The number of people living well into their 90s is projected to quadruple by 2050. By mid-century, nearly 9 million people will be 90-years-old or older. In a first-of-its-kind study published in the Journal of the American Geriatrics Society, researchers from the University of California at Irvine examined whether four different measures of poor physical performance might be linked to increased dementia risk for people aged 90 and older.
Previous studies have shown that poor physical performance is linked to increased odds for dementia in people younger than 85. But until now, we didn't know whether a link between poor physical performance and dementia existed for people 90 and older.
The researchers examined 578 people aged 90 and older who were participants in The 90+ Study, a community-based longitudinal study—a research method that follows the same subjects repeatedly over a period of time—of the oldest-old in Southern California. Examiners see the participants every six months to conduct physical and neurological examinations as well as cognitive tests, with the goal of looking critically at aging and dementia specifically.
At the start of the study, about 50 percent of the participants were cognitively impaired (had trouble thinking or remembering), but did not have dementia. The rest were cognitively normal. Researchers followed the participants for 2.6 years and, during that time, almost 40 percent of participants developed dementia.
The researchers observed a unique link between dementia risk and poor performance on two different physical performance tests: the standing balance test and the four-meter (about 13 feet) walking test.
The researchers suggested that, since walking and standing balance require complex brain activity, testing these functions may help doctors predict who among the "oldest-old" might be most at risk for developing dementia. The researchers also note that future studies could lead to the development of prevention programs and treatment strategies.
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Bullain SS et al. Sound Body Sound Mind? Physical Performance and the Risk of Dementia in the Oldest-Old: The 90+ Study. Journal of the American Geriatrics Society, Published Online July 5 2016. doi: 10.1111/jgs.14224