One leg standing time predicts fracture risk in older women independent of clinical risk factors and BMD.

ABSTRACT

In women of ages 75-80 years, a low one leg standing time (OLST) was associated with an increased risk of incident fractures, independently of bone mineral density and clinical risk factors. OLST contributed substantially to fracture probability, indicating that the test should be considered when evaluating fracture risk in older women. INTRODUCTION: Physical function and risk of falls are important risk factors for fracture. A few previous studies have suggested that a one leg standing time (OLST) less than 10 s predicts fracture risk, but the impact of OLST, in addition to known clinical risk factors, for fracture probability is unknown. The aim of this study was to determine the independent contribution of OLST to fracture probability in older women. METHODS: The Sahlgrenska University Hospital Prospective Evaluation of Risk of Bone Fractures (SUPERB) is a prospective population-based study of 3028 women 75-80 years old, recruited from the greater Gothenburg area in Sweden. At baseline, information on risk factors was collected using questionnaires, bone mineral density was measured with dual-energy X-ray absorptiometry (DXA), and OLST was performed. RESULTS: During a median follow-up of 3.6 years (IQR 1.5 years), X-ray-verified incident fractures were identified using health records. OLST was available in 2405 women. OLST less than 10 s was associated with an increased risk for incident hip fracture (Hazard Ratio (HR) 3.02, 95% Confidence Interval (CI) [1.49-6.10]), major osteoporotic fracture (HR 95% CI 1.76 [1.34-1.46]), and nonvertebral fracture (HR 95% CI 1.61 [1.26-2.05]) in Cox regression analyses adjusted for age, height, and weight. Depending on BMD, the 4-year fracture probability increased by a factor of 1.3 to 1.5 in a 75-year-old woman with a low OLST (<10 s). CONCLUSION: A low OLST has a substantial impact on fracture probability and should be considered when evaluating fracture risk in older women.