The WHO Definitions of Osteoporosis Tell the Truth, But Not the Whole Truth

"nThese WHO definitions describe various degrees of decreased bone density and consider all cases to be related to osteoporosis, but do not take into consideration other causes of diminished bone density. "nThe WHO approach exemplifies a Persian proverb that “walnut is round, but everything round is not a walnut”. It is true that “Osteoporosis has diminished bone density, but every case of diminished bone density is not related to osteoporosis”. "nThe main objective of this presentation is to complement the 1994 WHO “definitions” of quantitative measurement of diminished bone density by “DEXA” with a “radiopathophysiological classification” to consider, in addition to osteoporosis, other causes of diminished bone density, while discussing the basic principals and various forms of metabolic bone disease very briefly. "nWHO definitions "nOsteopenia: Generalized diminished bone mineral density (DBMD) of any cause or of unknown etiology. Osteopenia includes: osteoporosis, osteomalacia, and osteolysis. "nOsteoporosis: Inadequate osteoid production by osteoblasts. Consequently, there is decreased bone formation. "nOsteomalacia: Inadequate osteoid mineralization."n Osteolysis: Generalized increased rate of bone destruction by osteoclasts and/or caused by marrow packing disorders. "nAn attempt is made to correlate the 1994 World Health Organization (WHO) definitions of osteoporosis with a radiopathophysiological classification of “Generalized Diminished Bone Mineral Density” (GDBMD). The main purpose is to make the two systems complementary. "nThe WHO “definitions”, are basically concerned with various stages of osteoporosis. Most, but not all cases of “Generalized Diminished Bone Mineral Density” (GDBMD) are due to osteoporosis. "nOur approach will give a road map to distinguish osteoporotic cases from non-osteoporotic entities, such as various forms of osteomalacia, hyperparathyroidism, multiple myeloma, Gaucher disease, and other forms of GDBMD.