Anthropometry of Wheeled Mobility Project: Final Report

3.2 Comparison of Sub-samples across Data Collection Sites

The primary purpose of expanding data collection to different sites was to increase the diversity of the overall sample. The Buffalo site, having recruited participants for close to 10 years had a relatively diverse sample of individuals recruited through the local Independent Living Center, a local VA medical center, and local adult care facilities. The Pittsburgh site recruited primarily through a local VA medical center. The Ithaca site recruited through local adult care facilities.

Not unexpectedly, large differences in WhMD users in terms of gender, age, years with disability and device type used were found (Table 3‒2). Pittsburgh had a much higher percentage of men WhMD users (73%) as compared to Ithaca (57%) and Buffalo (46%). It has been our experience that men are more likely to participate in the study, and the Buffalo site specifically targeted female WhMD users in our last phase of data collection to improve the representativeness of the data set in terms of gender. The median age of WhMD users was highest for the Ithaca site (74 years) followed by Buffalo (57 years) and Pittsburgh (44 years). Ithaca, and Buffalo in the later stages of data collection, recruited primarily from adult care facilities in order ensure that older WhMD users were well represented in the sample.

The disparities in the time WhMD users had their disabilities can also be explained by the differences in sampling approaches across the sites. By concentrating on veterans, the Pittsburgh site recruited WhMD users with disabilities for the largest number of median years (20 years) as compared to Buffalo (15 years) and Ithaca (10 years). This illustrates that the WhMD users recruited by Pittsburgh were more likely to experience their disability at an earlier age than the other two sites, while the WhMD users recruited by Ithaca were likely to have first experienced their disabilities at a much older age.

Table 3‒2: Gender, age and number of years with disability across sites.

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There were also large differences in the medical condition reported as being responsible for the need to use a WhMD across data collection sites (Table 3‒3). Pittsburgh by far had the largest percentage of spinal cord injured WhMD users and lowest percentage of orthopedic injuries and deformities. The greater percentage of acute injury related mobility impairments such as spinal cord injuries for the Pittsburgh site is expected given that most of its sample was recruited through a VA medical center. The Buffalo and Pittsburgh sites each had sub-samples with a diverse set of medical conditions.

Table 3‒3: Reported primary medical conditions among WhMD users across sites.

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* “Other” includes amputations, traumatic brain injuries, respiratory diseases and diabetes.

The disparities across the three sites in terms of the percentages of WhMD technologies were largest between the Ithaca and the other two sites (Table 3‒4). The Ithaca site measured a much higher percentage of manual wheelchair users than Pittsburgh and Buffalo, which is not surprising given the distribution ages and reported medical conditions for the Ithaca site.

Table 3‒4. Primary mobility device used among WhMD users across sites.

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Some of the research participants could not complete all of the functional anthropometric tests (i.e. grip strength, reach and maneuvering). The participation rates in these tests were evaluated for each of the sites. The participation rates for the reach and grip tests are summarized in Table 3‒5. Participation rates for the reach tests were lowest in Ithaca where the WhMD users tended to be much older than those of the other sites. The participation rates for the power grips were lowest in Pittsburgh, where there was the highest percentage of WhMD users with spinal cord injury.

Table 3‒5: Participation rates in the functional anthropometric tests for each site.

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