title: The muscle-bone unit in children and adults with Crohn’s disease
Creators: name: Steell, Lewis
Publisher: name: University of Glasgow
Year: 2021

description: Background. Crohn’s disease (CD) is associated with multifactorial insult to the muscle-bone unit. The independent and combined effects of chronic inflammation, undernutrition, and exposure to glucocorticoids adversely affect bone and muscle mass accrual and maintenance in paediatric and adult CD, respectively. Aim. The overall aims of this thesis were to assess the muscle-bone unit in children and adults with CD and investigate the potential role for exercise to improve musculoskeletal outcomes. High-resolution MRI was used to comprehensively assess muscle-bone outcomes in paediatric and young adult with childhood onset CD managed with contemporary treatment strategies. Associations between CD and IBD with adverse musculoskeletal outcomes, in particular the risk of falls, were explored in a large population-based cohort of middle-aged and older adults using data from the UK Biobank research study. Subsequently, to explore the potential utility of exercise in CD and IBD, a systematic review was performed. Finally, the feasibility of jumping based exercise in CD was explored via an online survey followed by a short-term jumping-based exercise intervention in paediatric CD. Results. The primary results highlight persistent muscle-bone deficits in CD across different age groups, despite currently well controlled disease and contemporary management. High-resolution MRI revealed deficits in trabecular microarchitecture in paediatric but not young adult CD. Paediatric and young adult with childhood onset CD were both associated with poor muscle function, and young adults had around 20% lower muscle area, compared to healthy populations. Older adults with CD also displayed higher likelihood of pathological muscle weakness and falls compared to age-matched controls. Systematic review revealed little evidence on the utility of exercise for managing muscle-bone deficits in CD, although some studies identified a benefit of exercise to muscle function and bone mass and mild improvements in HRQoL. Particularly, the evidence for exercise in young or paediatric CD was almost non-existent. The feasibility survey suggested jumping exercise to be an acceptable and feasible intervention in adolescents and young adults with CD, with most respondents stating a willingness to exercise and intentions to participate in future exercise research. In feasibility study of jumping exercise, the recruitment rate was lower than expected from survey. Still, jumping exercise appeared feasible as the small number who participated achieved high adherence to the protocol. Conclusions. This research provides valuable insight into the muscle-bone unit in CD across different age groups. Even in well controlled disease and under contemporary management, CD remains associated with adverse musculoskeletal outcomes, including low trabecular bone volume in paediatrics and low muscle mass in young adults. Poor muscle function was characteristic in these cohorts and was linked to increased risk of falls in early old adults with CD. These data further highlight the adverse muscle-bone unit in CD and emphasise the need for effective non-pharmacological strategies to address this. Preliminary data suggests exercise to be a feasible strategy for targeting muscle-bone outcomes in CD and future research should investigate this further.