Epidemiology, etiology, and diagnosis of osteoporosis.

Osteoporosis is a major cause of morbidity among the elderly; more than 40% of women will suffer from fractures by the time they reach the age of 70. Recent research has focused on the determinants of postmenopausal osteopenia and of postmenopausal osteoporosis. The bone density of elderly people may depend on peak bone mass in adolescence, and recent studies have tried to define the respective roles of genetic factors, nutrition, and exercise in the attainment of peak bone mass. Maintenance of bone mass throughout adult life may be influenced by different factors: the potential role of thiazides in preserving bone density in elderly patients has been suggested; the deleterious effects of steroid therapy on the skeleton has been confirmed, and new information on the course and pathogenesis of steroid-induced osteopenia has been uncovered. Some reports have expressed concern over the possible adverse effects of L-thyroxine therapy on skeletal integrity, whereas others present reassuring data. The importance of bone mass measurements in predicting who is at risk for osteoporosis has been confirmed, and preliminary screening guidelines have been proposed.