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[Analysis of the urinary risk factors of urolithiasis in healthy children]
Insights
Children exhibit higher urine inhibitory activity against calcium oxalate stones due to increased magnesium and lower calcium levels. These factors contribute to reduced urolithiasis risk in pediatric populations.
Area of Science:
- Urology
- Pediatric Nephrology
- Biochemistry
Background:
- Idiopathic calcium oxalate urolithiasis is rare in children.
- Understanding risk factors for pediatric urolithiasis is crucial for prevention.
Purpose of the Study:
- To analyze risk factors for calcium oxalate stone formation in male volunteers across different age groups.
- To investigate the role of urine inhibitory activity and specific urinary components in preventing urolithiasis.
Main Methods:
- Urine samples were collected from four male age groups: 8, 11, 18-24, and 41-45 years old.
- Urine inhibitory activity was assessed using non-filtered and filtered samples (molecular weight cutoff 25,000).
- Urinary levels of uric acid, citrate, magnesium, uronic acid, and calcium were analyzed.
Main Results:
- Urine inhibitory activity was significantly higher in children (groups I and II) compared to adults (groups III and IV).
- Filtered urine showed reduced inhibitory activity, suggesting larger molecules (>25,000 MW) contribute, while smaller molecules (<25,000 MW) also play a role in children.
- Children had higher magnesium excretion and a higher magnesium/creatinine ratio, correlating with increased inhibitory activity.
- Children exhibited lower urinary calcium concentrations compared to adults.
Conclusions:
- Higher urine inhibitory activity in children is linked to increased magnesium and potentially lower calcium levels.
- Magnesium appears to enhance inhibitory activity, contributing to lower urolithiasis incidence in children.
- Substances with molecular weights both above and below 25,000 MW contribute to urine's stone inhibitory properties, with distinct roles in pediatric populations.
Abstract:
Since incidence of idiopathic calcium oxalate urolithiasis in children was very low, a study was made to analyze the risk factors of calcium oxalate stone in male volunteers without any episode of urolithiasis. They were divided into four groups, group I: eight years old, group II: 11 years old, group III: 18 to 24 years old, group IV: 41 to 45 years old. Inhibitory activities of urine were significantly higher in groups of children than in groups of adults. However, inhibitory activities of filtered urine, extracted through filters with conserved limit of 25000 of molecular weight, were reduced significantly. Therefore, it was suggested that materials with molecular weight over 25000 participated in the inhibitory activities. Furthermore, the activities of filtered urine of group I were still higher than those of the non-filtered urine in groups of adults. Accordingly it was considered that substances less than 25000 of molecular weight also participated in the inhibitory activities in children. An analysis of uric acid, citrate, magnesium and uronic acid in urine revealed that magnesium excretion volume and magnesium concentration ratio to creatinine were higher in children than in adults. Magnesium seemed to boost the inhibitory activities in children. In the measurement of crystalloid materials, the concentration of calcium was significantly lower in children groups than in groups of adults. It seemed that calcium also takes part in reduction of incidence of urinary stone in children.