February 28 - 29, 2008 Advisory Committee Meeting Minutes

Subcommittee Report: Special Populations

James Rimmer, Ph.D., presented the subcommittee report on disabilities. The major areas of the report are:

  1. What is the strength of the evidence on exercise/physical activity and health outcomes in people with physical and cognitive disabilities?

  2. Is there any evidence of a dose-response pattern in people with disabilities?

  3. What is the incidence of reported adverse events in people with disabilities involved in various exercise exposures?

The structure of the report will be based on the following health outcomes: Cardio-respiratory health, musculoskeletal health, metabolic health, energy balance and maintenance of healthy weight, functional health, mental health and secondary conditions. The initial CDC database had only 4 articles on relevant to disabilities so additional searches had to be done resulting in another 139 articles. The majority of the studies focused on strokes and amputees. The subcommittee organized the data by levels of evidence as follows:

  • Strong: 2 or more RCTs with positive results and no studies reporting significant negative effects.

  • Moderate: 1 RCT with positive results and no studies reporting significant negative effects.

  • Limited: At least 1 non-RCT with positive results and no studies with significant negative effects.

  • No evidence: Non-significant findings or no studies investigating the effects of exercise.

The consistency of evidence supports the use of physical activity to improve key health outcomes in people with physical and cognitive disabilities. In the area of physical disability the strongest evidence lies in the categories of cardio-respiratory, musculoskeletal and mental health. For cognitive disabilities, the strongest evidence of benefit is in the areas of functional and mental health. Very few of the studies reported serious adverse events. The majority of the studies included exercise doses typically used in studies with the general population:

  • Intensity — more than 50% HRR or VO2peak

  • Frequency — 3 to 5 days per week

  • Duration — 30 – 60 minutes

Future research needs include well-designed, adequately powered, prospective cohort studies targeting key health outcomes in all disability groups. There is also a need to develop infrastructure for multi-center clinical exercise trials to reach low incidence/low interest populations as well as a need to examine the dose-response effects of very low doses of exercise in severely de-conditioned disabled populations. To better evaluate data there is a need for a common set of instruments for each targeted health outcome with good psychometric properties. Because of intra and inter individual variability within and between disability groups, categorizing subjects by function rather than disability may be a viable approach to building the evidence across multiple disability groups.

Race, Ethnicity and Social Economic Status
Antronette Yancey, M.D., M.P.H., presented the subcommittee report on race, ethnicity and social economic status (SES). The subcommittee was charged with researching whether there is evidence to support the need for different physical activity recommendations based on race, ethnicity and SES. The major questions the group reviewed focused on what types of differences could there be and what they would mean based on race and SES and included the following:

  1. Are there differences in the energy cost of physical activity, such that some ethnic groups appear to derive lesser benefits for weight maintenance at the same level of physical activity because of racial differences in body morphology and consequently BMR.

  2. Are there differences created by the influence of baseline physical activity such that different approaches are necessary for ethnic groups having farther to go to reach physical activity goals.

  3. Are there differences created by the influence of baseline physical inactivity or overweight status, such that different approaches are necessary for ethnic groups having farther to go to reach the goal.

  4. Are there differences in adherence to various types of physical activity with implications for long-term sustainability and weight stability as a result of different cultural values and preferences, environmental exposures, and social (in)justices issues.

  5. Are there differences in accuracy of measurement of physical activity such as an inability of activity monitoring devices or survey assessment tools to adequately capture range or intensities of activities, such that research studies are unable to discern real differences in energy expenditure.

From the literature 86% of 231 articles in a meta-analysis of RCTs examining the effects of diet and exercise on weight and fitness related outcomes did not report race/ethnicity, compared with 11% and 4% respectively, failing to report age and gender. Studies that do not report race/ethnicity have overwhelmingly white samples. Few studies targeting ethnic minorities were population-based and very few compared racial/ethic groups. There were also disproportionately few studies of Latinos, American Indians, and Asian/Pacific Islanders.

There is insufficient evidence to conclude that physical activity recommendations should be different for different racial/ethnic or SES groups. Most individuals from ethnic/gender and/or lower SES groups are relatively sedentary and overweight, such that the benefits of integrating small amounts of physical activity during the workday and school day should be explored because of promising but preliminary practice-based evidence of such benefits as decreased anxiety, weight stabilization, and injury prevention.

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