Parenteral nutrition-associated metabolic bone disease.

The incidence of parenteral nutrition-associated metabolic bone disease is unknown. Initial reports from the early 1980s suggested that both osteoporosis and osteomalacia were quite common in patients who receive long-term parenteral nutrition. The findings described in these early surveys provide a snapshot into the many factors that contribute to the development of metabolic bone disease. More recent evidence suggests that bone loss may not be as great with the initiation of parenteral nutrition as once was thought, and that most of the metabolic bone disease that is noted may be related to the patient's underlying illness. Although this recent information is reassuring, it is of the utmost importance to provide parenteral nutrition that minimizes further bone loss and promotes the formation of new bone. This review will describe the general features of metabolic bone disease and the abnormalities noted with parenteral nutrition-associated metabolic bone disease, highlight the importance of preexisting illness and parenteral nutrition associated factors that contribute to the development of metabolic bone disease, and finally discuss an approach to avoid this debilitating complication of long-term parenteral nutrition.