Osteoporosis

Abstract

Osteoporosis is a skeletal disorder characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to an increase in bone fragility and susceptibility to fracture. An operational definition of osteoporosis has also been defined, based on a value for bone mineral density (BMD) 2.5 standard deviations or more below the young adult mean [1]. The most widely validated technique for the quantitative assessment of BMD is dual-energy X-ray absorptiometry. Bone loss is due to an imbalance between bone resorption by osteoclasts and bone formation by osteoblasts, which are part of the bone remodeling process. This results in a decrease in BMD and alterations of bone geometry and micro-architecture at the cortical and trabecular sites, leading to bone fragility and fractures. Osteoporosis has the potential to alter quality of life and to increase mortality. From the age of 50 years, 50 % of women and 20 % of men will be concerned by fracture during their remaining lifetime. This important public health issue will tend to increase due to the aging of the world population. Beyond aging, many pathological conditions (e.g., endocrine diseases, chronic inflammatory diseases) or treatments (e.g., corticosteroids) interfere with bone metabolism and induce osteoporosis.