title: Interdependence and contributions of sun exposure and vitamin D to MRI measures in multiple sclerosis.
abstract: OBJECTIVE
  To assess the relationships of sun exposure history, supplementation and environmental factors to vitamin D levels in multiple sclerosis (MS) patients and to evaluate the associations between sun exposure and MRI measures.
  
  
  METHODS
  This study included 264 MS patients (mean age 46.9±10 years, disease duration 14.6±10 years; 67.8% relapsing-remitting, 28% secondary progressive and 4.2% primary progressive MS) and 69 healthy controls. Subjects underwent neurological and 3 T MRI examinations, provided blood samples and answered questions to a structured questionnaire. Information on race, skin and eye colour, supplement use, body mass index (BMI) and sun exposure was obtained by questionnaire. The vitamin D metabolites (25-hydroxy vitamin D3, 1, 25-dihydroxy vitamin D3 and 24, 25-dihydroxy vitamin D3) were measured using mass spectrometry.
  
  
  RESULTS
  Multivitamin supplementation (partial correlation r(p)=0.29, p<0.001), BMI (r(p)=-0.24, p=0.001), summer sun exposure (r(p)=0.22, p=0.002) and darker eye colour (r(p)=-0.18, p=0.015) had the strongest associations with vitamin D metabolite levels in the MS group. Increased summer sun exposure was associated with increased grey matter volume (GMV, r(p)=0.16, p=0.019) and whole brain volume (WBV, r(p)=0.20, p=0.004) after correcting for Extended Disability Status Scale in the MS group. Inclusion of 25-hydroxy vitamin D3 levels did not substantially affect the positive associations of sun exposure with WBV (r(p)=0.18, p=0.003) and GMV (r(p)=0.14, p=0.026) in the MS group.
  
  
  CONCLUSIONS
  Sun exposure may have direct effects on MRI measures of neurodegeneration in MS, independently of vitamin D.
authors: Department of Neurology, Buffalo Neuroimaging Analysis Center, State University of New York, Buffalo, NY, USA.
authors: Robert
authors: R
authors: Zivadinov
authors: Cierra N
authors: CN
authors: Treu
authors: Bianca
authors: B
authors: Weinstock-Guttman
authors: Caitlin
authors: C
authors: Turner
authors: Niels
authors: N
authors: Bergsland
authors: Kerri
authors: K
authors: O'Connor
authors: Michael G
authors: MG
authors: Dwyer
authors: Ellen
authors: E
authors: Carl
authors: Deepa P
authors: DP
authors: Ramasamy
authors: Jun
authors: J
authors: Qu
authors: Murali
authors: M
authors: Ramanathan
mesh_terms: D015650:24,25-Dihydroxyvitamin D 3 / Q000097:blood; D000328:Adult; D001921:Brain / Q000473:pathology; D002112:Calcifediol / Q000097:blood; D002117:Calcitriol / Q000097:blood; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D020528:Multiple Sclerosis, Chronic Progressive / Q000097:blood / Q000175:diagnosis*; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000097:blood / Q000175:diagnosis*; D009929:Organ Size / Q000502:physiology; D013223:Statistics as Topic; D013472:Sunlight; D014807:Vitamin D / Q000008:administration & dosage* / Q000097:blood*
chemical_list: D014807:Vitamin D; D015650:24,25-Dihydroxyvitamin D 3; D002117:Calcitriol; D002112:Calcifediol
keywords: MRI; Multiple Sclerosis