February 28 — 29, 2008 Advisory Committee Meeting Minutes

Subcommittee Report: Functional Health

Miriam Nelson, Ph.D., presented findings in functional health. Dr. Nelson noted the challenge of interpreting the data due to many different ways activity is measured. The subcommittee researched the following questions:

1. In middle-aged and older adults who do not have moderate/severe functional or role limitations, does regular physical activity prevent or delay the onset of substantial functional limitations and/or role limitations?

   Conclusions
   There is clear observational evidence that participation in regular activity is associated with a delay in the onset of moderate to severe functional or role limitations in middle-aged and older adults. The adults who reported regular activity at all measurement occasions were at the lowest risk for functional limitations. Studies that assessed change in physical activity over time consistently reported that change from lower levels of activity to higher levels of activity over tie was associated with reduced risk of limitations. Findings from the observational studies support a dose-response effect. The strength of the conclusions is limited by issues of confounding with observational studies. There is limited data on muscle strengthening, balance and flexibility activities. While there is a dose-response effect, it is difficult to make a statement about the amount of activity required for prevention. Finally, no conclusions can be made whether preventive benefits differ by race or ethnicity.

2. In older adults, who have functional or role limitations, does regular physical activity improve or maintain functional ability and role ability with aging?

   Conclusions
   Older adults can improve physiologic capacity with targeted exercise at any age. There is modest evidence that physical activity in older adults with existing limitations improves functional ability, especially in aerobic and muscle strengthening exercises. There is limited evidence that physical activity improves ability. Heterogeneity in the methods used to assess outcomes made it difficult to compare studies. It is unclear whether single mode interventions would be as successful as multi-modal interventions. There is not enough evidence to suggest a dose-response effect or what a threshold might be to improve function. Finally, the data does not suggest any differences among the races.

3. In older adults who are at increased risk for falls and fall-related injuries and does regular activity reduce the rates of falls and injuries?

   Conclusions
   There is strong evidence that participation in planned physical activity reduces falls in older adults with the greatest benefits seen in people with functional deficits. There is limited data that planned activity reduces injurious falls due to a lack of studies focused on this question. Strength and balance exercises seem the most beneficial; however there is some inconsistent data that suggests tai chi can reduce falls in older adults. There is very little data to support a dose-response effect or to establish a threshold at which benefits are seen. More studies are needed to focus on how activity may or may not reduce injurious falls as well as studies on race.

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