Long-term reduction in bone mass after severe burn injury in children.
Because burn victims are at risk of having bone loss, a cross-sectional study was undertaken to determine whether severe burn injury had acute and long-term effects on bone mass or on the incidence of fractures in children. Dual-energy x-ray absorptiometry of the lumbar portion of the spine was performed on 68 children: 16 moderately burned (15% to 36% of total body surface area) and 52 age-matched severely burned (> or = 40% of total body surface area). Twenty-two severely burned children were hospitalized and studied within 8 weeks of their burn, and 30 others were studied approximately 5 years after discharge. In the severely burned group, both hospitalized and discharged, serum and urine were analyzed for calcium, phosphorus, intact parathyroid hormone, osteocalcin, and type I collagen telopeptide. Sixty percent of severely burned patients had age-related z scores for bone density less than -1, and 27% of severely burned patients had age-related z scores for bone density less than -2 (p < 0.005, for each). In the moderately burned group, 31% of patients had z scores less than -1 (p < 0.005 vs normal distribution), but only 6% had z scores less than -2 (p value not significant). There was evidence of increased incidence of fractures after discharge in the severely burned patients. Biochemical studies were compatible with a reduction in bone formation and an increase in resorption initially, and with a long-term persistence of low formation. We conclude that acute burn injury leads to profound and long-term bone loss, which may adversely affect peak bone mass accumulation.