- Title
- An investigation into relationships among neural, vascular and osseous factors in the diabetic foot
- Creator
- Barwick, Alex Louise
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2016
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- The social and financial cost of diabetes and associated lower limb complications is increasing markedly. Interaction between neurological and vascular dysfunction in diabetes are thought to influence bone in the periphery, predisposing to pathology such as Charcot foot, a rare but debilitating joint disease. However, there is a lack of conclusive evidence relating neurological and vascular function to peripheral bone health in people with diabetes. This thesis presents an investigation into relationships among neuropathy, vascular dysfunction and foot bone health in those with diabetes. Such information is useful in the prevention, diagnosis and management of lower limb complications of diabetes. The research is designed to address two central hypotheses: That those with diabetic neuropathy have altered vascular reactivity in the feet. ; That neuropathy induced vascular changes in those with diabetes, contribute to a reduction in bone mineral density in the feet. The research includes, firstly, a systematic review of current research related to foot bone strength in people with diabetic neuropathies with a meta-analysis of obtained data. Inconsistent findings were observed among the ten included studies and the meta-analysis was equivocal. Furthermore, the literature was limited by methodological quality and gaps within the literature were observed including the lack of data on foot bones other than the calcaneus prompting the need for further research. Secondly, two studies developing methodologies required for the research were performed. A reliability study of techniques for assessing post-occlusive reactive hyperaemia at the hallux as a measure of microvascular function was performed. The study found that its measurement in the hallux, using laser Doppler with a probe heated to thermoneutral, is a reliable method of measuring microvascular function for use in research. The most reliable parameters were peak as a percentage of baseline and the index of the area under the curve post-occlusion to pre-occlusion. A reliability study of computed tomography derived densitometry of all tarsal and metatarsal bones was also performed. The study found that foot bone density can be reliably measured in the tarsals and metatarsals using averaged regions of interest on computed tomography scans. Trabecular bone density was more reliably derived than that of cortical bone. These two methodologies, measurement of post-occlusive reactive hyperaemia at the hallux and bone density measurement in the foot, were used in the final two studies addressing the central hypotheses. A cross-sectional study was performed to test the hypothesis that those with diabetic neuropathy have altered vascular reactivity in the feet. This approach was taken to examine the complex relationships among diabetic neuropathy types and vascular reactivity in a clinically relevant population, accounting for important confounders in the design and statistical analyses. The study found that the presence of sensory neuropathy was predictive of a slower time to peak perfusion following occlusion. Finally, a cross-sectional case-control study was performed to test the hypothesis that neuropathy induced vascular changes in those with diabetes, contribute to a reduction in bone mineral density in the feet. The study compares the foot bone density of those with diabetic neuropathy with a diabetes control group. No clear association was demonstrated. Additional analyses were performed to observe potential relationships between subtype of neuropathy and foot bone density, and microvascular dysfunction and foot bone density. No relationships were observed. These results, limited by the cross-sectional design of the studies, suggest that whilst peripheral neuropathy is associated with altered microvascular function, this may not have an impact on foot bone density in a manner that predisposes to pathology.
- Subject
- diabetic feet; lower limb complications; diabetes; Charcot foot; vascular dysfunction; foot bone health; thesis by publication
- Identifier
- http://hdl.handle.net/1959.13/1314964
- Identifier
- uon:22867
- Rights
- Copyright 2016 Alex Louise Barwick
- Language
- eng
- Full Text
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | ATTACHMENT01 | Thesis | 3 MB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Abstract | 111 KB | Adobe Acrobat PDF | View Details Download |