Evaluating the Risk of a Fifth Metatarsal Stress Fracture by Measuring the Serum 25-Hydroxyvitamin D Levels

Foot Ankle Int. 2016 Mar;37(3):307-11. doi: 10.1177/1071100715617042. Epub 2015 Nov 23.


Background: The fifth metatarsal bone is a common site of stress fractures in soccer athletes. Although several endocrine risk factors for stress fractures have been proposed, the endocrine risks for fifth metatarsal (5-MT) stress fractures have not been evaluated.

Methods: To evaluate the endocrine risks of fifth metatarsal stress fractures, we conducted a cumulative case-control study. The present study included 37 athletes, of which 18 had a history of a zone 2 or zone 3 fifth metatarsal stress fracture and 19 controls. We analyzed serum 25-hydroxyvitamin D (25-OHD), serum parathyroid hormone (PTH), as well as biochemical markers of bone turnover by univariate or multivariate analyses.

Results: Logistic regression analyses adjusted for multiple confounders revealed that insufficient serum 25-OHD levels less than 30 ng/mL (odds ratio [OR], 23.3), higher serum PTH levels (OR, 1.01), or higher serum bone-specific isoform of alkaline phosphatase levels (OR, 1.10) rather than serum tartrate-resistant acid phosphatase 5b were associated with statistically significantly increased odds of 5-MT stress fractures. A postestimation calculation demonstrated that 25-OHD levels of 10 and 20 ng/mL were associated with 5.1 and 2.9 times greater odds for 5-MT stress fractures, respectively.

Conclusion: 25-OHD insufficiency was associated with an increased incidence of 5-MT stress fractures. This insight may be useful for intervening to prevent 5-MT stress fractures.

Level of evidence: Level III, case-control study.

Keywords: fifth metatarsal stress fracture; soccer athletes; vitamin D.

MeSH terms

  • Alkaline Phosphatase / blood
  • Athletes
  • Biomarkers / blood
  • Case-Control Studies
  • Fractures, Stress / blood*
  • Fractures, Stress / etiology*
  • Humans
  • Isoenzymes / blood
  • Male
  • Metatarsal Bones / injuries*
  • Parathyroid Hormone / blood
  • Risk Assessment
  • Tartrate-Resistant Acid Phosphatase / blood
  • Vitamin D / analogs & derivatives*
  • Vitamin D / blood
  • Young Adult


  • Biomarkers
  • Isoenzymes
  • Parathyroid Hormone
  • Vitamin D
  • 25-hydroxyvitamin D
  • Alkaline Phosphatase
  • Tartrate-Resistant Acid Phosphatase