title: Preoperative vitamin D status of adults undergoing surgical spinal fusion.
abstract: METHODS
  Retrospective investigation of cross-sectional data.
  
  
  OBJECTIVE
  To define the prevalence and determinants of preoperative vitamin D deficiency among adults undergoing spinal fusion.
  
  
  BACKGROUND
  Vitamin D plays a critical role in establishing optimal bone health, which, in turn, is vital to the success of spinal arthrodesis. Recently, hypovitaminosis D was documented in 43% of adults undergoing any orthopedic surgery.
  
  
  METHODS
  Serum 25-hydroxyvitamin D levels were routinely measured in adults undergoing spinal fusion at a single institution. Between January 2010 and March 2011, 313 patients were retrospectively identified for inclusion. Risk factors for vitamin D deficiency (<20 ng/mL) were analyzed using univariate analysis and multivariate logistic regression.
  
  
  RESULTS
  The rates of inadequacy (<30 ng/mL) and deficiency were 57% and 27%, respectively. Although 260 patients were diagnosed with degenerative disease (spondylosis), 99 had deformity, and there were 73 revision cases. There was a higher rate of smoking (P = 0.03) and lower age (P < 0.01) in the vitamin D-deficient subset. There was no sex difference. Increasing body mass index (P < 0.01), increasing Neck and Oswestry Disability Index scores (P = 0.03), and lack of vitamin D and/or multivitamin supplementation (P < 0.01) remained predictors of deficiency after multivariate analysis. Those with previous supplementation were older (P < 0.01) and more likely to be at least 50 years old than those without repletion (P < 0.01).
  
  
  CONCLUSIONS
  Our investigation revealed a substantially high prevalence of vitamin D abnormality in the analyzed population. Although advanced age is a well-established risk factor for hypovitaminosis, young adults undergoing fusion should not be overlooked with regard to vitamin D screening; this age bracket is less likely to have been previously supplemented. In the absence of better-recognized determinants, spinal disability indices may also be useful in identifying those with deficiency.
authors.affiliation: Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO 63110, USA.
authors.forename: Geoffrey E
authors.initials: GE
authors.lastname: Stoker
authors.forename: Jacob M
authors.initials: JM
authors.lastname: Buchowski
authors.forename: Keith H
authors.initials: KH
authors.lastname: Bridwell
authors.forename: Lawrence G
authors.initials: LG
authors.lastname: Lenke
authors.forename: K Daniel
authors.initials: KD
authors.lastname: Riew
authors.forename: Lukas P
authors.initials: LP
authors.lastname: Zebala
mesh_terms: D000328:Adult; D000368:Aged; D015897:Comorbidity; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008923:Missouri / Q000453:epidemiology; D015999:Multivariate Analysis; D057234:Preoperative Period; D015995:Prevalence; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013122:Spinal Diseases / Q000097:blood / Q000453:epidemiology / Q000601:surgery; D013123:Spinal Fusion / Q000379:methods*; D013131:Spine / Q000473:pathology / Q000601:surgery*; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology
chemical_list: D014807:Vitamin D