Bone mineral density is reduced in brain tumour patients treated in childhood

AIM: To determine the prevalence of low bone mineral density among children surviving brain tumours and to identify possible factors underlying impaired bone health. METHODS: Cross-sectional study; total body bone mineral density (TBBMD), fat mass (FM) and lean body mass (LBM) were measured by dual-energy X-ray absorptiometry (DXA) in 46 brain tumour patients aged from 3.8 to 28.7 y (mean 14.9 y) treated in childhood 1.4-14.8 y (mean 6.4 y) after end of treatment for brain tumour. Low bone mineral density was defined as TBBMD z score < - 2.0. RESULTS: Fifteen patients had TBBMD z scores < - 2.0, indicating a 33% prevalence of low bone density. The TBBMD z score ranged from -5.7 to 0.6 (mean -1.7). Out of several potential factors, only combined craniospinal irradiation was significantly associated with low z score (p=0.034, according to multiple regression analysis), while exclusive cranial irradiation showed a borderline statistical association (p=0.100, according to multiple regression analysis). CONCLUSION: One third of brain tumour patients treated in childhood had reduced bone mineral density. The reasons for this condition are apparently multifactorial, including craniospinal irradiation.