Smoking Hastens Decline of Aging Brain
Study suggests benefits of quitting even in old age
MONDAY, March 22 (HealthDayNews) -- Forget Hollywood images of creative geniuses puffing away on cigarettes: A new study suggests smoking slows mental function as you age.
European research involving more than 9,000 elderly people finds older smokers lose cognitive ability at rates five times faster than nonsmokers.
What's more, "the total amount smoked was associated with rate of decline; those who smoked more on average declined faster," says study author Dr. Alewijn Ott, an epidemiologist and biostatistician at the Erasmus Medical Center in Rotterdam, the Netherlands.
His team's findings appear in the March 23 issue of Neurology.
Doctors have long understood that smoking contributes to atherosclerosis, or "hardening of the arteries," which, in turn, raises the risk for stroke and serious brain damage. Less clear is the effect of smoking on daily mental function, especially on the aging brain.
In their study, Ott and his colleagues had 9,209 elderly persons aged 65 years or older take a standard neurological test used to measure cognitive function. Volunteers were also questioned as to their smoking history. All were re-tested two or three years later to assess rates of intellectual decline over time.
The researchers found significant differences between smokers and nonsmokers when it came to mental function. Out of a possible total test score of 30 points, individuals who had never smoked saw their mental abilities decline by just 0.03 points per year -- a normal, age-related decline.
However, chronic smokers posted much higher intellectual losses -- 0.16 points per year -- a rate more than five times that of nonsmokers.
According to Ott, the study suggests that quitting smoking "is perhaps even more important in elderly persons, who are known to have a vulnerable brain circulation." In fact, individuals who described themselves as "former smokers" had relatively low rates of decline -- just 0.06 points per year.
"Many elderly smokers think at their age it doesn't matter much anymore" whether they continue to smoke or quit, Ott says. "But our study shows that to stop smoking could still help."
Ott stresses the slight drops in mental function observed in the study are minor, probably not noticeable in daily life. Over time, however, they may add up. The average intellectual gap between a 65-year-old and an 85-year-old is approximately 1.5 points, he says.
The study results prove yet again that "there is no good reason on Earth for smoking," says Dr. William Thies, vice president for medical and scientific affairs at the Alzheimer's Association.
While the exact mechanisms behind smoking-linked cognitive decline remains unclear, Thies notes "chronic nicotine use invariably causes decreases in blood flow because it is such a strong stimulant for atherosclerosis." Smoking-linked atherosclerosis can also trigger silent infarctions, or "mini-strokes," that kill off millions of brain cells at a time. "If one suffers repeatedly from these minor or silent infarctions, this may lead to decreased brain performance," Ott says.
The notion that smoking might help prevent Alzheimer's disease is a myth as well, the experts contend. While early studies seemed to uncover some sort of smoking "brain benefit," this finding has since been overturned.
"As people have gone back to look at studies that are more carefully controlled for drop-out deaths caused by tobacco, it's pretty clear now that, at least in Alzheimer's disease -- and to a lesser extent in Parkinson's disease -- that there is no benefit of smoking, and in fact there's a trend toward it being hazardous," Thies says.
The European study should also help dispel the myth of cigarettes as an aid to inspired genius. While smokers may get a brief rush from their first few puffs, it probably won't produce the Great American Novel, Thies says. Nicotine "stimulates the central nervous system," he explains, but "general stimulation of the nervous system probably doesn't increase its functionality -- its functionality has to be stimulated in very subtle ways to actually make it work better."
Read about memory and the aging brain from the American Academy of Family Physicians. Get help to quit smoking from the American Lung Association.
SOURCES: Alewijn Ott, M.D., department of epidemiology and biostatistics, Erasmus Medical Center, Rotterdam, The Netherlands; William Thies, Ph.D., vice president, medical and scientific affairs, Alzheimer's Association; March 23, 2004, Neurology
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