What is the real risk factor of urinary calculi in Iranian children?

The earliest reports on urolithiasis in Iranian children in 1980s revealed calcium oxalate and ammonium acid urate were the most common components of urinary calculi.1-3 Since then there have been increasing numbers of published studies about the risk factors of urolithiasis in Iranian children. A cross-sectional study conducted by Akhavan and coworkers4 showed the incidence of urinary calculi in school-aged children in Qom was 1% . They simultaneously studied the urinary excretion of metabolic factors in those schoolaged children. Surprisingly, 23% of asymptomatic children without calculus showed hypercalciuria and all of them had hypocitraturia.4 The result should be interpreted cautiously because of potential technical error, different normal ranges for Iranian children, or nutritional factors. Alamzadeh-Ansari and colleagues studied 152 infants with microlithiasis and urolithiasis by collecting 24-hour urine samples in south-west of Iran.5 In their report published in this issue of the Iranian Journal of Kidney Diseases, they detected that 92% had metabolic disorder, family history of urinary calculi was positive in 67%, and at least one-third of parents had consanguinity marriage. Similarly, the most metabolic disorders in this study were hypercalciuria and hypocitraturia. They mentioned neither the rate of mixed metabolic disorders nor the other risk factors such as dehydration, low fluid intake, and the diet of