Item – Theses Canada

​
OCLC number
1033222863
Link(s) to full text
LAC copy
LAC copy
Author
Hanwell, Heather.
Title
Vitamin D Status and its Contribution to Multiple Sclerosis Risk : Insights Gained through the Study of Children with Central Nervous System Demyelination.
Degree
Ph. D. -- University of Toronto, 2012
Publisher
Toronto : University of Toronto, 2012.
Description
1 online resource
Notes
Includes bibliographical references.
Abstract
Acute demyelination in children may be a monophasic illness or the sentinel attack of multiple sclerosis (MS) - a chronic inflammatory neurodegenerative demyelinating disease. MS risk is largely determined during childhood and vitamin D may protect against MS. The primary objective of this thesis was to evaluate vitamin D status in children presenting with acute demyelinating syndromes (ADS) as a potential contributor to MS outcome. The LIAISON "25 OH Vitamin D TOTAL" assay was validated to assess the biomarker of vitamin D status - serum 25-hydroxyvitamin D (25(OH)D) concentrations. Consecutive patients (<16 y) were enrolled at presentation with ADS and prospectively evaluated at 23 Canadian centres. MS was defined by a second clinical demyelinating event or by MRI evidence of new lesions over time. Cox proportional hazards regression models assessed risk of MS outcome as a function of serum 25(OH)D tertiles, accounting for factors associated with either MS risk or vitamin D status - age, sex, season, and HLA-DRB1*15 status. Of 211 children with 25(OH)D measured in sera obtained a median of 9 days from onset (interquartile range, 5 - 17 d; maximum 36 days), 20% (n = 41) were diagnosed with MS after 3.7 mos. (3.1 - 7.3 mos.). Risk of MS was lower in children with 25(OH)D levels in the highest tertile (≥ 74 nmol/L) at ADS versus those in the lowest tertile (<50 nmol/L) (HR 0.41; 95% CI 0.18 to 0.97, adjusted model). Children with higher circulating 25(OH)D concentrations at ADS have a lower risk of MS. Further evidence for a role of vitamin D insufficiency during childhood and adolescence contributing to MS risk comes from three MS patients with suboptimally managed pseudo-vitamin D deficiency rickets. Finally, a sun exposure questionnaire was validated in the latter part of this thesis for use in future research into determinants of vitamin D status and their association with risk of MS.
Other link(s)
hdl.handle.net
tspace.library.utoronto.ca
Subject
Vitamin D.
Multiple Sclerosis.
Nutrition.
Pediatric.
Autoimmune.
Cholecalciferol.
Calciferol.
Bradford Hill.
Sun exposure.
Questionnaire.
UVB.
0570.
0317.
0566.