Background: Osteoporosis is a bone disease characterized by low bone mineral density (BMD) which is strongly associated with an increase in fracture risk. People with a spinal cord injury (SCI) experience rapid decline in BMD during the acute phase of injury, but the prospective bone changes are yet to be determined in the chronic phase. Resistance training (RT) is a common non-pharmaceutical intervention for treating osteoporosis. However, we are unsure if the benefits of RT outweigh the harms because adverse events (AEs) are not consistently monitored or reported in RT trials involving the healthy and clinical population.
Objectives: The purpose of this thesis was to examine considerations for designing and managing RT intervention studies involving the general adult population as well as people with chronic health conditions (e.g., SCI, osteoporosis). The specific objectives were: 1) to determine if there are any prospective bone changes in people with a chronic SCI which can be used to assess the timing of exercise interventions; 2) to determine the benefits and harms of RT on health outcomes in adults aged 18 years or older, compared to not participating in RT; 3a) to explore the experiences and perspectives of individuals with chronic health conditions who had an AE as a result of RT; 3b) to understand researchers' current practices and perspectives on AE reporting in RT, and identify barriers and facilitators of AE reporting; and 3c) to adapt AE reporting guidelines to exercise which can be used to increase the quality of published research with respect to safety of RT interventions. Overall, the objective of this thesis was to inform RT interventions with respect to timing, benefits and the proper reporting of harms.
Methods: To address the above objectives, this thesis consisted of three separate studies. Study 1 was a secondary data analysis of a two-year prospective, observational study that assessed bone variables at the tibia sites among a diverse population of individuals with chronic SCI (n=70). Peripheral quantitative computed tomography scans were taken at the 4% (distal tibia) and 38% (diaphyseal tibia) tibia site by measuring from the distal to proximal tibia starting at the inferior border of the medial malleolus. Study 2 was a review of systematic reviews exploring the effect of RT on health outcomes among community dwelling healthy adults (total of 11 systematic reviews, representing 364 primary studies and 382,627 unique participants). Study 3 was a qualitative study involving a multimethod approach. Interviews were conducted with people who have chronic health conditions and had an AE as a result of RT (n=12), and researchers who published RT studies (n=14). Interview data were analyzed using the thematic framework method. AE-reporting recommendations were generated based on interview data and were turned into an electronic survey to perform a modified Delphi consensus process involving 19 international researchers who published RT studies.
Results: Study 1 demonstrated no changes in trabecular bone (trabecular volumetric BMD at the 4% tibia site), but reported a decline in cortical bone (cortical volumetric BMD, cortical thickness and cross-sectional area at the 38% tibia site) in people with a chronic SCI. Study 2 showed that RT was associated with a reduction in all-cause mortality and cardiovascular disease incidence, and an improvement in physical functioning. However, AEs were not being consistently monitored or reported in RT studies. For study 3, we learned that despite participant awareness of the value and benefits of RT, there is concern about experiencing exercise-related AEs. Furthermore, the perceived risks of RT influenced the participants’ decision to engage or return to RT. Within the exercise community, there is suboptimal implementation of existing AE reporting standards, or the perception that the available guidelines do not apply to exercise trials. The barriers identified were that researchers lack guidance, resources, or motivation for rigorous AE reporting. To facilitate AE reporting, researchers educate and value participants, use trained personnel, and implement standardized guidelines. An exercise-specific AE-reporting toolkit (i.e., checklist, template form, and decision tree) was developed based on the consensus results (3 rounds; minimum 74% agreement on each recommendation).
Results: Based on the results of study 1, people with a chronic SCI could continue to benefit from exercise interventions to prevent loss in bone mass. The findings of study 2 demonstrated that although RT has health benefits, there needs to be consistency in AE reporting across studies to determine the harms of RT. For study 3, the purpose of the exercise-specific AE-reporting toolkit along with dissemination and implementation strategies is to improve AE reporting in RT studies. Accurate AE reporting will allow people with common health conditions, researchers, and health care providers to make evidence-based decisions as to whether the benefits of RT truly outweigh the harms.