Prevalence of hypercalciuria and urinary calcium excretion in school-aged children in the province of Tokat.

AIM Hypercalciuria is an important cause of urinary tract symptoms, and also frequently results in urolithiasis. Urinary calcium excretion varies for geographic areas. We aimed to assess percentiles of urinary calcium excretion and prevalence of hypercalciuria for school-aged children in Tokat (city located in inner northern region of Turkey). MATERIAL AND METHODS One thousand three hundred seventy-five children aged 6 to 18 years were enrolled in the study. Urine samples were obtained randomly. The children's variables as sex, age, length, and weight were recorded. Urinary calcium and creatinine determined from the urine samples and urinary calcium/creatinine ratios (mg/mg) were calculated. Percentiles of urinary calcium/creatinine ratios were also assessed for each age of the children. RESULTS Six hundred eighty-three of the 1 375 children were girls and 692 were boys. The mean age of the children was 11.68±3.43 years. Some 23.9% of the children were living in rural regions and 76.1% were were living in urban regions. The mean urinary calcium/creatinine ratio was 0.080±0.24 and the 95th percentile value of the urinary calcium/creatinine ratio was 0.278. The hypercalciuria prevalence for school-aged children was 4.7% when the urinary calcium/creatinine ratio value for hypercalciuria was accepted as ≥0.21. The prevalence of hypercalciuria in rural and urban regions was 7.60% and 3.82%, respectively (p<0.05). Hypercalciuria was present in 7 of 141 patients who were obese (4.96%) and 58 of 1 234 patients who were not obese (4.70%) (p>0.05). CONCLUSION The prevalence of hypercalciuria and urinary calcium excretion vary for different geographic areas, not only for countries. The percentiles of urinary calcium excretion should be assesed for every geographic region and the prevalance of hypercalciuria should be determined with these values. There is controversy as to whether obesity is a risk factor for hypercalciuria.