WASHINGTON — Adults with hobbies that exercise their brains — such as reading, jigsaw puzzles or chess — are 2 1/2 times less likely to have Alzheimer's disease, while leisure limited to TV watching may increase the risk, a study says.
A survey of people in their 70s showed that those who regularly participated in hobbies that were intellectually challenging during their younger adult years tended to be protected from Alzheimer's disease. The finding supports other studies showing that brain power unused is brain power lost.
The study is also more bad news for the couch potato, said Dr. Robert P. Friedland, first author of the research appearing Tuesday in the Proceedings of the National Academy of Sciences.
"Television watching is not protective and may even be a risk factor for Alzheimer's disease," said Friedland, an associate professor of neurology at Case Western Reserve University School of Medicine and member of the medical staff at University Hospitals of Cleveland.
Dr. Zaven Khachaturian, senior medical adviser to the Alzheimer's Association, said the study is important because it supports other research showing that the onset of Alzheimer's is delayed by education and by intellectually demanding professions.
In the study, Friedland and his co-authors analyzed the leisure activities in young and middle adulthood of 193 Alzheimer's patients and of 358 controls, people who did not have symptoms of the disease. All the participants were in their 70s when the survey was conducted.
The information about the Alzheimer's patients was gathered from family and friends, while the others were interviewed directly.
The researchers gathered information on how the subjects spent their leisure time during their early adulthood, age 20 to 39, and during their middle adulthood, age 40 to 60. The survey centered on three types of activities:
Passive, such as watching television, talking on the phone or listening to music.
Intellectual, such as reading, jigsaw or crossword puzzles, playing musical instruments, chess or other board games, knitting or woodwork.
Physical, such as baseball, football or other sports, bike riding, swimming, walking or skating.
"The Alzheimer's patients were less active in all these activities except for television watching," said Friedland.
Intellectual activities seemed particularly protective, he said, noting that those whose leisure centered on mind-challenging hobbies were about 2 1/2 times less likely to develop Alzheimer's.
Friedland said that the effect comes from activities between the ages of 20 to 60. He said the results were adjusted for the known beneficial effects on Alzheimer's of education and intellectually demanding professions. No matter the profession or the amount of education, he said, there still was a beneficial effect.
Intellectual stimulation in early and middle adulthood does not absolutely protect against Alzheimer's in late adulthood, said Friedland, but the activities could delay the disease for years.
"The brain is an organ just like every other organ in the body. It ages in regard to how it is used. Just as physical activity strengthens the heart, muscles and bones, intellectual activity strengthens the brain against disease."
It's believed, he said, that healthier brain cells are better able to control or slow Alzheimer.
Khachaturian said the effect seems to be that brain-challenging activities "build up a reserve" of neuron connections. Because of this reserve, said Khachaturian, it takes longer for the Alzheimer's process to destroy enough neurons for there to be identifiable symptoms.
"Intellectual stimulation may delay the onset," said Khachaturian. "There is no evidence, however, that it will actually alter the disease course."
But delaying the disease onset, he said, could give many more years of rational life for people who eventually develop the disease.
Alzheimer's disease is a fatal, brain-destroying disorder that is generally diagnosed after the age of 60. The disease progressively destroys memory and eventually, the ability to care for oneself. There are about 4 million Americans diagnosed now, but that number is expected to jump to 14 million by 2050 as U.S. society ages. The disease is thought to affect about one in 10 people age 65 or older, and about half of everyone over the age of 85.
The formation in the brain of protein-based plaques that destroy neurons or brain cells has been identified as the prime disease process, but no cure has been found.
On the Net: Alzheimer's Association: www.alz.org/