The bone-remodeling transient: implications for the interpretation of clinical studies of bone mass change

A computer simulation of the bone-remodeling transient is described, in which the focus is explicitly on changes in clinically measurable bone mass (or density). Based upon quantitative remodeling data accumulated by histomorphometry and calcium tracer kinetics, the simulation shows that much of the apparent gain in bone produced by several agents currently employed to treat osteoporosis can be explained as a remodeling transient rather than as a fundamental alteration of remodeling balance. Even gains as large as 30% or more can be produced by nothing more than the remodeling transient under certain plausible combinations of basal remodeling rate, remodeling period, and degree of bone loss. The simulation further highlights the importance, in evaluating bone-active agents, of separating the response across the first remodeling period from bone changes that may ensue thereafter.