Low bone mass in prepubertal children with thalassemia major: insights into the pathogenesis of low bone mass in thalassemia.
OBJECTIVE: Low bone mass occurs frequently in the aging thalassemic population. However, limited information exists on bone mass in children with thalassemia major (TM) during their first decade of life. STUDY DESIGN: Spinal bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DEXA) in 18 children (age 5.8 +/- 1.5 yr; M:F 8:10) with TM on hypertransfusion and iron chelation therapy. Serial BMD measurements were available for 11 of the 18 children. RESULTS: Weight and height z scores were 0.81 +/- 4.2 and -0.47 +/- 1.7 respectively. At the first BMD, four (22.2%) patients presented with BMD z scores less than -2.5, seven (38.8%) had BMD z scores between -1 and -2.5, while the remaining seven (38.8%) had normal BMDs (z score above -1). The mean decline of BMD z score was -0.38/year (p = ns). BMD z scores correlated with height z scores (p = 0.039), but not with liver enzymes, serum ferritin levels, or thalassemia genotypes. CONCLUSIONS: Low bone mass is present in most children with TM despite hypertransfusion and optimal chelation, adequate growth and lack of endocrine complications.