Osteoporosis lowers bone density and is the main cause of falls and fractures. The aim of this study was to clarify the following three points by focusing on bone density and the lower limb muscle strength and to do so with the view to prevent both osteoporosis and falls. (1) The changes in bone density and the lower limb muscle strength brought on by age. (2) The consequences on bone density and the lower limb muscle strength brought on by menopause which affected the changes in bone density. (3) The examination of the prediction factors of the decline of bone density. There were 257 females (34 to 70 years) who had received the medical screening for osteoporosis. The lower limb muscle strength was determined by measuring the abductor muscle strength of the hip joint. To determine bone density was measured the bone density of the lumbar vertebrae by applying the DXA method. Our results indicated the following facts:With age, bone density and the knee gap force declined by approximately 20%. The changes brought on by menopause lowered bone density by 20% within ten years after menopause. The age group who were ten years after menopause indicated that the beginning of the decline of the lower limb muscle strength, which accompanied the decline in bone density, corresponded to age 55 and older. The results of the multiple regression analysis, which was conducted for the purpose of extracting the prediction factors for bone density, identified three such factors:Body weight, the presence or absence of underlying disease and the risk potential of the knee gap force (10 kgf) for falls. Our results further indicated that the abductor muscle strength of the hip joint was related to the bone density of the lumbar vertebrae. The results also indicated that the fact that the lower limb muscle strength was also closely related to falls suggested the possibility that maintaining the abductor muscle strength of the hip joint above 10 kgf would be effective in preventing osteoporosis-related falls and fractures.
