstrating a pervasive, multiethnic long-term dementia risk from midlife smoking.
About 25% of the group, 5,367 volunteers in total, were diagnosed with some form of dementia in the more than 20 years of follow up, including 1,136 people who were diagnosed with Alzheimer's disease.
Alzheimer's, the most common form of dementia, is a fatal brain disease in which people gradually lose their memory and their ability to reason and care for themselves. It affects more than 26 million people globally.
People who smoked more than two packs of cigarettes a day had a higher risk of both Alzheimer's disease and vascular dementia.
Whitmer said that, compared with non-smokers, people who smoked two packs a day had a 114% higher chance of dementia, a 157% higher risk of getting Alzheimer's disease, and a 172% higher risk of getting vascular dementia.
She said that the study was the first of its kind to probe greater lengths of time in its statistical analyses, and that the finding confirmed researchers' suspicions that the brain was susceptible to smoking-related degeneration.
The worldwide costs of caring for dementia may triple in 40 years, and already accounts for about 1% of global GDP output, according to the World Health Organisation (WHO).
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Title: Heavy smokers increase dementia risk
Author: Luisetta Mudie
Article Id: 16503
Date Added: 26th Oct 2010