Predictors of bone loss in childhood hematologic malignancies: a prospective study.

SUMMARY

Twenty-nine children with malignancies and age, gender-matched controls were prospectively studied over 14 months. Patients had higher parathyroid hormone (PTH) levels and fat mass, lower bone mass, and bone mass increments at follow-up than controls. Lean mass, age at diagnosis, systemic and intrathecal therapy were predictors of bone mass changes on adjusted analyses.

INTRODUCTION

Children with hematologic malignances have low bone mass. We prospectively investigated anthropometric, clinical, and hormonal predictors of changes in bone mass in children receiving cancer therapy.

METHODS

Twenty-nine children, mean age of 9 ± 2.9 years and 32 age and gender-matched controls, were studied. Seven had completed their course 40 ± 22 weeks prior, while 22 were still receiving therapy for 80 ± 28 weeks. Age at diagnosis, calcium intake, exercise activity, systemic corticosteroids in dexamethasone (Dex) dose, and methotrexate (MTX), and intrathecal MTX therapy received within follow-up period were assessed. Routine chemistries, PTH, 25-hydroxy vitamin D (25-OHD), bone remodeling markers, bone mass, and body composition were measured at baseline and 14 months.

RESULTS

Patients had lower exercise activity, sun exposure, and bone markers levels than controls. They had higher PTH levels and fat mass, lower bone mass at the spine, hip, and total body, and lower increments at these sites on follow-up. Predictors of bone mass changes on univariate analyses were: age at diagnosis (R = -0.50 to -0.44, p < 0.05), Dex-MTX doses (R = -0.58 to -0.41, p < 0.05), intrathecal therapy (p < 0.03),% changes in lean mass (R = 0.37 to 0.54, p < 0.04), 25-OHD levels (R = 0.39, p < 0.03), and PTH levels (R = -0.47 to -0.41, p < 0.05). Lean mass, age at diagnosis, systemic and intrathecal therapy were predictors of bone mass changes on adjusted analyses.

CONCLUSION

This study provides insight into the pathophysiology of bone loss in children receiving cancer therapy and possible interventions to optimize their skeletal health.