The impact of exercise on bone mineral density and muscular function in adults with Crohn’s disease

Abstract

Reduced bone mineral density (BMD) and muscle dysfunction are recognised secondary complications of Crohn’s disease (CD), likely to be as a result of proinflammatory cytokines, glucocorticoid usage and malnutrition. The perceived benefits of exercise has been suggested to counteract these disease-specific complications with different exercise training stimuli eliciting corresponding psychological and physiological adaptations. However, the role of exercise as a therapeutic option remains poorly understood, with few prospective trials conducted in this high-risk group. Moreover, these existing studies are significantly limited by their small sample size, methodological robustness and lack of blinded outcome assessors highlighting the need for robust clinical research. Therefore, the overarching aim of this thesis is to expand the existing body of knowledge and provide novel data on the impact of exercise on bone and muscle health in CD. Firstly, a systematic review (Chapter 3) utilising the current literature was undertaken to evaluate the evidence of the benefits and harms of exercise interventions to allow the integration of the best evidence available to inform exercise recommendations. Results identified that the benefits of exercise have not been sufficiently researched, particularly in outcomes such as immune parameters, BMD, muscular function and fatigue. However, it did demonstrate that low to moderate-intensity exercise was safe, feasible and potentially beneficial at counteracting some disease specific complications in persons with an inactive to mildly active disease. Further supporting the perceived benefits of exercise. However, the majority of interventions involved modes of exercise such as yoga or walking that are suboptimal for improving bone health. As a prelude to experimental research, Chapter 5 investigated the test-retest reliability of outcome measures grip strength, isokinetic muscular strength, muscular endurance and BMD. Test-retest reliability was excellent in all outcome measures, highlighting these methods as reliable to facilitate the assessment and effectiveness of an intervention. Chapter 6 reports the prevalence and risk factors associated with bone and muscle health in inactive to mildly active CD participants. These data strengthen the evidence base that adults with CD are at an increased risk of osteopenia or osteoporosis, in addition to identifying longer disease duration, lower physical activity habits, females and smokers as correlates of BMD. Moreover, adults with CD also showed a significantly reduced upper and lower muscular endurance and lower muscular strength when matched to healthy controls. These findings informed the design of Chapter 7. This two arm, parallel-group, assessor-blind randomised controlled trial explored the effects of a 6-month combined impact and resistance home-based exercise intervention on primary outcomes BMD and muscular function. This study provided novel findings, identifying significant improvements between groups in lower and upper muscular endurance and strength, handgrip strength and BMD at the lumbar spine and femoral neck. In view of these results, a combined impact and resistance training programme is a potent stimulator for skeletal growth, structure and maintenance and should be considered as therapeutic option for the perseveration of bone and muscle parameters. Collectively, these studies provide corroborating evidence that exercise is a safe and feasible option and can be used to elicit favourable physiological and psychological changes in adults with CD.

Date of Award	7 Aug 2020
Original language	English
Awarding Institution	Northumbria University
Supervisor	Katherine Baker (Supervisor) & Garry Tew (Supervisor)