Association between bone mass as assessed by quantitative ultrasound and physical function in elderly women: The Fujiwara-kyo study

OBJECTIVES: This study aimed to investigate differences in physical function by bone mass category as assessed by speed of sound, and the association between bone mass and physical function in Japanese elderly women. METHODS: Participants (≥65 years, n = 954) were divided into the osteoporosis, osteopenia, and normal groups based on speed of sound values, and physical function parameters were compared among groups. In addition, the predictive ability of physical function for low bone mass was determined by area under the curve analysis. Data were collected in 4 cities in Nara, Japan, in 2007 or 2008. RESULTS: All physical functions were significantly lower in the osteoporotic group than in the normal group. Lower bone mass was associated with poor muscle strength and physical function after adjusting for age, height and weight. In addition, one-leg standing time and 10-m gait time were predictive of low bone mass (osteopenia and osteoporosis levels, respectively). Elderly women with low physical function, especially those with a short one-leg standing time, should be suspected of having decreased bone mass. CONCLUSIONS: Measurements of physical function can effectively identify elderly women with low bone mass at an early stage without the need for bone mass measurements. In particular, one-leg standing time and 10-m gait time were good predictors of low bone mass, and is easy to measure, low-cost, and can be self-measured. These findings will be helpful in the prevention and treatment of osteoporosis.