Bone mineral density in childhood acute lymphoblastic leukaemia survivors and factors affecting it.

Background: Literature on bone health in childhood acute lymphoblastic leukemia survivors (cALLS) is conflicting with most studies suggesting an adverse effect on bone mineral density (BMD). Methods: This cross-sectional study enrolled cALLS>7 years of age. BMD was measured using dual-energy x-ray absorptiometry (DEXA) scan [Lumbo-sacral (LS-BMD) and whole-body (WB-BMD)]. Low BMD was defined as an LS-BMD ≤2 z-score. Demographic, anthropometry-related, therapy/disease-related and endocrine factors affecting LS-BMD were noted in two groups: low verses normal BMD. Results: Fifty-nine cALLS were analyzed with a median age of 66 months (range: 6-212) at diagnosis and a median duration postcompletion of therapy for 14 months (range 1-113). Two-thirds were male, and 25/59 (42%) had Tanner staging>1. Low LS-BMD was seen in 15/59 (25%), and a low WB-BMD in 3/59 (5%). The mean therapeutic doses of steroids and methotrexate were comparable in two groups. In univariate analysis, age at diagnosis >10 years was associated with low BMD (p = 0.02), while high adiposity was seen commonly with normal BMD (p = 0.01). On multivariate analysis, high adiposity was the single-most factor associated with normal BMD, with an odds ratio of 5.2. The correlation between LS-BMD and WB-BMD was statistically significant (r = 0.55).The median values of hormonal and mineral assays affecting calcium and vitamin D homeostasis and BMD in the two groups were comparable. Conclusion: We report a high prevalence of low LS-BMD (25%) in our cohort. Out of the studied demographics, therapy-related, disease-related, and endocrine factors; high adiposity as defined by a high body fat percentage, was protective against low BMD. We also found a significant correlation between LS-BMD and WB-BMD.