Emerging views about "osteoporosis", bone health, strength, fragility, and their determinants.

Recent articles by Drs. Lanyon, Raisz, Seeman, and Skerry summarized some emerging views about the causes and nature of some effects of mechanical loading on bones and "osteoporosis", the causes of fractures in that condition, and the causes of increased bone fragility and age-related bone loss. This article would supplement theirs with further evidence and ideas. This includes a definition of bone health that suggests currently popular classifications of "osteoporosis" and "osteopenia" could fail to distinguish healthy differences from normal averages from true bone diseases. This definition also suggests a classification of osteoporotic fractures that could question some current methods and uses of noninvasive absorptiometry. This article emphasizes concepts and generalities, and leaves resolution of any devils in the details to other places, times, and people.