We investigated the effects of demographic , lifestyle ( self-reported smoking status and physical activity levels ) , cancer-related treatment factors ( radiation and chemotherapy ) , and diet ( calcium and vitamin D intake ) on bone turnover and the relationship of bone turnover to lumbar spine bone mineral density ( BMD ) Z-scores ( LS-BMD Z-scores ) determined by quantitative computed tomography ( QCT ) in @ @-year survivors of childhood acute lymphoblastic leukemia ( ALL ) .