The main objectives of the study are:
* To estimate, using quantitative computed tomography (QCT), the prevalence of diminished bone mineral density (BMD) in patients treated with contemporary, protocol-based multiagent chemotherapy (+cranial irradiation) for childhood acute lymphoblastic leukemia (ALL).
* To investigate possible risk factors for the development of diminished BMD in patients treated with contemporary protocol-based therapy for childhood ALL. Factors to be examined include patient characteristics (age at the time of treatment, gender, race, body mass index, physical activity and nutritional status, menarchal status, oral contraceptive use, growth hormone therapy, smoking and alcohol intake, birth weight, fracture history); treatment effects (intensity of treatment with antimetabolites and glucocorticoids; history of cranial irradiation); and genetic predisposition (i.e., vitamin D and CYP3A4 receptor polymorphism and family history of osteoporosis).
* To evaluate, in a prospective placebo-controlled double-blinded randomized trial, the effects of vitamin D and calcium supplementation in addition to nutritional counseling on BMD in patients with BMD scores below the mean for age- and gender-matched controls, compared to an educational program of nutritional counseling alone.
Secondary Aim
* To evaluate, in a prospective randomized trial, the correlation between BMD as determined by QCT and BMD as determined by dual energy x-ray absorptiometry (DEXA) in patients with BMD more than one standard deviation (SD) below the mean for age- and gender-matched controls.
