A study of the etiology of idiopathic calcium urolithiasis in children: Hypocitruria is the most important risk factor

Purpose: To determine the association of metabolic risk factors with pediat ric calcium urolithiasis we compared metabolic evaluation data on children with idiopathic calcium stones and those on healthy children. Materials and Methods: Metabolic evaluation was done in 78 calcium stone fo rmers 1 to 15 years old (mean age 7.2) who were free of urinary tract infec tion, anatomical abnormalities, and metabolic, endocrinological and intesti nal disorders, and in 24 healthy children. Evaluation included serum bioche mistry, and measurement of daily excretion of urinary calcium, oxalate, ura te, phosphorus, citrate and magnesium. Results: Demographic characteristics, serum parameters, and daily excretion of calcium, urate, phosphorus and magnesium did not differ statistically i n the 2 groups. However, urinary oxalate was significantly higher and urina ry citrate was significantly lower in stone formers than in controls (p = 0 .002 and 0.028, respectively). Hypocitruria and hyperoxaluria were 4.3 and 3-fold more common in stone formers than in controls, respectively. Multiva riate analysis using logistic regression showed that hypocitruria was the o nly significant risk factor for idiopathic calcium stones (p = 0.008). Conclusions: Hypocitruria was the most important risk factor in our patient s. Hyperoxaluria was also common and accompanied hypocitruria in many stone formers. In contrast to many previous reports, we failed to show that hype rcalciuria is an important metabolic defect for idiopathic calcium stones, possibly because our study evaluated a different population.