Guidelines for the use of biochemical markers of bone turnover in osteoporosis (2004)

A definition of osteoporosis was agreed upon at the 1993 consensus conference held in Hong Kong. It states that osteoporosis is “characterized by low bone mass and the microarchitectural deterioration of bony tissue, with a consequent increase in bone fragility and susceptibility to fracture.” This definition had been internationally used without revision until recently, when the definition was significantly changed at a National Institutes of Health (NIH) consensus conference in 2000 [1]. According to the consensus statement, osteoporosis is defined as “a skeletal disorder characterized by compromised bone strength predisposing a person to an increased risk of fracture.” Bone strength is determined by integrating bone mineral density (BMD) and bone quality. BMD is expressed as grams of mineral per area or volume, and, currently, BMD is defined by the individual peak bone density and the resorption rate from the peak. Bone quality is determined by characteristics of the bone matrix, such as microarchitecture, bone turnover, microdamage accumulation, the degree of calcification, and collagen [2,3]. Currently, it is thought that bone quality may not be clinically assessed by measures other than the determination of bone metabolism with biochemical markers of bone turnover. The change in definition may be the result of more recent findings [4], one that demonstrates bone fractures routinely occur despite patients having modest BMD levels, and another that has shown no significant reduction in the risk of a fracture occurring in patients taking one of the two standard medications, one that significantly increases BMD and the other that moderately increases it.