Specific Aims: 1) To measure bone mineral content and bone mineral density and their change during growth in convalescent burned children admitted to a regional burn center and to compare them to normal, healthy children.; 2) To measure lean body mass, fat mass, total body water in convalescent burned children admitted to a regional burn center and compare them to normal, healthy children with focus on how these components of body composition relate to indices of bone mineral content and density; 3) To identify alterations in bone metabolism and calcium and vitamin D homeostasis following burn injury and relate these to bone mineral density in burned children; 4) To test the effect of short term calcium and vitamin D supplementation on improving bone mineral density, bone mineral content, and indices of calcium and vitamin D metabolism in acutely burned children.