Longitudinal changes in body mass and composition in survivors of childhood hematologic malignancies after allogeneic hematopoietic stem-cell transplantation

Purpose: To measure longitudinal changes in body mass and composition in survivors of childhood hematologic malignancies after allogeneic hematopoietic stem-cell transplantation (HSCT). Patients and Methods: Body mass index (BMI) was analyzed in 179 survivors by category (underweight, healthy-weight, overweight, and obese) and by z score. Fat and lean body mass measured by dual-energy x-ray absorptiometry was analyzed as z scores. Results: Over a median 6.6 years of follow-up, BMI z scores diminished significantly (0.32 pre-HSCT v -0.60 at 10 years post-HSCT; P < .001). Mean z scores for fat mass stayed within population norms, but those for lean mass remained below normal levels and diminished significantly over time (P = .018). Pre-HSCT BMI category and/or z score were strongly predictive of post-HSCT BMI (P < .001) and of fat and lean mass z scores (both P < .001). Survivors with extensive chronic graft-versus-host disease were more likely than others to have low BMI (P = .004) and low lean mass (P < .001) post-HSCT. Older age at HSCT (P = .015) and T-cell-depleted graft (P = .018) were predictive of lower post-HSCT BMI. Female patients had higher body fat (P = .002) and lower lean mass (P = .013) z scores than male patients, and black patients had higher fat mass z scores than white patients (P = .026). Conclusion: BMI declines significantly after allogeneic HSCT for childhood hematologic malignancies, reflecting primarily a substantial decrease in lean mass but not fat mass. Monitoring and preservation of BMI and lean mass are vital, especially in those with the identified risk factors.