Osteoporosis and Mechanisms of Skeletal Aging

Abstract

Osteoporosis is a generalized skeletal disorder in which decreases in bone mass and bone quality lead to increased bone fragility and contribute to risk of fracture. It can affect people at any age, but its prevalence and clinical consequences increase exponentially with age. Fractures are particularly detrimental in the elderly population because they may lead to decreased quality of life, loss of independent living, a decline in health status, and death. Skeletal aging has been a subject of extensive research, with gradual uncovering of mechanisms mediating the loss of bone strength. Among these are bone matrix alterations, genetic and epigenetic mechanisms, age-related changes in bone metabolism and stem cells, declines in osteotrophic hormones, and changes in inflammatory and stress processes. Clinical and epidemiologic studies have also contributed to our understanding of fracture pathophysiology by identifying the risk factors for fractures and their interactions with aging. In addition, management of osteoporosis in the elderly has advanced through the development of an array of therapeutic agents with documented anti-fracture efficacy. Finally, it has become increasingly clear that the most effective approach to fracture prevention includes not just use of pharmacologic agents but addressing the whole patient through appropriate diet, activity, and overall health optimization. A growing understanding of the biological processes of aging and cross-talk between different tissues and organ system offers new approaches to prevent and treat osteoporosis. It is likely that the future of geriatric care will be transformed through a better integration of clinical observations and basic science discoveries.