Physical activity could reduce Alzheimer’s risk, study finds
■ Researchers say a direct link between mental and physical fitness and the prevention of dementia-related diseases hasn’t been found, but recommending more activity can’t hurt.
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Being physically active may help reduce one’s risk of developing Alzheimer’s disease, even in older patients, according to a study published online April 18 in Neurology.
The study is one of the first to look at a range of physical activities, instead of strictly focusing on exercise. “There is accumulating evidence to suggest that a whole range of late-life activity is important in maintaining cognitive ability,” said Aron S. Buchman, MD, associate professor of neurological sciences at Rush University Medical Center in Chicago.
The study is among the latest of several to suggest a link between mental and physical activity and long-term cognitive health. Some Alzheimer’s researchers say the clinical evidence isn’t yet strong enough to bolster such recommendations with sure-fire results, but they say it can’t hurt for physicians to recommend to their older patients that they stay mentally and physically active.
For the Neurology study, researchers used devices called actigraphs to monitor all types of physical activity in 716 individuals who did not have dementia, with an average age of 82. “Whether they’re preparing food, getting out of their chair, walking around their house or chopping onions, it was going to be recorded as physical activity,” Dr. Buchman said.
The subjects were given cognitive tests, and researchers found that those who were most physically active were significantly less likely to develop cognitive problems. Over the mean of 3½ years of follow-up, 71 participants developed Alzheimer’s disease, with those in the bottom 10% of daily physical activity being more than twice as likely to develop the disease.
Another study published online Jan. 23 in Archives of Neurology indicated that participating in mental activities, such as reading, writing and games, reduced the risk of developing a protein in the brain that is associated with Alzheimer’s disease.
Researchers examined 65 patients with a mean age of 76, 10 Alzheimer’s patients and 11 younger adults (mean age 25) from Oct. 31, 2005, to Feb. 22, 2011. Patients self-reported their participation in cognitive activities and underwent scans to measure the presence of the protein amyloid in the brain. The study found that people who participated in the most mental activities had reduced risk of developing the protein.
“We think that having amyloid in the brain leads to Alzheimer’s, but we don’t have all of the answers yet,” said Susan M. Landau, PhD, lead study author and a research scientist at the University of California, Berkeley.
To influence treatments on a broad scale, the benefits highlighted in these studies must be proven through double-blind clinical studies, said Michal Schnaider Beeri, PhD, associate professor of psychiatry at Mount Sinai School of Medicine in New York. “There is a long process before you prove that a particular intervention is truly, positively related to positive outcomes,” said Beeri, who co-wrote an editorial on the Neurology study.
But Beeri said she sees no harm in recommending that patients be more active as they go about their daily routines. Even small changes can make a difference over the course of a day.
“Even if you are physically limited — if you can talk with your hands or cook or move around in your wheelchair, it is better than if you don’t,” she said.
Samuel Gandy, MD, PhD, professor of neurology and psychiatry and chair at the Mount Sinai Alzheimer’s Disease Research Center at Mount Sinai School of Medicine and James J. Peters VA Medical Center, said that only one randomized clinical trial has examined the impact of lifestyle on Alzheimer’s disease.
The 2007 study in the Journal of the American Geriatrics Society showed that exercise slows progression of the disease. Researchers studied 134 patients at five nursing homes with mild to severe Alzheimer’s disease over 12 months. They found that progression was slowed by about a third in patients who engaged in a moderate exercise program with an occupational therapist one hour twice a week.
“This strongly supports the idea that physical exercise will delay onset,” Dr. Gandy said.
Research that examines the role of lifestyle behavior on long-term cognitive ability is particularly important given the aging population and the health system’s limited resources, especially since such interventions come with minimal costs, Dr. Buchman said.
About one in eight older Americans, or 5.4 million, has Alzheimer’s disease, according to the Alzheimer’s Assn. It is the sixth-leading cause of death in the U.S., with care costing an estimated $200 billion in 2012.
Worldwide, the number of people with dementia is expected to more than triple from 35.6 million to 115.4 million by 2050, according to an April 11 report from the World Health Organization and Alzheimer’s Disease International.