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Urinary reference values for stone risk factors in children
Kristy M Borawski1, Roger L Sur, Oren F Miller
1Division of Urology, Duke University Medical Center, Durham, North Carolina, USA.
Insights
Urinary stone risk factors in children decrease with age. These findings provide reference values for 24-hour urine samples in healthy children, aiding in the diagnosis of pediatric kidney stones.
Area of Science:
- Pediatric Nephrology
- Urology
- Clinical Chemistry
Background:
- Limited reference values exist for 24-hour urine stone risk factors in non-stone forming children.
- Understanding age-related changes in these factors is crucial for accurate diagnosis.
Purpose of the Study:
- To measure urinary stone risk factors in healthy children aged 3 to 18 years.
- To determine if age influences these risk factors in 24-hour urine samples.
Main Methods:
- 48 healthy children without a history of stone disease were recruited.
- 24-hour urine samples were analyzed, with chemistries adjusted for urinary creatinine and body weight.
- Subjects were stratified into four 5-year age groups.
Main Results:
- Urinary pH and volume decreased with increasing age.
- Adjusted urinary parameters (calcium, oxalate, uric acid, citrate, magnesium, sodium, phosphorus, potassium) showed a statistically significant decrease with age, except for calcium.
- Unadjusted parameters did not show significant age-related differences.
Conclusions:
- Urinary stone risk factors decline with age in healthy children.
- Normative data, adjusted for creatinine or body weight and stratified by age, can help identify abnormal stone risk factors in pediatric patients.
- This study provides valuable reference ranges for pediatric urolithiasis evaluation.
Purpose:
Reference values for stone risk factors in 24-hour urine samples for nonstone forming children are limited. We measured urinary stone risk factors in healthy children 3 to 18 years old, and sought to determine whether the risk factors are affected by age.
Materials And Methods:
A total of 48 healthy subjects with no history of stone disease, endocrine abnormalities or urological surgery were recruited from the Naval Medical Center in San Diego. Subjects were then further divided into 4 age groups, each separated by 5 years. A single outpatient 24-hour urine sample was obtained and analyzed. Urine chemistries were adjusted for urinary creatinine and body weight.
Results:
After excluding under collected samples 46 urine samples were analyzed. Urinary pH and volume decreased with increasing age, although the difference in pH did not reach statistical significance. Unadjusted urinary parameters failed to show statistical difference among the age groups. When adjusted for urinary creatinine and body weight all urinary parameters (calcium, oxalate, uric acid, citrate, magnesium, sodium, phosphorus and potassium) decreased with increasing age (statistically significant except for calcium).
Conclusions:
Stone risk factors in 24-hour urine samples decrease with increasing age in healthy, nonstone forming children. Normative data, derived by adjustment with urinary creatinine or body weight and stratified according to quintiles of age, should be useful in defining abnormal stone risk factors in children with stones.
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