Vitamin D is hypothesized to play a role in the immunopathology and progression of multiple sclerosis (MS), yet its association with neurological disability remains uncertain, particularly in North African populations.We conducted a cross-sectional study involving 369 adult MS patients across two tertiary neurology centers in Western Libya. Serum 25-hydroxyvitamin D [25(OH)D] levels and Expanded Disability Status Scale (EDSS) scores were collected. Pearson correlation, ANOVA, and multivariable linear regression were used to assess associations between vitamin D and disability, adjusting for age, BMI, disease duration, and physical activity. Missing data and outliers were handled systematically using validated R and Python workflows.

Inclusion Criteria:

• Libyan nationals.
• aged 18 years or older.
• diagnosis of MS based on the 2017 revised McDonald criteria.
• capable of providing informed consent.
• had complete clinical, demographic, and biochemical data.

Exclusion Criteria:

• presence of other neurological disorders that could mimic MS (e.g., neuromyelitis optica spectrum disorder or Lyme disease).
• missing or incomplete medical records.
• pregnancy or lactation.
• extreme psychiatric or cognitive impairment.

Libyan male and females between 18 to 70 years diagnosed as MS