Choosing an optimal self-report physical activity measure for older adults: does function matter?
physical activity, healthy aging, and physical function
Download 132.74 Kb.
|
- Navigate this page:
- 1.3measurement of physical activity in older adults
1.2physical activity, healthy aging, and physical functionThe relationship between physical activity and healthy aging has been a long-standing topic of interest in the research community. Epidemiological studies indicate that increased physical activity, in general, in older adults can lead to more favorable health outcomes such as increased physical capacity and a reduced the risk of comorbidity and even mortality.11-17 Evidence exists from the Lifestyle Interventions and Independence for Elders (LIFE) study and the Health, Aging, and Body Composition (Health ABC) study that any type of physical activity is better than no physical activity for protection against mobility impairment and other physical function limitations.13,14 This association between physical activity and prevention of physical limitations can be understood in the context of the disablement process. Verbrugge and Jette describe the disablement process as how chronic and acute conditions affect functioning in specific body systems, generic physical and mental actions, and activities of daily life, as well as how the personal and environmental factors speed or slow disablement (e.g. risk factors, interventions, etc.).18 Physical activity plays an important role in the prevention or delay of the disablement process caused by aging. A recent meta-analysis showed that physical activity is an effective strategy in preventing and reducing disability, maintaining independence and reducing health care cost in aging societies.19 The investigators reported that physical activity in older adults at moderate/high levels reduced risk incident disability by 49% and risk progressive disability by 45%.19 The Lifestyle Interventions and Independence for Elders Pilot (LIFE-P) investigated the relationship between physical function and moderate-to-vigorous physical activity in 424 older adults aged 70-89 years at risk for mobility-disability.20 The LIFE-P study used the Short Physical Performance Battery (SPPB) and the 400m walk test to determine baseline levels of physical function.21 The Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire was used to measure self-reported moderate-to-vigorous physical activity (MVPA) levels in participants.21 The investigators found that self-reported MVPA was associated with physical function on both the SPPB and 400m walk test, with mean SPPB scores for participants reporting ≥150 min/week of MVPA significantly higher (7.96 ± 1.16) than those reporting <150 min/week of MVPA (7.38 ± 1.47; p=0.0006). The mean 400m walk time for participants reporting <150 min/week of MVPA was significantly higher (8.37 ± 1.95 min) than those reporting ≥150 min/week of MVPA (7.55 ± 1.56 min; p=0.0003).20 A more recent literature review of mobility limitations in older adults suggested that addressing functional deficits with physical activity can improve physical function and quality of life for older adults with mobility impairment.22 However, many older adults are well-functioning and have minimal mobility impairment. For this reason, it is important to differentiate between the different levels of physical function when considering effects of physical activity. Levels of physical function in older adults are measured on a spectrum ranging from lower level functioning to higher level functioning. For example, the SPPB is used to assess a broad range of lower extremity function in older adults23; however, there is evidence that the SPPB does not distinguish ability at the higher end of the spectrum24. For these higher level functioning adults, the Health ABC modified battery (modified SPPB) is often used.25 1.3measurement of physical activity in older adultsA valid evaluation of physical activity in older adults is imperative for the progression of knowledge regarding associations of physical activity and health outcomes. There are both subjective and objective tools available for measuring physical activity in older adults. Both types of measurements of physical activity can be beneficial and problematic. Subjective measures, such as self-report questionnaires, can be administered for a low cost, using minimal time, and minimal participant burden; however, these self-report questionnaires are prone to recall bias and can be inaccurate for capturing irregular and low-intensity physical activity.26 Two common subjective tools used in measuring physical activity in older adults are the Physical Activity Scale for the Elderly (PASE) and the Community Healthy Activities Model Program for Seniors questionnaires. Both the PASE27 and the CHAMPS28 have been validated against the doubly labeled water (DLW) method to classify healthy older adults into levels of physical activity. For the PASE, the physical activity ratio, or the ratio of total energy expenditure and resting metabolic rate, as measured by the DLW method, was significant and moderate-highly correlated with the PASE score (r=0.68, p<0.01).27 For the CHAMPS, the physical activity energy expenditure, as measured by the DLW method, was borderline significant and weakly correlated with the CHAMPS score (r=0.28, p=0.04).28 Although the CHAMPS was weakly associated with DLW physical activity energy expenditure, it was the only questionnaire, of three self-report questionnaires examined, that was significantly correlated.28 These associations indicate that these two questionnaires are adequate for use in epidemiologic studies.27,28 In addition to these self-report questionnaires of physical activity, questionnaires are available to measure sedentary behavior and sedentary time in older adults.29 Although the PASE and CHAMPS capture sedentary behavior, it is not included in the scoring of these two questionnaires; furthermore, they are not intended to measure sedentary time. For the PASE, two sedentary behavior questions are asked which include sitting activities such as reading, watching TV or doing handcrafts and work/volunteer, mainly sitting with slight arm movements. The CHAMPS is more extensive, asking twelve questions about sedentary behaviors including using a computer, doing woodwork/needlework/drawing, and reading. Of the two questionnaires, the CHAMPS queries multiple types of sedentary behavior as well as the duration of each item, whereas the PASE does not. Further, the CHAMPS may be the better tool of the two for assessing sedentary behavior. Because sedentary behavior has independent effects from physical activity on mobility disability in older adults30, this is beyond the scope of this essay. Objective measures are often used to validate self-reported measurements.26 These are considered the “gold standard” for obtaining physical activity data, as they are less prone to response and recall biases; however, these measures are higher in cost, more time consuming, and are higher in participant burden.26 Also, there is a lack of consensus regarding cut points to categorize activity levels using objective measures. Devices, such as accelerometers and pedometers, are often used for measuring physical activity in older adults.31 Although, these types of devices provide epoch lengths, cut points, and thresholds for physical activity, they cannot distinguish between intensity levels of physical activity and may not be suitable for certain types of physical activity (e.g. water sports, resistance exercise, cycling, etc.).26 More recently, the SenseWear Armband (SWA) has emerged as an objective device for measuring physical activity in older adults in epidemiologic studies. Mackey et al., validated the SWA estimate of physical activity energy expenditure against the DLW method for measuring both total energy expenditure and activity energy expenditure in older adults in 19 older adults, mean age 82 years, participating in an ancillary study to Health ABC.32 The associations between the SWA total energy expenditure and activity energy expenditure and the DLW method were significant and highly correlated, respectively (r=0.89, p<.001; r=0.76, p<.001).32 In addition to measuring physical activity intensity and time, the SWA is also capable of measuring sedentary behavior and sedentary time in older adults. However, to be comparable with the self-reported measures, we set a threshold of intensity level for duration of physical activity from the SWA to capture activities >1.5 METS.
Download 132.74 Kb. Share with your friends:
|