Retrospective investigation of cross-sectional data.
To define the prevalence and determinants of preoperative vitamin D deficiency
among adults undergoing spinal fusion.
Summary of Background Data.
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.
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.
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
< 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
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.