Hypercalciuria in Jahrom's school-age children: what is normal calcium-creatinine ratio?

INTRODUCTION

The purpose of this study was to determine normal reference values for urine calcium-creatinine (Ca/C) ratio in Iranian children of Jahrom, in south-east of Iran.

MATERIALS AND METHODS

A total of 1068 school-age children were included by stratified clustered random sampling from primary schools of Jahrom, Iran, between March 2008 and May 2008. Nonfasting random urine specimens from each subject were analyzed for calcium and creatinine concentrations.

RESULTS

The mean ratio of urine Ca/C in all children was 0.123 +/- 0.106 (range, 0.01 to 2.25), and the 95th percentile value was 0.25. Nonfasting Ca/C ratios were not significantly different between the boys and the girls. The Ca/C ratio was highest in 9-year-old children (mean, 0.132 +/- 0.11). Based on the 95 percentile value of urine Ca/C (> 0.25) in the present study, 5.1% of the children in Jahrom were hypercalciuric. The prevalence of hypercalciuria differed with age (P = .06), and the most prevalent rate was observed in 9-year-old group (9.3%).

CONCLUSIONS

We provided a reference value for urine Ca/C ratio in south-east Iranian children. A child's age and ethnicity should be taken into consideration when assessing the urinary solute-creatinine ratios.