Vitamin D deficiency in type 1 narcolepsy: a reappraisal.
Narcolepsy type 1 (NT1) is considered to be an immune-mediated disease in which environmental factors, such as vitamin D, might play a major role. The association between NT1 and vitamin D deficiency has previously been reported. The aim of this case-control study was to reassess vitamin D levels in a large clinic-based adult and paediatric population of patients with NT1 by considering several potential confounding factors.



The serum level of 25-hydroxyvitamin D (25OHD) was measured in 174 Caucasian patients with NT1 and 174 controls. Demographic and clinical features, body mass index (BMI), Pandemrix® vaccination, age, and season at the time of blood sampling were recorded. Between-group comparisons were made using univariate and multivariate logistic regression analyses. When appropriate, interaction terms were tested using the Wald Chi-squared test.



Age, BMI, and season of blood sampling were different between groups. Conversely, the 25OHD level and fraction of subjects with vitamin D deficiency (serum level <75 nmol/L: 46.6% of patients vs 48.3% of controls; <50 nmol/L: 20.7% vs 17.2%) did not differ between patients with NT1 and controls. Overall, vitamin D deficiency was more frequent in men, obese subjects, and in samples collected in winter, without any association with NT1. In the patients group, no significant association was found between vitamin D deficiency, NT1 duration and severity, treatment, and Pandemrix® vaccination.



Vitamin D levels were not associated with NT1 in a large case-control population when potential demographic and clinical confounding factors were taken into account.
Department of Neurology, National Reference Network for Narcolepsy, CHU Montpellier, Hôpital Gui-de-Chauliac, France; INSERM U1061, University of Montpellier 1, Montpellier, France. Electronic address: ydauvilliers@yahoo.fr.
Yves
Y
Dauvilliers
Department of Neurology, National Reference Network for Narcolepsy, CHU Montpellier, Hôpital Gui-de-Chauliac, France.
Elisa
E
Evangelista
Department of Neurology, National Reference Network for Narcolepsy, CHU Montpellier, Hôpital Gui-de-Chauliac, France; INSERM U1061, University of Montpellier 1, Montpellier, France.
Regis
R
Lopez
Department of Neurology, National Reference Network for Narcolepsy, CHU Montpellier, Hôpital Gui-de-Chauliac, France; INSERM U1061, University of Montpellier 1, Montpellier, France.
Lucie
L
Barateau
Department of Neurology, National Reference Network for Narcolepsy, CHU Montpellier, Hôpital Gui-de-Chauliac, France.
Sabine
S
Scholz
Laboratoire de Biochimie-Hormonologie, CHU Montpellier, Hôpital Lapeyronie, France.
Barbara
B
Crastes de Paulet
Department of Neurology, National Reference Network for Narcolepsy, CHU Montpellier, Hôpital Gui-de-Chauliac, France.
Bertrand
B
Carlander
INSERM U1061, University of Montpellier 1, Montpellier, France.
Isabelle
I
Jaussent
D000328:Adult; D000367:Age Factors; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D009290:Narcolepsy / Q000097:blood / Q000150:complications*; D012621:Seasons; D012737:Sex Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood*; D044465:White People
D014807:Vitamin D; C104450:25-hydroxyvitamin D
Autoimmunity; Hypocretin/orexin; Narcolepsy; Sleepiness; Vaccination; Vitamin D