Potential role of serum vitamin D as a risk factor in pediatric acute lymphoblastic leukemia.

Vitamin D deficiency/insufficiency (VDD, VDI) is common in children yet limited experience exists on the association of VDD and hematologic malignancies amongst this population. Therefore, this study aimed to compare serum vitamin D levels in children with acute lymphoblastic leukemia (ALL) and controls. Moreover, vitamin D levels is compared in subjects with and without relapse and evaluated as a prognostic factor for relapse-free survival (RFS). Children with newly diagnosed ALL were recruited as case group. Data on demographic variables as well as the dietary habits were collected by interview. In addition, serum 25(OH)D3 was measured. The case group was followed up for 36 months to assess RFS. Overall, 358 subjects were included in the study (n = 169 cases, n = 189 controls). The mean levels of 25(OH)D3 were 28.05 ± 18.87 and 28.76 ± 12.99 in cases and controls, respectively (p = .68). VDD was found in 15.4% (n = 26) and 4.2% (n = 8) of the case and control groups, respectively (p < .001). Relapse was seen in 18.34% of patients and vitamin D levels of 20 ng/mL or above were associated with longer RFS (p = .044 by log-rank test). In this study, VDD and VDI amongst children with ALL were significantly higher than controls. In addition, lower levels of Vitamin D were associated with increased risk of relapse.