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.