ABSTRACT

The internationally agreed description of osteoporosis is a progressive systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture1. The description captures the notion that low bone mineral density forms a central component, but that other skeletal factors and also non-skeletal factors such as liability to falls are also important in the pathogenesis of fracture. Notwithstanding, the operational definition of osteoporosis is on the basis of bone mineral density (BMD) values, since these can be measured with some accuracy and precision, whereas this is not the case for other determinants of osteoporotic fracture risk. In 1994, the World Health Organization2 provided an operation definition in terms of bone mineral density. Osteoporosis was defined as a decrease in BMD in postmenopausal women that was equal to or greater than 2.5 standard deviations (SD) below the average value for young healthy women (a Tscore of ≤ –2.5 SD). With the development of more technologies and more epidemiological information in men, the reference standard has been set using dual-energy X-ray absorptiometry (DXA) at the proximal femur. The same criteria for osteoporosis are also applied to men3.