Multiple sclerosis (MS) is the most common demyelinating disease of the central nervous system (CNS). Factors associated with disease onset include genetic predisposition, environmental and host factors, such as nutrition. Evidence is limited on the role of nutrition in MS disease progression. This preliminary study will assess the association between disease progression and nutrient intake, particularly vitamin D. Defective CNS myelin production and maintenance characterize MS pathophysiology and clinical manifestation. Evidence suggests that cell-mediated autoimmunity is important in disease pathogenesis, specifically cytokine production. An imbalance in cytokine production is thought to play a major role in immune activation/ deactivation in MS patients. Experimental data suggest the active form of vitamin D can prevent or suppress MS progression, by impacting on cytokine production. There are no reported data on vitamin D profile in MS patients. Possibly, MS patients are genetically predisposed to develop abnormal vitamin D metabolism when coupled with environmental insult (e.g., ultraviolet exposure) or other host susceptibility factors. Nutrient intake data alone may be insufficient to evaluate vitamin D adequacy in MS patients.
The sample will be 50 MS patients (cases), characterized by clinical subtype, and 25 controls without MS. Food frequency questionnaires will measure dietary intake; serum levels of active vitamin D with be assayed, as an indication of bioavailability. Univariate and multivariate analyses will be used to evaluate associations. Vitamin D levels will be continuous and categorical (i.e., deficient/ not deficient, or quartiles). Odds ratios and confidence limits from logistic regression models will estimate the risk of disease status with specific dietary variables. Pearson's correlation coefficients will be used to assess the relationship between dietary intake and serum vitamin D. These data will help define further research to evaluate the practical implications of vitamin D as a clinical tool in optimal MS disease management and health promotion.