Between January 2003 and November 2009, 629 subjects were measured on their grip strength, standing balance, ability to walk four meters, and ability to do five chair stands. Each task was scored from 0 (unable to perform) to 4 (best performance).
The average age of participants was 94, and most — 72.5 percent — were women. A quarter were classified as having dementia. Those who scored lower on the tasks were more likely to be among this group.
“The results reveal that even modest declines in physical performance are associated with increased odds of dementia. The strongest association is seen with gait slowing, followed by five chair stands, grip strength and standing balance,” said Dr. Szofia Bullain, study leader and a clinical instructor and fellow in UCI’s Department of Neurology.
Findings appear online today in Archives of Neurology, a JAMA Network publication. Individuals 90 and older constitute a unique segment of society that has not been well studied, Bullain said. Previous research has suggested a relationship between poor physical performance and cognitive impairment in elderly populations under 90.
Participants who were unable to walk were almost 30 times more likely to have dementia than those with the fastest walking times. Subjects with even minimal slowing of walking speed (warranting a score of 3) were four times more likely to have dementia, according to the results.
“In summary, similar to findings in younger elderly populations, our study found that poor physical performance is associated with increased odds of dementia in the oldest old. The establishment of this association may serve as a major stepping stone to further investigate whether poor physical performance is in the causal pathway and a potentially modifiable risk factor for late-age dementia,” said 90+ Study primary investigator Dr. Claudia Kawas, the Nichols Term Chair in Neuroscience and a professor of neurology and neurobiology & behavior.
The research does not imply that a decreasing ability to perform physical tasks is a cause or a result of dementia; it simply illustrates the relationship between the two for people in their 90s.
Maria Corrada-Bravo, Barbara Agee Shah and Dr. Farah Mozaffar of UCI MIND also contributed to the study, which was supported by grants R01-AG-21055 and T-32-AG-000096 from the National Institute on Aging, one of the National Institutes of Health.
About the 90+ Study
The 90+ Study was initiated in 2003 to learn more about the oldest old, the fastest-growing age group in the United States. It’s among the largest studies of the oldest old in the world. More than 1,600 participants have enrolled, including many residents of Leisure World in Laguna Woods, Calif., one of the nation’s biggest retirement communities. Because little is known about people who reach their 90s, the remarkable increase in the number of oldest old presents a public health challenge to promote the quality — as well as the quantity — of life.
Researchers in the 90+ Study have published many scientific papers in premier journals. Some of the major findings are:
- People who drink moderate amounts of alcohol or coffee live longer than those who abstain.
- People overweight in their 70s live longer than normal or underweight people do.
- The risk of developing dementia continues to double with every five years of age and is as high as 40 percent per year in centenarians.
- More than 40 percent of people 90 and older suffer from dementia, while almost 80 percent are disabled. Both conditions are more common in women than men.
- About half of people with dementia over age 90 do not have sufficient neuropathology in their brains to explain their cognitive loss.
- People 90 and older with an ApoE2 gene are less likely to have clinical Alzheimer’s dementia but are much more likely to have Alzheimer’s neuropathology in their brains.
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