Osteoporosis-manifested by low bone mineral density, lessened skeletal integrity, and increased risk of fracture, is a major public health problem among the elderly. The skeleton has two major functions: it provides structural support and serves as a mineral reservoir. The skeleton is dependent on a homeostatic balance of the systemic and local bone modulators, mechanical loading, and nutrition. Changes in any one of these components, common in the elderly, can influence the systemic and local factors in bone turnover or change the sensitivity "set-point" of bone to challenges, whether biochemical or mechanical. This issue of Topics in Geriatric Rehabilitation (21:1) is devoted to an overview of the disease, current and future cost to the healthcare system, and morbidity and mortality. Advances in the dominant technology, dual-energy x-ray absorptiometry, for patient evaluation and management are reviewed.

The importance of integrated patient management using physical therapy, such methods as core strengthening using Pilates, muscle and skeletal strengthening exercise, and nutrition and drug interventions are emphasized. Although osteoporosis does not seem to be completely preventable, current preventive strategies and the role of mechanical loading (exercise) in the prevention and management of osteoporosis are addressed. While it is not feasible to review all aspects of the current research related to understanding the underlying contributors to the development of osteoporosis, the current areas of research are summarized. The basic control of bone at the cellular level clearly involves both nature and nurture. The developing skeleton has multiple genes that control the general characteristics of skeletal size and shape as well as macroarchitecture and microarchitecture responses to nutrition and environmental loading. One's lifestyle from childhood to maturity clearly influences skeletal integrity in the elderly. Skeletal loading is critical over the life span for skeletal health. In addition to genetic control, research has demonstrated the importance of nutrition and exercise in maintaining skeletal integrity.

Significant advances have been made in medical intervention's potential to reduce the loss of bone in older adults and to treat osteopenia (low bone mineral content) and osteoporosis. The methods of quantification of calcium and phosphorus in the skeleton have permitted early detection of low bone mineral and allow for early interventions, which have a significant impact in the prevention of facture in the future. However, there are still fewer than 65% of those with osteoporosis that have been diagnosed and close to 85% that are untreated. The economic cost to the healthcare system if these figures are not reduced is delineated in the article by Vanness and Tosteson. Currently the cost is 22 billion a year, with the projected cost climbing to 44 billion by the year 2025. As Bloomfield reports, osteoporosis is not necessarily a disease started in the mature adults but may be related to inadequate nutrition and/or exercise in childhood inhibiting the skeleton from reaching a person's full genetic potential. While future research is necessary to more fully delineate the underlying causes of osteoporosis, current research provides guidelines by which the incidence of osteoporosis and its morbidity may be significantly reduced.

Osteoporosis is a preventable disease, if diagnosed and treated early. While the scientific evidence is not complete, it is clear that those persons with a lifetime of exercise have significantly larger skeletons than those who have led sedentary lives. The scientific community has suggested 3 strategies for the prevention of osteoporosis in the older adult: (1) during childhood grow a larger skeleton with high-impact exercise; (2) maintain peak skeletal mass and strength after maturity until in the fifties; and (3) minimize bone loss after 50 in men, and in women after menopause. Diet and exercise are an integral part of all three strategies; however some individuals will not be able to prevent bone loss with diet and exercise alone. These persons will require a pharmaceutical intervention as well as exercise in order to maintain skeletal mass. As in all other organ systems of the body, the concept of "Use It or Lose It" is still key to maintaining skeletal integrity. The availability of dual-energy x-ray absorptiometry clearly provides a method for early diagnosis of osteoporosis in those persons with low bone mineral density who will require pharmaceutical intervention. However, society must decide that prevention of osteoporosis is important enough to implement the strategies that have been outlined in order to minimize the morbidity and mortality caused by osteoporosis in the older adult.