Although osteoporosis has been de? ned as “a metabolic bone disease characterized by low bone mass and microarchitectural deterioration of bone tissue leading to enhanced bone fragility and a consequent increase in fracture risk,” it is not clear that osteoporosis represents a single disease as much as a similar response of bone to different pathophysiologies. In the 1940s Fuller Albright and colleagues recognized “osteoporosis of old age” and distinguished it from osteoporosis associated with the postme- pausal state, as well as from osteoporosis from disuse, osteoporosis from malnutrition, and other forms of osteoporosis. He nevertheless pointed out that it was unclear how much of osteoporosis is due to old age per se, in view of the fact that “in many cases osteoporosis of disuse, of malnutrition, of the postmenopausal state and of senility are inseparably superimposed. ” In this volume, Duque and Kiel have gathered an international panel of experts to highlight the unique features of senile osteoporosis and cons- eration of this disease spans the very basic through the clinical and the epidemiologic. As an organ which harbors stem cells, bone may clearly in? uence not only its own regeneration but also the regeneration of other tissues, notably the hematopoietic system.
