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Identifying health and other problems that increase older adults’ risks of becoming disabled or dying early is important. By identifying these "risk factors" and finding ways to address them, researchers can help lower risks of disability and early death.

Some research suggests that older people who get lower scores on the digit symbol substitution test and those who have slower walking speeds may run higher risks of developing physical disability and early death. The digit symbol substitution test (DSST) measures cognitive abilities such as attention and memory.

New Research in the Journal of the American Geriatrics Society

Investigating further, researchers recently studied more than 3,000 older men and women– their average age was 70 – over the course of more than 8 years. All of the participants of this study lived in the community, rather than in nursing homes or other facilities. None had suffered strokes or had dementia or had physical disabilities at the start of the study.

At the start of the study, the researchers gave each of the participants the DSST and measured the walking speed. By the end of the study, those who had earned lower scores on the DSST at the start of the study were more likely to have died or have become disabled than those who had earned higher scores on the test, the researchers found. They also found that men who had slower walking speeds at the start of the study were more likely to die or become disabled over the 8-year period than those who had faster walking speeds. Moreover, men who had both lower DSST scores and slower walking speed ran an even higher risk of becoming disabled or dying early, the researchers report in the Journal of the American Geriatrics Society.

These results suggest that low DSST scores and slow walking speed may be signs of early brain changes which in turn boost risks of disability and early death, the researchers report. In light of this, offering older adults with low DSST scores and slow walking speeds treatments to address these changes could help prevent disability and early death, they suggest. Among other things, physical exercise and cognitive activities that give the brain a "mental workout" have been shown to boost cognition and improve physical fitness in older people, the researchers note.

Additional studies investigating links between disability and early death on one hand and the DSST, walking speed, and other measures of thinking and physical ability on the other hand, are needed, the researchers conclude.

What Should I Do?

For more information about the health benefits of physical exercise, and advice on exercising in later life, visit the Exercise Chapter on Aging in the Know

For more information about and advice on staying mentally sharp in later life, take a look at the Cognitive Vitality Tip Sheet

The summary above is from the full report titled, "Lower Digit Symbol Substitution Test Score and Slower Gait are Associated with Greater Risk of Mortality and of Developing Incident Disability in Well Functioning Older Adults." It is in the September 2008 issue of the Journal of the American Geriatrics Society (Volume 56, Issue 9). The report is authored by Caterina Rosano, MD, MPH, Anne B. Newman, MD, MPH, Ronit Katz, PhD, Calvin H. Hirsch, MD, and Lewis H. Kuller, MD, DrPh.