Osteoporosis is a reduction in the mass of bone per unit volme, which predisposes to the fracture of skeleton even with or without minimal trauma. So it causes a major significant problem of public health, especially in elderly. Unfortunately, it dose not usually become evident on the plain radiography until and third of skeletal mass is lost. But the development of variable methods of measuring bone mineral density (BMD) objectively has made it possible to be evaluated more accurately. Among them, the newly introduced Dual Photon Absorptiometry (DPA) allows us to measure BMD of axial skeleton nontraumatically with high accuracy and precision in clinical practice. The measurement of the spine and femur neck BMD from Jan. 1991 to Oct. 1991 in this hospital. The aim of this study is to estimate the fracture threshold and rate in osteoporosis group by comparing their BMD with that of age-matched normal control group. Following results were obtained 1) In osteoporosis group, the change of BMD with aging shows pattern of linear regresson (1l. 7% and 13.7% decrease per ten years in lumber spine and femur neck respectively). 2) In osteoporosis group, especially in the group with fracture, the rate of decrement in BMD is accelerated above the age of 55, compared to the maximal BMD value of normal korean adult. 3) It is suggested that 0.909 g/cm2 and 0.689 g/cm2 of BMD in lumbar spine and femur neck respectively, are the fracture threshold for the osteoporosis group. 4) The fracture rate is 60% or more above the age of 65 years and 50% or more below the level, 0.009 g/cm2 and 0.007g/cm2 of BMD in lumber spine and femur neck, respectively. |