Evaluation of bone mineral density in long-term survivors of childhood acute lymphoblastic leukemia

Background: The purpose of this study was to evaluate long-term changes in bone density profile among survivors of childhood acute lymphoblastic leukemia. Patients and Methods: This was a 5 year prospective study comprised of thirty-one survivors of childhood acute lymphoblastic leukemia with a mean age of 11.8 (4.6) years, who completed therapy at least 1 year previously (according to the ALL-6 therapeutic protocol), and remained in complete continuous remission. BMD was measured from the lumbar spines (L2 to L4) and femoral neck, at baseline (2006) and after 5 years (2011), using dual energy x-ray absorbtiometry. Bone mineral density Z score and bone mineral content were calculated for both lumbar spine and femoral neck. Results: The mean femoral bone mineral density was 0.69 in 2006 and 0.82 in 2011 (p=0.005). The mean femoral Z score was -1.38 in 2006 and -0.55 in 2011 (p=0.006). For the lumbar spine, the mean bone mineral density was 0.71 in 2006 and 0.88 in 2011 (p=0.000); and the mean Z score was -2.08 in 2006 and -0.93 in 2011 (p=0.000) respectively. All three indices significantly changed through-out the study period. The general linear regression analysis revealed that daily calcium intake was an important predictor of lumbar spine BMD Z score. Femoral neck BMD Z score was correlated with the serum vitamin D level. Conclusion: Osteopenia in survivors of childhood acute lymphoblastic leukemia constitutes an important health risk. Patients and their families should be encouraged to take sufficient amount of calcium and vitamin D during chemotherapy and afterward.