People who spend years studying at university may be inadvertently protecting themselves against severe Alzheimer's disease, a study suggests.
Alzheimer's can affect memory and learning skills
Scientists in the United States have found evidence to suggest that a formal education protects against the more devastating aspects of the disease.
They have discovered a direct link between the amount of time spent studying and the loss of memory and learning skills in people with Alzheimer's.
The scientists believe that a long history of education may enable the brain to cope better with the effects of the disease.
Dr David Bennett and colleagues at Rush Presbyterian-St Luke's Medical Center in Chicago examined the brains of 130 people who had been diagnosed with Alzheimer's before they died.
Their education levels varied although 90% had gone to college. This ranged from a few years of undergraduate study to high levels of postgraduate work.
[Education] may make the brain more adaptable and flexible
All of these people had undergone tests about eight months before their death.
The tests examined their cognitive abilities - their ability to memorise and process information and their ability to accurately reach for objects within their visual field.
They found that the longer people spent in formal education the better they performed in these tests.
This was irrespective of the amount of amyloid plaques - proteins which clump together to kill cells - in their brains. These plaques are known to cause Alzheimer's.
Writing in the journal Neurology, the scientists suggested that years of education could help to build up a reserve which can help the brain to cope better in the event of Alzheimer's disease.
"[Education] may make the brain more adaptable and flexible," Dr Bennett said.
Dr Neil Buckholtz, head of the US National Institute on Aging, backed that view.
"These findings give us additional insight into the long-known but well understood link between education and everyday memory and learning ability," he said.
"It may be that education permits the brain already affected by the pathology of Alzheimer's disease to work around that damage and allow an individual to function at a higher level."