URINARY CALCIUM-OXALATE SATURATION IN HEALTHY INFANTS AND CHILDREN

Purpose: A number of factors influence the development of renal calcul i, the most essential of which is the supersaturation of urine with li thogenic substances. Calcium oxalate stones occur most frequently in a dult and pediatric patients with urolithiasis. Therefore, we establish ed normal age and sex related data for urinary calcium oxalate saturat ion in infancy and childhood to allow a more specific prediction of th e risk of (recurrent) stone disease. Materials and Methods: We collect ed 24-hour urine samples from 473 healthy infants and children without a history of renal stones. Urinary lithogenic and stone inhibitory su bstances were measured, and the urinary calcium oxalate saturation was calculated using a computer program. Results: Mean urinary calcium ox alate saturation was always higher in boys than in girls, which was si gnificant in infancy (5.22 versus 2.03, p < 0.05) and at ages 7 to 9 y ears (8.84 versus 5.47, p < 0.05). The saturation first increased (p < 0.05) until age 7 to 9 years in boys and girls, and remained at high levels at ages 10 to 12 years (7.03 versus 5.49, p < 0.05 compared to infancy). Calcium oxalate saturation then decreased until adolescence when values were comparable to those of infancy (5.29 versus 3.35). Co nclusions: We recommend calculating urinary calcium oxalate saturation for diagnostic purposes as well as for therapy control. Normal age an d sex related values must be considered.