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

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).

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.

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.

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.