title: Low vitamin D in narcolepsy with cataplexy.
abstract: BACKGROUND
  Narcolepsy with cataplexy (NC) is currently thought to be an autoimmune-mediated disorder in which environmental risk factors make a significant contribution to its development. It was proposed that vitamin D deficiency plays a role in autoimmune diseases. Here we investigated whether NC can be associated with 25-hydroxyvitamin D (25(OH)D) level deficiency in patients with NC compared with gender- and age-matched normal controls.
  
  
  METHODS
  Serum level of 25 (OH)D was determined in 51 European patients with typical NC compared to 55 age-, gender-, and ethnicity-matched healthy controls. Demographic and clinical data (age at onset, duration and severity of disease at baseline, and treatment intake at time of study) and season of blood sampling were collected to control for confounding variables.
  
  
  RESULTS
  Serum 25(OH)D concentration was lower in NC compared to controls (median, 59.45 nmol/l [extreme values 24.05-124.03] vs. 74.73 nmol/l [26.88-167.48] p = 0.0039). Patients with NC had significantly greater vitamin D deficiency (<75 nmol/l) than controls (72.5% vs 50.9%, p = 0.0238). Division into quartiles of the whole sample revealed that the risk of being affected with NC increased with lower 25(OH)D level, with a 5.34 OR [1.65-17.27] for the lowest quartile (p = 0.0051). Further adjustment for BMI did not modify the strength of the association (OR: 3.63, 95% CI = 1.06-12.46, p = 0.0191). No between BMI and 25(OH)D interaction, and no correlation between 25(OH)D level and disease duration or severity or treatment intake were found in NC.
  
  
  CONCLUSIONS
  We found a higher frequency of vitamin D deficiency in NC. Further studies are needed to assess the contribution of hypovitaminosis D to the risk of developing narcolepsy, and to focus on the utility of assessing vitamin D status to correct potential deficiency.
authors.affiliation: Department of Neurology, Hôpital Gui-de-Chauliac, CHU Montpellier, Montpellier, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Carlander
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Puech-Cathala
authors.forename: Isabelle
authors.initials: I
authors.lastname: Jaussent
authors.forename: Sabine
authors.initials: S
authors.lastname: Scholz
authors.forename: Sophie
authors.initials: S
authors.lastname: Bayard
authors.forename: Valérie
authors.initials: V
authors.lastname: Cochen
authors.forename: Yves
authors.initials: Y
authors.lastname: Dauvilliers
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002385:Cataplexy / Q000097:blood* / Q000150:complications / Q000208:ethnology; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009290:Narcolepsy / Q000097:blood* / Q000150:complications / Q000208:ethnology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood*; D044465:White People; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D