رسالة جامعية
The Role of Vitamin D in Inflammatory Bowel Disease Pathogenesis and Severity
| العنوان: | The Role of Vitamin D in Inflammatory Bowel Disease Pathogenesis and Severity |
|---|---|
| المؤلفون: | Limketkai, Berkeley Nguyen |
| المساهمون: | Tonascia, James A, Brant, Steven R, Hendrix, Craig W, Adkinson, N. Franklin |
| بيانات النشر: | Johns Hopkins University USA |
| سنة النشر: | 2017 |
| المجموعة: | Johns Hopkins University, Baltimore: JScholarship |
| مصطلحات موضوعية: | inflammatory bowel disease, Crohn's disease, ulcerative colitis, vitamin D |
| الوصف: | Vitamin D has traditionally been known for its role in bone metabolism, but more recently been implicated in immune function. Emerging evidence has further suggested that vitamin D may be involved in inflammatory bowel disease (IBD) pathogenesis and activity. Studies found lower vitamin D levels among IBD patients, particularly in the setting of increased disease activity, implying that vitamin D influenced IBD. However, interpretation of these findings is challenged by the concept of reverse causation, where intestinal inflammation is already known to reduce vitamin D levels. These studies have therefore not established vitamin D deficiency as a cause or effect of IBD in humans. The principal objective of this thesis was to clarify the causal role of vitamin D in IBD pathogenesis and severity, while employing diverse methodologic approaches to overcome the issue of reverse causation. The first study was a case-control comparison of vitamin D levels from sera that were prospectively collected before and around the time of diagnosis of Crohn’s disease (CD). This longitudinal analysis permitted the evaluation of vitamin D levels as precursors to CD pathogenesis, while reducing interference by reverse causation. Vitamin D levels were similar between cases and controls prior to diagnosis, but significantly lower among cases around the time of diagnosis. The second study was an ecologic study that evaluated the association of ultraviolet (UV) exposure – a surrogate marker of vitamin D that was not influenced by IBD – and IBD hospitalization severity. Low UV exposures were associated with increased rates of hospitalization, prolonged hospitalization, and need for bowel surgeries. The third study was a systematic review of randomized trials that evaluated the effect of vitamin D supplementation on IBD activity. Randomization in these trials would have theoretically permitted assessment of the effect of vitamin D on IBD independent of disease activity. The meta-analysis of 4 studies with 12-month follow-up showed a ... |
| نوع الوثيقة: | thesis |
| وصف الملف: | application/pdf |
| اللغة: | English |
| العلاقة: | http://jhir.library.jhu.edu/handle/1774.2/60795Test |
| الإتاحة: | http://jhir.library.jhu.edu/handle/1774.2/60795Test |
| رقم الانضمام: | edsbas.FA1AC550 |
| قاعدة البيانات: | BASE |
| الوصف غير متاح. |