Vitamin D, race, and excessive daytime sleepiness

J Clin Sleep Med. 2012 Dec 15;8(6):693-7. doi: 10.5664/jcsm.2266.

Abstract

Study objectives: First, to determine whether serum vitamin D levels were correlated with excessive daytime sleepiness (EDS) in patients with or without vitamin D deficiency (VitDd). Second, to assess whether race affected the relation between vitamin D levels and EDS.

Methods: Serum 25-hydroxyvitamin D (25OHD) was measured by immunoassay in a consecutive series of 81 sleep clinic patients who complained of sleep problems and nonspecific pain (25OHD < 20 ng/mL ' VitDd). Sleepiness was determined using the Epworth Sleepiness Scale score ([ESSs] ESSs ≥ 10 ≡ EDS). Correlations were assessed using Pearson r.

Results: In patients without VitDd (25OHD ≥ 20 ng/mL), ESSs was inversely correlated with vitamin D concentration (r = 0.45, p < 0.05). The group consisted of 6% black patients, compared with 35% for the entire cohort. Among the patients who had VitDd (25OHD < 20 ng/mL), ESSs was directly correlated with 25OHD in black (r = 0.48, p < 0.05) but not white patients. In black patients, mean ESSs in patients with VitDd were higher and 25OHD levels were lower p < 0.05).

Conclusions: The results suggested the novel possibility that VitDd-related disease has a yet-to-be-identified mechanistic role in the presentation of sleepiness, sleep disorders, or both. Further research is needed to clarify the mechanism(s) involved in producing the complex relationships noted.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers
  • Black or African American*
  • Case-Control Studies
  • Comorbidity
  • Disorders of Excessive Somnolence / ethnology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • United States / epidemiology
  • Vitamin D / analogs & derivatives
  • Vitamin D / blood
  • Vitamin D Deficiency / ethnology*

Substances

  • Biomarkers
  • Vitamin D
  • 25-hydroxyvitamin D