Idiopathic Hypercalciuria in Iranian Children

Objective: The aim of this study was to determine the prevalence of idiopathic hypercalciuria (IH) in school children in Ahvaz, a city with different ethnic groups located in the Southwest of Iran.
Material & Methods: In a descriptive cross sectional study from October to December 2006, we determined urinary calcium (UCa) and urinary creatinine (UCr) in the morning urine samples of 500 primary school children. The levels of 24-hour UCa and UCr were measured in these children. Level of 24-hour UCa exceeding 4 mg/kg/day was considered as hypercalciuria, and UCa/UCr ratio exceeding 0.21 (mg/kg) was considered abnormal. Children who had hypercalciuria with a normal concentration of serum Ca were categorized as idiopathic hypercalciuric.
Findings: Of 500 children aged 6-12 years, 231 were males and 269 females. In the first screening, 64 (12.8%) children (45 males, 19 females) had an abnormal UCa/UCr ratio. But in the end only 15 had the criteria of IH, i.e. the prevalence of IH was 3% (1.8-4.8%, confidence interval of 95%). The prevalence in females and males was 0.74% and 5.6%, respectively (P= 0.003). Of these children 10 had hematuria (including 2 cases of gross hematuria), 8 children gave a history of recurrent abdominal pain, 5 children suffered from dysuria and 3 persons had a history of personal or familial urolithiasis.
Conclusion: The study showed that 3% of primary school children in Ahvaz had IH predisposing to short-term and long-term complications of the disease. IH was significantly more common in boys than in girls.