title: Prevalence of Vitamin D Deficiency in Patients Undergoing Elective Spine Surgery: A Cross-Sectional Analysis.
abstract: OBJECTIVE
  Decreased bone density secondary to osteoporosis and osteomalacia represents a significant risk factor for bony fracture and spinal instrumentation failure. We evaluated the incidence of vitamin D deficiency in patients undergoing elective spinal instrumentation to investigate which patient-level risk factors are associated with deficient vitamin D levels.
  
  
  METHODS
  Serum 25-OH vitamin D levels were evaluated postoperatively (<72 hours) in patients undergoing elective spinal fusion from 2011 through 2012. Patients >18 years with a diagnosis of degenerative spinal spondylosis or spinal instability treated with spinal fusion were included. Risk factors for vitamin D deficiency (<20 ng/mL) were analyzed using univariate and multiple logistic regression to identify independent predictors of deficiency.
  
  
  RESULTS
  The mean preoperative neck and Oswestry disability indexes of the 230 consecutive patients (mean, 57 ± 13.9 years) were 21.0 ± 9.8 and 22.2 ± 8.5, respectively. Mean 25-OH vitamin D level was 25.9 ± 12.4 ng/mL (range, 6-77 ng/mL). Sixty-nine (30.0%) patients had laboratory-confirmed vitamin D deficiency and 89 (38.9%) had laboratory-confirmed vitamin D insufficiency (20-30 ng/mL). The risk of vitamin D deficiency was greater in men (odds ratio [OR] 2.53; P = 0.009), patients aged 40-60 years (OR 2.45; P = 0.018), and those who had body mass index >40 (OR 7.55; P = 0.004), an existing diagnosis of diabetes (OR 3.29; P = 0.019), or no vitamin D supplementation (OR 4.96; P = 0.043).
  
  
  CONCLUSIONS
  Vitamin D deficiency was common in patients with degenerative spondylosis undergoing spinal fusion. Middle-aged patients, men, the morbidly obese, those with a history of diabetes, and those with no history of supplementation had a higher incidence of vitamin D deficiency.
authors.affiliation: Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah.
authors.forename: Vijay M
authors.initials: VM
authors.lastname: Ravindra
authors.affiliation: Department of Neurosurgery, Washington University in St. Louis, St. Louis, Missouri, USA.
authors.forename: Jakub
authors.initials: J
authors.lastname: Godzik
authors.affiliation: Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah.
authors.forename: Jian
authors.initials: J
authors.lastname: Guan
authors.affiliation: Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Dailey
authors.affiliation: Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah.
authors.forename: Meic H
authors.initials: MH
authors.lastname: Schmidt
authors.affiliation: Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah.
authors.forename: Erica F
authors.initials: EF
authors.lastname: Bisson
authors.affiliation: Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Hood
authors.affiliation: Department of Neurosurgery, Washington University in St. Louis, St. Louis, Missouri, USA. Electronic address: rayz@wudosis.wustl.edu.
authors.forename: Wilson Z
authors.initials: WZ
authors.lastname: Ray
mesh_terms: D015652:25-Hydroxyvitamin D 2 / Q000097:blood*; D000328:Adult; D000368:Aged; D015992:Body Mass Index; D015986:Confounding Factors, Epidemiologic; D003430:Cross-Sectional Studies; D048909:Diabetes Complications / Q000601:surgery; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D009767:Obesity, Morbid / Q000150:complications; D016017:Odds Ratio; D010024:Osteoporosis / Q000150:complications; D011237:Predictive Value of Tests; D015995:Prevalence; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013123:Spinal Fusion / Q000009:adverse effects; D055009:Spondylosis / Q000150:complications / Q000601:surgery*; D014481:United States / Q000453:epidemiology; D014808:Vitamin D Deficiency / Q000097:blood* / Q000150:complications / Q000453:epidemiology*; D014815:Vitamins / Q000097:blood*
chemical_list: D014815:Vitamins; D015652:25-Hydroxyvitamin D 2
keywords: Degenerative spondylosis; Fusion; Insufficiency; Osteoporosis; Pseudarthrosis; Spinal instrumentation; Spine; Vitamin D deficiency