Non-invasive techniques for the measurement of bone mineral

Non-invasive, safe and precise techniques for measuring bone mineral density are available and have an important role in the detection, prevention and treatment of bone loss associated with aging, menopause and many illnesses affecting women and men. The three most widely accessible and established techniques for measuring regional bone mineral density are single and dual photon absorptiometry and quantitative computed tomography. A technique of greater accuracy, dual energy X-ray absorptiometry, has only recently become available. These techniques have made it possible to measure the magnitude, time course and regional specificity of the skeleton's response to ageing, menopause and illness. A better understanding of the clinical epidemiology of fractures and the mechanisms responsible for bone loss has been obtained. Practical information has been obtained about the dose, duration and efficacy of oestrogen replacement therapy in preventing perimenopausal bone loss and the benefits and limitations of different forms of exercise on bone mineral density in healthy postmenopausal women. The beneficial effect of dietary calcium on peak bone mineral density and in decreasing bone loss in cortical bone has been documented. Information regarding the prevention and treatment of bone loss in exogenous hypercortisolism and the magnitude and reversibility of bone loss associated with many diseases which affect bone has been obtained. One of the most important clinical applications of these techniques is the assessment of the efficacy of treatment of patients with postmenopausal osteoporosis. As antifracture efficacy is not readily measurable, considerable information is being obtained about many potentially useful forms of therapy that may prevent bone loss and increase bone mineral density. The role of these non-invasive methods in the assessment of fracture risk and the need for oestrogen or other therapy in an individual who has attained a low peak bone mass or has risk factors predisposing to excessive bone loss, differs from broader public health initiatives of population screening. There are concerns regarding the safety, efficacy and limited number of treatment regimens available for persons found by screening to be at risk. The most economic and convenient methods for predicting fracture risk with high sensitivity and specificity are not established. There are uncertainties regarding the relative importance of bone mineral density measured at the time of screening, the amount of bone lost in the subsequent years and risk factors predisposing to falls in the pathogenesis of hip fractures.(ABSTRACT TRUNCATED AT 400 WORDS)