Incidence of Vitamin D Deficiency and Insufficiency in Those with Hip Fractures: A Prospective Cohort Study

Introduction As the rise in the population over the age of 65 years continues, there is a concern that there will be an increase in fragility hip fractures. Inadequate vitamin D levels could affect the health of the bone, and subsequently increase of sustaining a hip fracture. The purpose of our study was to determine if there was in fact an association between insufficient or deficient vitamin D levels and sustaining a hip fracture in our patients 90 years of age or older. Methods 25-hydroxy vitamin D levels in all patients who presented to the Emergency Department of a high-volume teaching institution who also had a diagnosis of hip fracture from 2017 to 2019 were prospectively and randomly assessed. Vitamin D levels were randomly ordered and assessed by the on-call orthopedic resident on all patients over 90 years of age. Overall, 47 patients that were 90 years of age or older were treated in our institution of which the study cohort consisted of 47 patients. This included 7 men and 40 women with a mean age of 94 years (range, 90 to 102 years). The guidelines of the Endocrine Society definitions of Vitamin D deficiency, insufficiency, and normal levels were used. The incidence of vitamin D deficiency and insufficiency was compared to those with normal levels for statistical significance. Outcomes were further sub-stratified by gender. Results The cohort had mean Vitamin D levels of 27.2 ng/ml (range, 4.3 to 69.4 ng/mL). Sixty-four percent of patients had lower than normal Vitamin D levels (p = 0.007) with 43% (n = 20) who were deficient and 21% (n = 10) who were considered insufficient. When outcomes were stratified by gender, men and women had similar mean vitamin D levels (p = 0.67). Women with hip fractures had higher incidences of vitamin D levels of <30 ng/mL (p = 0.002) while men had similar incidences (p = 0.6) of vitamin D levels above and below 30 ng/mL. Discussion We found an association between the incidence of hip fractures and increased incidence of insufficient or deficient levels of vitamin D those over 90 years of age. Future studies should examine how improvements in vitamin D levels can reduce potential risk of fragility hip fractures.