Low Vitamin D, Stress Fractures Often Go Together
Written by Editor   
Wednesday, January 27, 2016 12:00 AM

Vitamin D serum levels of less than 40 ng/mL seem to be directly associated with stress fracture.  Bringing serum levels to 40 - 80 ng/mL through 50,000 IU of vitamin D2 or vitamin D3 once a week for 8 weeks or 6000 IU daily through supplementation is a suggested therapy.

Active adults with serum vitamin D values under 40 ng/mL had an elevated risk for stress fractures regardless of their age, according to a study.  The study was small, with just 53 patients who had serum 25(OH)D concentrations measured within 3 months of having a stress fracture, but roughly half had vitamin D levels that qualified as insufficient or deficient under standards recommended by The Endocrine Society, and more than four out of five had non-optimal vitamin D levels under standards set by the Vitamin D Council, which considers a serum 25(OH)D range of 40 to 80 ng/mL to be sufficient.

While the authors acknowledge that larger, prospective studies are needed to determine if vitamin D supplementation reduces stress fracture risk, they also  believe clinicians should consider testing their active adult patients to determine their vitamin D status, especially if they have had a stress fracture.

"The reality is, [the stress fracture] isn't normal. The body should be able to handle [an appropriate] level of stress, and build bone in response to that stress,” the author said.  He added that maintaining a serum vitamin D level of at least 40 ng/mL may help people who regularly participate in high-impact activities avoid stress fractures.

A recently published review suggested an association between low serum 25(OH)D levels and lower extremity stress fractures in military personnel. In a 2008 randomized trial involving female navy recruits, vitamin D-calcium supplementation appeared to significantly lower stress fracture risk.

The authors recommend a serum 25(OH)D of ≥40 ng/mL for stress fracture prophylaxis in active patients with a high functional demand.

But they noted that 16.9% of the patients in the study had serum 25(OH)D levels above 40 ng/mL, "indicating that vitamin D is not the sole predictor in the occurrence of a stress fracture."

The Endocrine Society recommends supplementation with 50,000 IU of vitamin D2 or vitamin D3 once a week for 8 weeks or 6000 IU daily in adults with 25(OH)D levels under 30 ng/mL to raise levels above this threshold.

Source:  http://www.medpagetoday.com/Endocrinology/Osteoporosis/55264