Active mind cuts Alzheimer's risk, study says

February 13, 2002|By Ronald Kotulak, Tribune science reporter.

Adding to the growing evidence that the brain can rebuild itself throughout life, researchers have found that older people who engage in regular vigorous mental activity are nearly 50 percent less likely to develop Alzheimer's disease than people who put their brain on pause.

The findings further support claims that people can play a direct role in retaining their thinking capacity through such simple activities as reading, travel, working crossword puzzles and going to museums.

Even TV watching can be helpful if it is part of a variety of intellectual pursuits, the researchers said, but by itself TV is not an effective aid for memory retention.

The study of Catholic priests, nuns and brothers, reported on Wednesday in the Journal of the American Medical Association, showed that older people who participated in the highest level of routine intellectual activities were 47 percent less likely to develop Alzheimer's disease over a four- to five-year period than people who used their minds less frequently.

Conducted by researchers at Rush-Presbyterian-St. Luke's Medical Center in Chicago, the study is considered important because it is the first attempt to examine which lifestyle factors over time may protect against Alzheimer's disease.

The study is called prospective because the participants did not have dementia or Alzheimer's disease when they entered the study and the researchers were able to control for such factors as age, income and education. Previous studies were retrospective, which means that they asked participants to recall their past behavior, a less accurate method for determining links to a disease, especially among Alzheimer's patients who may already have suffered memory loss.

"It's the most direct evidence yet that remaining intellectually active when you're older may actually reduce your risk of getting Alzheimer's disease," said Robert Wilson, a Rush neuropsychologist.

Dr. David Bennett, director of Rush's Alzheimer's Disease Center, said the findings, which need to be verified in community studies now under way, could have widespread public health implications.

"It's not just you or me thinking about this and saying we should be more mentally active, but what do you do about older men and women living alone who don't have access to transportation or social contacts," he said.

"Maybe we need to start thinking as a society about what we want to do about that and make those kinds of things available to older people who might not be able to avail themselves otherwise."

It is estimated that more than 4 million Americans have Alzheimer's disease and that the number is expected to increase greatly in the near future as Baby Boomers age.

Religious orders take part

Rush's Religious Orders Study involves 801 nuns, priests and brothers age 65 and older from 40 groups around the country. They were enrolled starting in 1994 and followed for an average of 4.5 years. All participants agreed to donate their brains for study after death.

Although none of the participants had Alzheimer's disease when they entered the study, 111 of them developed the memory-robbing disorder.

"We are asked constantly about the use-it-or-lose-it approach to maintaining memory," said Elisabeth Koss, assistant director of the National Institute on Aging's Alzheimer's Disease Centers Program, which funded the Rush project.

"This study provides important new evidence that there may be something to the notion of increased cognitive activity and reduced risk of Alzheimer's disease," she said. "Further research should help sort out whether cognitive activities can be prescribed to reduce risk of [Alzheimer's disease] and why that may be so."

Many researchers believe that the brain responds to new learning experiences by building new connections between brain cells or strengthening existing ones, a process called plasticity.

Earlier studies showed that the brains of animals subjected to mentally stimulating environments had far more connections between brain cells than animals not mentally stimulated. The higher number of synaptic connections protected the animals from the memory loss of aging.

New brain cells

Recent studies with humans also showed that, contrary to earlier beliefs, older people continue to make new brain cells throughout life. Animal studies indicate that these new cells are only laid down as part of a memory tract if their birth is followed by new learning experiences.

"There is a lot of evidence out there that suggests that the brain has more plasticity than we had once thought and that it may be protective against dementia and Alzheimer's disease," Bennett said.

So far researchers have autopsied the brains of more than 150 nuns and priests to see if there are more connections between brain cells in people without Alzheimer's disease and to look for other factors that may have enabled them to keep their memories until the end. The results of this study are expected in a few months.