BACKGROUND: Osteopenia has been reported in children surviving acute lymphoblastic leukemia and brain tumors, apparently as a consequence of therapy. It has been suggested that cranial irradiation may play a role in the development of this complication. In order to explore that possibility, we examined survivors of brain tumors treated with and without radiation in childhood to investigate associations between radiation, osteopenia, physical activity, health status and overall health-related quality of life (HRQL). PROCEDURE: Subjects were survivors of posterior fossa tumors (astrocytoma or medulloblastoma) or optic glioma, < 18 years of age at diagnosis and > 1 year off treatment. Measurements of growth velocity, body composition, bone densitometry, physical activity and HRQL were undertaken. RESULTS: Twenty-five (62.5%) of the 40 eligible patients participated in the study. Of the 25 patients, 12 (48%) received radiation therapy (R group) while 13 received no radiation (NR group). Growth hormone (GH) deficiency had been detected in three subjects, one had completed GH therapy while two were still on hormone replacement. The prevalence of osteopenia was 44% in the entire group, and 67% versus 27% in the R and NR groups. Florid osteoporosis was present in 20% of the entire group, more than 40% of the R group but none of the NR group. A significant correlation (P < 0.01) was observed between overall HRQL and Z scores of bone mineral density (BMD) of the lumbar spine. Pain and ambulation/mobility utility scores correlated significantly (P < 0.05) with BMD, while levels of physical activity correlated (P < 0.05) with overall HRQL utility scores. CONCLUSIONS: This pilot study demonstrates that in survivors of brain tumors treated in childhood, radiation therapy is associated with significant loss of bone mineral. Among these survivors, HRQL is less, pain is more severe and ambulation is more restricted in those with low BMD scores. The reduction in HRQL is reflected in diminished physical activity. A larger multi-center study is needed to confirm these results.