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Published 3/1/2012
Jennie McKee

Studies Find Patients Have Low Levels of Vitamin D

Low levels of vitamin D may be a common problem among orthopaedic patients, according to findings of three separate studies presented at the AAOS Annual Meeting. The studies examined vitamin D levels in three types of orthopaedic patients: adults undergoing spinal fusion, postmenopausal women with distal radius fractures, and orthopaedic trauma patients.

Most experts define vitamin D insufficiency as a 25-hydroxyvitamin D (25[OH]D) level less than 32 ng/mL; vitamin D deficiency is defined as a 25(OH)D level less than 20 ng/mL.

Spinal fusion patients and vitamin D
In their study on “Preoperative Vitamin D Status of Adults Undergoing Spinal Fusion Surgery,” Jacob M. Buchowski, MD, and colleagues noted that “vitamin D plays a critical role in establishing optimal bone health, which, in turn, is vital to the success of spinal arthrodesis.” Their investigation revealed an alarmingly high rate of vitamin D abnormality in the analyzed population.

Researchers prospectively measured serum 25(OH)D levels in adults (18 years or older) who were undergoing spinal fusion at a single institution between January 2010 and March 2011. In all, 313 consecutive patients (176 females, 137 males; mean age = 55 ± 13 years) were identified for inclusion in this cross-sectional investigation. Of these, 260 patients were diagnosed with degenerative disease, 99 patients had spinal deformity, and 73 patients needed revision surgery.

Among all patients, the mean baseline 25(OH)D level was 29 ± 14 ng/mL. The investigators found a 57 percent prevalence of vitamin D inadequacy, and a 27 percent prevalence of vitamin D deficiency among study participants, although this did not seem to have an impact on bone mineral density. Patients with deficiencies were more likely to be younger than age 50 years (P < 0.050). No significant difference between men and women with regard to vitamin D deficiency was noted.

The following factors were found to be significant predictors of vitamin D deficiency:

  • higher body mass index (P = 0.003)
  • higher disability scores (P = 0.028)
  • no prior vitamin D or multivitamin supplementation (P < 0.001)

“Although advanced age is a well-established risk factor for deficiency, young adults undergoing spinal fusion should not be overlooked with regard to preoperative vitamin D screening; younger patients are less likely to have been previously supplemented,” stated Dr. Buchowski.

“Because augmenting serum 25(OH)D is straightforward and inexpensive, and hypovitaminosis-induced spinal osteoporosis and osteomalacia may predispose to poor surgical outcome, we advocate repletion for spine patients with documented deficiency,” he noted.

Vitamin D levels in postmenopausal women
A Korean study on “Hypovitaminosis D in Postmenopausal Women with a Distal Radius Fracture” investigated serum vitamin D levels in postmenopausal women.

“On average, distal radius fractures (DRFs) occur 15 years earlier than hip fractures and may be an indicator for subsequent hip or vertebral fractures,” noted the authors. “To reduce the risk of future fractures, we thought it may be appropriate to identify the risk factors for patients experiencing their first DRF.”

The study included 104 postmenopausal women who had been surgically treated for a DRF and 107 age-matched control patients without a fracture (control group).

Investigators compared serum vitamin D levels, taking into account age and seasonal variations. They measured and analyzed the following to determine if there was any association with vitamin D levels: bone mineral density (BMD), serum parathyroid hormone (PTH) levels, and several bone turnover markers, including serum osteocalcin, C-telopeptide, and urine N-telopeptide.

Results showed that the DRF group had a mean serum vitamin D level that was significantly lower than that of the control group (P < 0.001). In particular, DRF patients in their 50s and 60s had significantly lower vitamin D levels than their age-matched counterparts in the control group (P = 0.001 and 0.013, respectively), whom the authors noted “may be a good target group for prevention of future fractures.”

“When seasonal variation was considered, significant differences in serum vitamin D levels were found between the groups in autumn and winter,” they stated. “Hip BMDs were significantly lower in the DRF group than in the control group, and we found a positive correlation between serum vitamin D levels and hip BMD.” No significant differences in bone turnover markers were found, although serum PTH levels were somewhat higher among DRF patients (P = 0.08).

“Further studies are warranted to determine whether hypovitaminosis D is a risk factor for DRF and whether vitamin D supplementation helps rehabilitation and the prevention of future fractures in patients with a DRF,” they concluded.

Orthopaedic trauma patients and vitamin D
Low serum vitamin D levels “have been linked to numerous musculoskeletal and nonmusculoskeletal conditions,” noted the authors of “Incidence of Vitamin D Deficiency in Orthopaedic Trauma Patients.”

This retrospective, Institutional Review Board-approved, chart review identified patients who had 25(OH)D levels noted in their charts and were treated for a fracture. Patients younger than 18 years and those with known risk factors for vitamin D deficiency were excluded.

A total of 889 patients (487 females, 402 males; mean age, 53.8 years) treated between January 2009 and September 2010 met the inclusion criteria. The data on the patients’ vitamin D levels were available in the patients’ charts, noted the researchers, because a protocol to check vitamin D levels on acute fracture patients had been established due to concerns about vitamin D deficiency.

The overall incidence of vitamin D insufficiency was 78 percent, while the incidence of vitamin D deficiency was 39 percent. “This indicates how widespread low vitamin D is,” they said.

These findings reinforce the fact that “vitamin D insufficiency and deficiency in acute orthopaedic trauma patients are relatively common.” Researchers noted that more research is necessary to learn more about the clinical significance of this finding.

“Because vitamin D plays a vital role in bone metabolism and has been implicated in not only increasing risk of fracture, but also in ability to heal fractures, documenting the prevalence of vitamin D deficiency in a trauma patient population is of vital importance as a first step in raising awareness among orthopaedic traumatologists and further determining a screening and treatment strategy for vitamin D deficiency in the trauma patient population,” they concluded.

Coauthors with Dr. Buchowski (Globus Medical, Stryker, CoreLink, Complex Spine Group/K2M, Inc.) are Geoffrey Stoker, BS (no conflicts); Keith H. Bridwell, MD (DePuy, A Johnson & Johnson Company); Lawrence G. Lenke, MD (Medtronic, Axial Biotech, Quality Medical Publishing, and DePuy, A Johnson & Johnson Company); K.D. Riew, MD (Biomet, Medtronic Sofamor Danek, Osprey, Amedica, Benvenue, Expanding Orthopedics, Nexgen, Paradigm Spine, PSD, Spinal Kinetics, Spineology, Vertiflex); and Lukas P. Zebala, MD (DePuy, A Johnson & Johnson Company – Institutional Educational Grant).

Hyun Sik Gong, MD (no conflicts), and Cheol Ho Song, MD (no conflicts), coauthored “Hypovitaminosis D in Postmenopausal Women with a Distal Radius Fracture.”

The authors of “Incidence of Vitamin D Deficiency in Orthopaedic Trauma Patients” are Brett D. Crist, MD (Amedica Corporation, The Orthopaedic Implant Company, Medtronic, Novalign, Synthes, Wound Care Technologies, Zimmer); Michael A. Hood, MD (no conflicts); Gregory J. Della Rocca, MD, PhD (Synthes, Medtronic, Amedica, The Orthopaedic Implant Company, Wound Care Technologies); James P. Stannard, MD (KCI, Medtronic Sofamor Danek, Sonoma, Theime); David Volgas, MD (no conflicts); and Yvonne M. Murtha, MD (no conflicts).

Jennie McKee is a staff writer for AAOS Now; she can be reached at mckee@aaos.org

Bottom Line

  • According to a prospective case series, the prevalence of vitamin D inadequacy among 313 patients undergoing spinal fusion at a single institution was 57 percent; more than a quarter of patients (27 percent) were vitamin D deficient.
  • A Korean study found that women with distal radius fractures had a mean serum vitamin D level that was significantly lower than that of an age-matched control group of female patients (P < 0.001).
  • A retrospective chart review found that the overall incidence of vitamin D insufficiency among 889 patients treated for a fracture at a Level 1 trauma center was 78 percent, while the incidence of vitamin D deficiency was 39 percent.

Additional Resources
Preoperative Vitamin D Status of Adults Undergoing Spinal Fusion Surgery

Hypovitaminosis D in Postmenopausal Women with a Distal Radius Fracture

Prevalence of Vitamin D Deficiency in Orthopaedic Trauma Patients