Pathogenesis and management of osteoporosis in thalassemia.

Osteopenia and osteoporosis cause severe problems in thalassemic patients. The pathogenesis of bone loss in thalassemia is multifactorial. The delay in sexual maturation, the presence of diabetes and hypothyroidism, the parathyroid gland dysfunction, the accelerated hemopoiesis with progressive marrow expansion, the direct iron toxicity on osteoblasts, the iron chelators, the deficiency of growth hormone or insulin growth factors, all have been identified as major causes of osteoporosis in thalassemia. However, despite the normalization of hemoglobin levels, adequate hormone replacement and effective iron chelation, patients continue to show an unbalanced bone turnover with an increased resorptive phase resulting in seriously diminished bone mineral density (BMD). During the last decade bisphosphonates have been used for the management of osteoporosis in thalassemia. Alendronate, pamidronate and zoledronic acid have shown efficacy in increasing BMD in thalassemic patients. However, further trials must be conducted in order to clarify the exact role of each bisphosphonate, the long-term benefit and side-effects as well as the effects of the combination of bisphosphonates with other effective agents, such as hormonal replacement, on thalassemia osteoporosis.