[Osteoporosis - inflammatory effects on bone metabolism and fracture risk]

There is a large body of evidence that proinflammatory cytokines, particularly interleukin-1, interleukin-6, and tumour necrosis factor-α, play an important role in bone metabolism. Moreover, it is suspected that proinflammatory cytokines are also important in the pathogenesis of age- and estrogen deficiency-related bone loss. Although an accelerated decrease in bone mass is observed in patients with chronic inflammatory disorders, the definite meaning of proinflammatory cytokines in the aetiology of osteoporosis is still unclear. Some studies suggest a relationship between increased concentrations of proinflammatory cytokines and a decrease in bone mineral density, as well as an increased risk of fracture. In sum, the evidence is rather scarce and does not permit any clear conclusions about the effects of single cytokines in bone metabolism. To be able to define more exactly at which stage of the pathogenesis of osteoporosis parameters of a systemic inflammation take effect, further studies will be necessary, particularly for developing suitable diagnostic markers for clinicians. These diagnostic markers may be able to identify patients at risk for osteoporosis and therefore predict fracture risks. Thus, early interventions to preserve bone health, for example, by anti-cytokine therapy, could be more effective and efficient.