title: Association of vitamin D deficiency with RNFL thickness in MS individuals without history of optic neuritis.
abstract: Vitamin D deficiency has been associated with both increased risk and severity of Multiple Sclerosis (MS) as it has a modulating effect on the immune process that causes inflammation/demyelination and axonal damage. Optical Coherence Tomography (OCT) offers a quick, reliable and non-invasive way to assess the Retinal Nerve Fiber Layer (RNFL) and identifies axonal loss generated by either direct inflammation or from neurodegeneration.
  
  
  OBJECTIVE
  To determine the association of vitamin D and RNFL in MS patients without a history of Optic Neuritis (ON) by comparing RNFL thickness in patients that are vitamin D deficient with those having normal serum levels.
  
  
  METHODS
  The cohort of 76 MS patients underwent OCT testing to assess the RNFL thickness and macular volume, and measurement of serum 25-OH Vitamin D level. Vitamin D deficiency was defined as <30ng/ml and sufficiency as ≥30ng/ml.
  
  
  RESULTS
  A total of 131 eyes were divided in two groups: vitamin D deficient (n=86 eyes, mean=17.7ng/ml) and vitamin D sufficient (n=45 eyes, mean=40.3ng/ml). Twenty one eyes had previous ON and were excluded from this analysis. Vitamin D deficiency was identified in 66% of the participants. RNFL thickness was similar for the vitamin D deficient and sufficient groups (85.5 vs 86μm respectively, p=0.89). Significant differences were present for age with the deficient group being younger (42 years vs 51 years, p=0.005) and having shorter disease duration (7.5 years vs 11.4 years, p=0.006).
  
  
  CONCLUSIONS
  Vitamin D deficiency is not associated with thinning of RNFL or macular volume in MS eyes unaffected by ON. This finding suggests the role of vitamin D in modulating the severity of MS is not exerted through an influence on neurodegeneration.
authors: OMRF Multiple Sclerosis Center of Excellence, 820 NE 15th Street, Oklahoma City, OK 73104, USA. Electronic address: Cecilie-Fjeldstad@omrf.org.
authors: Cecilie
authors: C
authors: Fjeldstad
authors: Department of Neurology, University of Utah, Imaging & Neurosciences Center at Research Park, 729 Arapeen Drive Rm 1172, Salt Lake City, UT 84108, USA. Electronic address: a.fjeldstad@utah.edu.
authors: Anette S
authors: AS
authors: Fjeldstad
authors: Department of Health, Sport, and Exercise Sciences, 1301 Sunnyside Avenue, Robinson center 104D, University of Kansas, Lawrence, KS 66045, USA. Electronic address: joseph.weir@ku.edu.
authors: Joseph P
authors: JP
authors: Weir
authors: OMRF Multiple Sclerosis Center of Excellence, 820 NE 15th Street, Oklahoma City, OK 73104, USA.
authors: Gabriel
authors: G
authors: Pardo
keywords: Multiple sclerosis; Optic neuritis; Optical coherence tomography; Retinal nerve fiber layer; Vitamin D