Total body bone measurements: a cross-sectional study in children with acute lymphoblastic leukemia during and following completion of therapy.

BACKGROUND: Abnormalities in bone mineral density (BMD) occur in children treated for acute lymphoblastic leukemia (ALL). However, BMD estimates have been performed using varied instruments, reference data, and interpretations. This exploratory cross sectional study to evaluate bone mass in children with ALL, uses an algorithm that serially adjusts for variables known to affect pediatric bone measures by dual energy X-ray absorptiometry (DXA), based on models developed in 1,218 healthy children and adolescents. PROCEDURE: Anthropometry, DXA scans, and factors with possible influence on bone mass were evaluated in 21 ALL patients receiving chemotherapy and 20 in the follow-up phase. Main outcome was treatment group differences in Z-scores for total body bone mineral content (BMC), bone area (Area), and areal BMD (aBMD).
RESULTS: Mean Z-scores for the entire study population for BMC, Area, and aBMD were significantly less than zero. Among possible contributing factors, only calcium intake was a significant co-variate. Comparison between treatment groups showed that least-square mean Z-scores for patients on-therapy for at least 12 months were significantly lower than those off therapy for at least 12 months (P: 0.0008-0.044), except for BMC at last step of the algorithm (adjusted for sex, age, ethnicity, height, weight, and bone area).
CONCLUSIONS: Evaluation of total body DXA by this algorithm is consistent with better general bone status in those off-therapy. However, in this small exploratory study, the lack of significant difference between Z-scores for fully adjusted BMC in on- versus off-therapy groups suggests possible risk of low peak bone mass. Additional longitudinal evaluation is warranted.