Friday, June 13, 2008

Poor Memory Because of Smoking: The Contribution of Smoking to Dementia

24-7 -- A recent study suggests that smoking may accelerate the development of dementia—a gradually progressive brain disorder that contributes to memory loss. Researchers from the Institut National de la Sant et de la Recherche M dicale, Villejuif, France used several studies done in the past to determine the additional health risks of smoking.

The researchers found out that smoking appears to heighten the risk of memory loss. However, it is still unclear if smoking has a direct effect on cognition (perception, intelligence, and learning). This is difficult to attain because older adults included in the study failed to return for follow-up visits, or had died of smoking-related ailments in the intervening time.

S verine Sabia, M.Sc., of the Institut National de la Sant et de la Recherche M dicale, Villejuif, France, and colleagues examined data from 10,308 London-based civil servants age 35 to 55, who enrolled in the Whitehall II study between 1985 and 1988.

Smoking habits were regularly evaluated between the years 1997 and 1999. The study included 5,388 participants who completed memory, vocabulary, reasoning, and verbal fluency examinations. Of these participants, only 4,659 were re-tested after five years.

The study suggests that those who smoked at the beginning of the study have heightened risk of dying during the average 17.1 years of follow-up. In addition to this, smokers were less likely to participate in cognitive testing. At the first round of cognitive testing, smokers were found to be more likely to perform poorly compared to their non-smoking counterparts. They were ranked in the lowest performing group, with 20 percent being the lowest score.

Former smokers at the beginning of the study, on the other hand, were 30 percent less likely to have poor vocabulary and low verbal frequency scores compared to their smoking counterparts.

Individuals who cut the habit during the course of the study also experienced significant improvement in other habits, such as being more physically active, eating healthier diets which consists of more fruits and vegetables, and drinking less alcohol.

"This study presents four key findings," the authors wrote. "First, smoking in middle age is associated with memory deficits and a decline in reasoning abilities. Second, long-term ex-smokers are less likely to have cognitive deficits in memory, vocabulary, and verbal fluency. Third, giving up smoking in midlife is accompanied by improvement in other health behaviors. Fourth, our results based on a large prospective cohort study of middle-aged British civil servants suggests that the association between smoking and cognition, even in late midlife, could be underestimated because of higher risk of death and non-participation in cognitive tests among smokers."

The study is hailed by many health specialists as a medical breakthrough because individuals who experience cognitive impairment may have heightened risks of developing dementia at a faster rate.

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