THURSDAY, Dec. 13, 2001 (HealthDayNews) -- In another tantalizing clue to the causes of Alzheimer's disease, a Swedish study finds that children who spend less than eight years in school have an increased risk of developing the mind-robbing condition many decades later.
Studying nearly 1,000 people 75 and older, researchers at the Karolinska Institute, in Stockholm, found that those who had less than eight years of education were 2.8 times more likely to suffer Alzheimer's disease than those who went on to high school or college.
The study is the latest to link schooling and Alzheimer's disease, but the cause-and-effect relationship is not clear, says Dr. Zaven Khachaturian, former director of the office of Alzheimer's research at the National Institutes of Health.
"The question that comes up immediately is whether education is a protective therapy," says Khachaturian. "There is a lot of speculation, but we do not know what the mechanism is. One speculation is that education could be a surrogate for another phenomenon, like better diet. Another is that education or a challenging profession increases the number of synapses in the brain."
Synapses are the connections between nerve cells in the brain. The brain is a "highly dynamic system" in which synapses are constantly forming, Khachaturian says, and "the more you stimulate the brain, the more rich the environment, the more rich the synapses. So the speculation is that those with a higher education have a higher density of synaptic connections, and it takes a longer time for them to lose it."
Reporting in the December issue of Archives of Neurology, the Swedish researchers list several possibilities. It may be that education increases the number of synapses (the "brain reserve" hypothesis), they say, or that education helps people cope better with pathological brain changes (the "cognitive reserve" hypothesis), or that people with more education have generally healthier lifestyles that spare them from environmental assaults that diminish brain function (the "brain battering" hypothesis).
One hopeful aspect of these speculations is that mental activity later in life might help prevent Alzheimer's disease or slow its onset, Khachaturian says: "The metaphor is a tree with a lot of leaves. It takes longer for all of them to come down than for a tree where leaves are sparse."
The study of the relationship between mental activity and Alzheimer's was pioneered two decades ago by Dr. Robert Katzman, then at the Albert Einstein College of Medicine, in the Bronx, and now director emeritus at the Alzheimer's Disease Research Center of the University of California, San Diego. In one of his studies, Katzman looked at Shanghai residents and found that women with no education had a higher risk of Alzheimer's disease.
Education and its beneficial effects need not end early in life, Khachaturian says. "I still recommend that older people keep their minds active, take up challenging tasks, do puzzles, push the limits of their mind," he says. "Anyone can benefit from taking on tasks that are challenging to them. We can use that prescription for all kinds of people at all levels of education."
The basis of the link is a puzzlement, says Bill Thies, vice president for medical and scientific affairs of the Alzheimer's Association: "We don't know whether people with higher education start off with better equipment to begin with."
And he adds a word of caution: "If you are highly educated, you can take some comfort, but it is only statistical comfort. Lots of highly educated people develop Alzheimer's disease. It is an equal opportunity condition."
What To Do
"As long as you stimulate the brain, picking up challenges in fields that are not familiar to you, like fixing a car or taking music lessons or learning a language, you can get benefits," says Khachaturian.
You can get more information about Alzheimer's disease from the Alzheimer's Association or the Alzheimer's Disease Education & Referral Center.
