Urinary N-acetyl-beta-D-glucosaminidase activity in healthy children

Magnesium supplementation therapy to prevent cisplatin-induced acute nephrotoxicity in pediatric cancer: a randomized phase-2 trial

BACKGROUND

The present study aimed to examine the effect of magnesium (Mg) supplementation on cisplatin-induced nephrotoxicity (CIN) in pediatric cancer patients.

METHODS

The present phase-2, open-label, multicenter, randomized controlled trial enrolled patients aged less than 20 years who were scheduled to receive cisplatin-containing chemotherapy and randomly allocated them at a ratio of 1:1 to a Mg supplementation arm with even-numbered chemotherapy courses (arm AB) or another arm with odd-numbered courses (arm BA). Analysis objects were reconstructed into two groups depending on whether the chemotherapy course had Mg supplementation (group B) or not (group A). The primary outcome was the proportion of chemotherapy courses resulting in elevated serum creatinine per chemotherapy course. The secondary outcomes included efficacies evaluated using other biomarkers and the safety of the Mg supplementation.

RESULTS

Twenty-eight patients were randomly allocated to either group (16 to arm AB and 12 to arm BA). The baseline characteristics of the groups were similar. There was no significant difference in the proportion of courses with increased serum creatinine between the groups (group A: 10% vs. group B: 6%; P = 0.465) nor was any significant difference observed in other biomarkers during any chemotherapy course. The Mg value during chemotherapy was significantly higher in group B than that in group A. No adverse events related to magnesium administration were observed.

CONCLUSIONS

The study design, which treated a single chemotherapy course as a study object, failed to detect a statistically significant benefit of Mg supplementation for preventing CIN in pediatric cancer patients.

TRIAL REGISTRATION

JRCT ( https://jrct.niph.go.jp/ ) Identifier UMIN000029215 jRCTs031180251. UMIN-CTR ( http://www.umin.ac.jp/icdr/index.html ) Identifier UMIN000029215.

Role of urinary N-acetyl-beta-D-glucosaminidase in predicting the prognosis of antenatal hydronephrosis

PURPOSE

Urinary biomarkers are known to be able to diagnose renal damage caused by obstruction at an early stage. We evaluated the usefulness of urine N-acetyl-beta-D-glucosaminidase (NAG) to determine the prognosis of antenatal hydronephrosis.

MATERIALS AND METHODS

From January 2019 to December 2021, a retrospective study was performed on patients with grade 3 or 4 hydronephrosis. We analyzed the ultrasonographic findings and the urinary NAG/Cr ratio between the laparoscopic pyeloplasty (LP) group and active surveillance (AS) group.

RESULTS

A total of 21 children underwent LP for ureteropelvic junction (UPJ) obstruction and 14 children underwent AS. The mean age at the time of examination was 3.7 months (1.7-7.5 months) in the LP and 5.2 months (0.5-21.5 months) in the AS (p=0.564). The mean anteroposterior pelvic diameter was 30.0 mm (15.0-49.0 mm) in the LP and 16.7 mm (9.0-31.3 mm) in the AS (p=0.003). The mean renal parenchymal thickness was 2.6 mm (1.2-3.7 mm) in the LP and 3.8 mm (2.9-5.5 mm) in the AS (p=0.017). The urinary NAG/Cr ratio was 26.1 IU/g (9.8-47.4 IU/g) in the LP and 11.1 IU/g (2.6-18.1 IU/g) in the AS (p=0.003). After LP, the urinary NAG/Cr ratio was significantly reduced to 10.4 IU/g (3.4-14.2 IU/g) (p=0.023).

CONCLUSIONS

The urinary NAG/Cr ratio, one of the biomarkers of acute renal injury, is closely related to the degree of hydronephrosis. Therefore, it may be useful to determine whether to perform surgery on the UPJ obstruction and to predict the prognosis.

Exposure to an Extended-Interval, High-Dose Gentamicin Regimen in the Neonatal Period Is Not Associated With Long-Term Nephrotoxicity

Objectives: To assess the association between gentamicin exposure and subclinical signs of nephrotoxicity in school children who were exposed to a high-dose gentamicin regimen in the neonatal period. Methods: Children receiving three or more doses (6 mg/kg) of gentamicin as neonates were invited to a follow-up in school age. We evaluated potential signs of subclinical nephrotoxicity with four validated urine biomarkers: protein-creatinine ratio (PCR), albumin-creatinine ratio (ACR), kidney injury molecule-1 (KIM-1), and N-acetyl-beta-D-glucosaminidase (NAG) normalized for urine creatinine (NAG-Cr). In addition, blood pressure was measured. The measures of gentamicin exposure were cumulative dose (mg/kg) and highest trough plasma concentration (TPC) in mg/L. We used logistic and linear regression and non-parametric kernel regression to analyze the relationship between gentamicin exposure and the urine biomarkers. Results: A total of 222 gentamicin exposed children were included. As neonates, the children were exposed to a median (interquartile range-IQR) cumulative gentamicin dose of 36 (26-42) mg/kg and the median (IQR) TPC was 1.0 (0.7-1.3) mg/L. At follow-up, 15 children (6.8%) had either one abnormal urine biomarker value (13 children) or two abnormal urine biomarker values (2 children). These 17 biomarker values were all marginally above the suggested upper cutoff, and included the following markers; KIM-1 (n = 2), NAC-Cr (n = 5), ACR (n = 6), and PCR (n = 4). All other 207 children had normal sets of all four urine biomarkers. One child had hypertension. There were no differences in gentamicin exposure, gestational age (GA) at birth or birth weight between the group of 15 children with one or two abnormal urine biomarker values compared to the other 207 children who had normal biomarker values. Using different regression analyses, we did not find any association between gentamicin exposure (cumulative dose and/or TPC) and the urine biomarker values. Conclusions: Exposure to an extended-interval, high-dose gentamicin regimen in the neonatal period was not associated with signs of subclinical nephrotoxicity in schoolchildren. We therefore suggest that the gentamicin treatment regimen evaluated in this study is safe in terms of long-term nephrotoxicity. Clinical Trial Registration: ClinicalTrials.gov, identifier: NCT03253614.

The Diagnostic Role of Urinary N-Acetyl-β-D-glucosaminidase (NAG) Activity in the Detection of Renal Tubular Impairment

The kidney function can be assessed by a number of methods. The urinary excretion of enzymes, in particular N-acetyl-β-D-glucosaminidase (NAG), is considered a relatively simple, cheap, fast and non-invasive method in the detection and follow-up of renal tubular function under various conditions. The determination of urinary NAG provides a very sensitive and reliable indicator of renal damage, such as injury or dysfunction due to diabetes mellitus, nephrotic syndrome, inflammation, vesicoureteral reflux, urinary tract infection, hypercalciuria, urolithiasis, nephrocalcinosis, perinatal asphyxia, hypoxia, hypertension, heavy metals poisoning, treatment with aminoglycosides, valproate, or other nephrotoxic drugs. This paper gives an overview of the current use of urinary NAG in the detection of renal injury.

Risk assessment of environmental exposure to heavy metals in mothers and their respective infants

Exposure to heavy metals can cause renal injury, which has been well documented in occupational exposure. Studies of low exposure in the general population, however, are still scarce, particularly for vulnerable populations such as mothers and young children. This study evaluated exposure to heavy metals, and biomarkers of renal function and oxidative stress in 944 lactating mothers and their infants and investigated the role of the interaction between heavy metals and oxidative stress in altering renal function. Mother and infant urine samples were analyzed to measure mercury (Hg), cadmium (Cd), and lead (Pb) concentrations for determining body-burden exposure; N-acetyl-β-d-glucosaminidase (NAG), α₁-microglobulin (α₁-MG), albumin (ALB), and creatinine (Cr) concentrations for determining early renal injury; and 8-hydroxy-2-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) concentrations for determining oxidative stress. The median concentrclearlyations in mothers presented as μg/g Cr (infants as μg/l) for Hg, Cd, and Pb were 0.695 (0.716), 0.322 (0.343), and 3.97 (5.306) respectively. The mothers and their infants had clearly been exposed to heavy metals and had levels higher than the reference values reported for the general populations of USA, Germany, and Canada. Multiple regression analyses clearly demonstrated associations between urinary heavy metals in quartiles and several renal and oxidative biomarkers in mothers and to a lesser extent their infants. ß coefficients for urinary excretions of MDA, 8-OHdG, ALB, α₁-MG, NAG, and Cr in mothers were high in the highest quartile of Hg (1.183-51.29μg/g Cr or 1.732-106.95μg/l), Cd (0.565-765.776μg/g Cr or 0.785-1347.0μg/l), and Pb (6.606-83.937μg/g Cr or 9.459-80.826μg/l), except Pb was not associated with ALB. Infants in the highest Pb quartile (9.293-263.098μg/l) had the highest ß coefficients of urinary excretion of MDA, 8-OHdG, ALB, NAG, and Cr. Significant increasing trend in biomarkers across the quartiles of the three metals was seen in both mothers and infants (p_trend <0.001). A receiver operating characteristic analysis supported the predictive abilities of the four renal biomarkers in discriminating between low versus high metal quartiles. The interaction between heavy metals and oxidative stress contributed to the high excretions of renal biomarkers, but the mechanism remains unclear. These findings add to the limited evidence that low exposure to heavy metals in the general population is associated with alterations in renal function that could eventually progress to renal damage if exposure continues and that children are more susceptible due to the immaturity of their body organs.

Serum NGAL, cystatin C and urinary NAG measurements for early diagnosis of contrast-induced nephropathy in children

AIM

The study investigated a number of biomarkers for the early diagnosis of contrast-induced nephropathy (CIN), which is an important cause of acute kidney injury (AKI).

MATERIAL AND METHODS

The study included 91 children scheduled for elective cardiac angiography and 50 healthy controls. Biomarkers including serum (s) and urinary (u) sodium, serum and u-creatinine, s-cystatin-C, serum neutrophil gelatinase-associated lipocalin (NGAL) and urinary N-acetyl beta glucosaminidase (u-NAG)/creatinine ratio were measured 4 times sequentially in the patients and once in the controls.

RESULTS

The patient group comprised 40 males (44%) and 51 females (56%) while the control group comprised 16 males (32%) and 34 females (68%). Age, gender, s-creatinine, estimated-glomerular filtration rate (eGFR), s-cystatin-C and fractional-excretion of sodium did not differ significantly between the groups. Serum sodium and s-NGAL were found to be lower in the patients than those of in the controls, while their u-NAG/creatinine ratio was found to be higher. Sequential data analysis revealed that s-NGAL and u-NAG/creatinine ratio increased in the first 6 h after radiocontrast media (RCM) administration and decreased at 12 and 24 h. Serum BUN and s-cystatin-C levels also showed a significant difference during the 24-h follow-up. eGFR, s-sodium and s-creatinine levels did not change in the following period. Serum cystatin-C levels revealed a significant negative correlation with eGFR. Administered RCM doses showed a positive correlation only with u-NAG/creatinine ratios.

CONCLUSION

In the first 24 h, s-cystatin-C, s-NGAL and especially u-NAG/creatinine ratio showed promise as biomarkers, but eGFR is not adequate for early diagnosis of CIN. Sequential measurement of biomarkers may contribute to more accurate diagnosis of AKI.

Urine biomarkers of kidney injury among adolescents in Nicaragua, a region affected by an epidemic of chronic kidney disease of unknown aetiology

BACKGROUND

An epidemic of chronic kidney disease (CKD) of non-traditional aetiology has been recently recognized by health authorities as a public health priority in Central America. Previous studies have identified strenuous manual work, agricultural activities and residence at low altitude as potential risk factors; however, the aetiology remains unknown. Because individuals are frequently diagnosed with CKD in early adulthood, we measured biomarkers of kidney injury among adolescents in different regions of Nicaragua to assess whether kidney damage might be initiated during childhood.

METHODS

Participants include 200 adolescents aged 12-18 years with no prior work history from four different schools in Nicaragua. The location of the school served as a proxy for environmental exposures and geographic locations were selected to represent a range of factors that have been associated with CKD in adults (e.g. altitude, primary industry and CKD mortality rates). Questionnaires, urine dipsticks and kidney injury biomarkers [interleukin-18, N-acetyl-d-glucosaminidase (NAG), neutrophil gelatinase-associated lipocalin (NGAL) and albumin-creatinine ratio] were assessed. Biomarker concentrations were compared by school using linear regression models.

RESULTS

Protein (3.5%) and glucose (1%) in urine measured by dipstick were rare and did not differ by school. Urine biomarkers of tubular kidney damage, particularly NGAL and NAG, showed higher concentrations in those schools and regions within Nicaragua that were defined a priori as having increased CKD risk. Painful urination was a frequent self-reported symptom.

CONCLUSIONS

Although interpretation of these urine biomarkers is limited because of the lack of population reference values, results suggest the possibility of early kidney damage prior to occupational exposures in these adolescents.

The Role of Urinary N-acetyl Beta-D-glucosaminidase in Children with Urological Problems

OBJECTIVES

To assess urinary NAG/ urinary creatinine (NAG/ Cr) ratio in patients with urological abnormalities (normal and abnormal ultrasonography) and compare it with normal healthy children.

METHODS

A prospective study was conducted from November 2012 to April 2013. Urine samples were collected from 70 patients with various urological abnormalities, and from 40 healthy control groups, their age range (1 month-13 years). Children who were admitted to Emergency Pediatric department, Children Welfare Teaching Hospital / Medical City Complex, Baghdad, Iraq. The Glomerular filtration rate was in normal range in all of them. Urine samples were tested for NAG by (ELISA, Cusabio, China) while, both Serum creatinine (S-Cr) and urine creatinine (U-Cr) were estimated by Jaffe's kinetic method.

RESULTS

In this study 29% of the patients had normal ultrasonography and 72% abnormal ultrasonography. The current results revealed that NAG/creatinine index was significantly higher in all patients with (vesicoureteral reflux, hydronephrosis and pyelonephritis) in comparison with cystitis.

CONCLUSION

The assessment of urinary NAG could be considered as a useful marker in prediction of the (vesicoureteral reflux, hydronephrosis) .Urinary NAG is elevated in children with pyelonephritis and it can be considered as a further criterion in the diagnosis of upper urinary tract infection.

Urinary N-acetyl-β-D glucosaminidase as a surrogate marker for renal function in autosomal dominant polycystic kidney disease: 1 year prospective cohort study

Background

Renal failure is one of the most serious complications associated with autosomal dominant polycystic kidney disease (ADPKD). To date, early markers have failed to predict renal function deterioration at the early stages. This 1-year prospective study evaluated N-acetyl-β-D-glucosaminidase (NAG) as a new surrogate marker for renal function in ADPKD.

Methods

A total of 270 patients were enrolled in the study, and we measured urinary NAG, β2-microglobulin, neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) prospectively for 1 year to compare their predictive values for renal function.

Results

Baseline urinary NAG/Cr was negatively correlated with estimated glomerular filtration rate (GFR) (r² = 0.153, P < 0.001) and positively correlated with total kidney volume (TKV) (r² = 0.113, P < 0.001). Among other biomarkers, urinary NAG/Cr better discriminated patients with decreased renal function from those with conserved renal function, showing the largest area under the curve (AUC 0.794). Immunohistochemical study revealed strong staining along the cyst-lining epithelial cells as well as the nearby compressed tubular epithelial cells. However, both single and repeated measurements of urinary NAG/Cr failed to predict renal function decline in 1 year.

Conclusions

Urinary NAG/Cr may be a useful surrogate marker for renal function in ADPKD patients.

Effect of mercury (Hg) dental amalgam fillings on renal and oxidative stress biomarkers in children

We examined the effect of mercury (Hg) associated with dental amalgam fillings on biomarkers of renal and oxidative stress in children between the ages of 5-15.5 years. Urine samples were analyzed for N-acetyl-β-D-glucosaminidase (NAG), α(1)-microglobulin (α(1)-MG), β(2)-microglobulin (β(2)-MG), retinol binding protein (RBP), albumin (ALB), 8-hydroxy-2-deoxyguanosine (8-OHdG) and malondialdehyde (MDA). The level of urinary Hg (UHg-C) was calculated as μg/g creatinine. Multiple regression analyses revealed that the excretion of urinary NAG was significantly associated with the presence of dental amalgam fillings (β=0.149, P=0.03) and the levels of UHg-C (β=0.531, P=0), with an interaction between the two (P=0). The increase in urinary NAG in relation to UHg-C levels had a dose-effect pattern. The lowest observed effect was seen at UHg-C levels above 1.452 μg/g creatinine, which is lower than previously reported. In contrast, α(1)-MG was negatively associated with the presence of dental amalgam fillings (β=-0.270, P=0), but positively with UHg-C levels (β=0.393, P=0). There were 7 children without, and one child with, dental amalgam fillings with urinary α(1)-MG levels above the reference limit of >7 mg/g creatinine. Even though α(1)-MG seems to be a reliable biomarker for early changes in renal functions, it might exert its effect only at a higher level of exposure. An inverse relationship was also observed between urinary 8-OHdG levels and the presence of dental amalgam fillings. This might suggest that the dental amalgam does not increase DNA damage but reduces the capacity to repair DNA, leading to lower urinary excretion of 8-OHdG. On the other hand, we found that Hg affected the excretion of urinary 8-OHdG in a dose-related pattern that was mostly associated with long-term exposure to low Hg levels. Urinary NAG levels were positively associated with urinary MDA levels (β=0.516, P=0) but not with 8-OHdG (β=0.134, P=0.078) after adjustment for potential confounders. Both UHg-C and the presence of dental amalgam fillings remained predictors of the NAG model. Our data provide evidence that low exposure to Hg from dental amalgam fillings exerts an effect on kidney tubular functions in children. Oxidative stress may have played a role in this mechanism. The results of this study would also suggest that urinary NAG is the most sensitive of all the investigated renal biomarkers. These results should be confirmed with further investigation.

Evaluation of the optimal frequency of and pretreatment with shock waves in patients with renal stones

Purpose

Many studies have been carried out to increase the success rate of shock wave lithotripsy (SWL) and to reduce renal injury. We investigated the success rate after one session as well as urine N-acetyl-β-d-glucosaminidase (NAG) levels for the evaluation of renal injury according to shock wave frequency and pretreatment with low-energy shock waves during SWL.

Materials and Methods

The study targeted 48 patients with renal stones who had undergone SWL. Patients were sequentially allocated into four groups according to shock wave frequency (60 or 120 shocks/min) and whether pretreatment had occurred. We documented total SWL operating number, success rate after first SWL, urine NAG, compliance, and the total cost for each patient.

Results

There were 32 males and 16 females with an average age of 51.6 years. The average stone size was 7.06 mm, and there was no significant difference in stone size between the groups. The data showed that patients treated with a frequency of 60 shocks/min had a lower mean number of SWL sessions, 1.36 sessions for 60 shocks/min and 2.0 sessions for 120 shocks/min, respectively, which was statistically significant (p<0.05). When comparing NAG/creatinin ratios before and after SWL between those with and without pretreatment, there was no significant difference according to pretreatment (p=0.406).

Conclusions

SWL treatment at a frequency of 60 shocks/min yielded better outcomes, such as a lower number of SWL sessions, and had an increased success rate compared with SWL at 120 shocks/min. On the other hand, pretreatment did not impact renal injury. Therefore, SWL treatment at a frequency of 60 shocks/min could improve treatment efficacy more than that for SWL at 120 shocks/min.

Enzymuria determination in children treated with aminoglycosides drugs

Although aminoglycosides antibiotics are used in children and adult commonly, they have serious side effects such as nephrotoxicity and ototoxicity. In clinical practice, for renal function, the levels of serum creatinine and blood urea nitrogen routinely are measured. Since these parameters have limitations such as unreliability, insensitivity, and nonspecificity, the rapid assessment of renal function based on these patients is very important. Increase in N-acetyl-β-D-glucosaminidase (NAG), a hydrolytic lysosomal enzyme, suggests proximal tubular cell damage. In this study, 32 children aged 2 months through 2 years, treated with gentamicin and amikacin for suspected infections at the pediatric ward of Alborz hospital from September 2006 to February 2007, were enrolled. Serum and fresh urine before and after drug infusion were obtained on the 1st, 3rd, and 5th days of antibiotic treatment. Serum urea and creatinine with urinary creatinine, albumin, NAG, lactate dehydrogenase (LDH) and alkaline phosphatase (AP) activity were then determined. A statistically significant increase in urinary NAG, LDH, and AP on 5th day was found compared with before gentamicin administration ( P < 0.001, P < 0.01, P < 0.05, respectively). The urinary NAG activity may be a useful indicator of renal injury in children treated with aminoglycosides drugs compared with other routine clinical indicators.

Determination of urinary enzymes as a marker of early renal damage in diabetic patients

Diagnosis of diabetic nephropathy in the early stages is very important since there are no clinical signs or symptoms. Urinary N-acetyl-beta-D-glucosaminidase (NAG) excretion has been recommended as a tubular dysfunction marker that elevates before other markers, such as microalbuminuria and a decrease in creatinine clearance. In this study, we compared excretion of urinary enzymes with other markers that are used routinely in diabetic nephropathy assessment. Urinary NAG, lactate dehydrogenase (LDH), alkaline phosphatase (AP) activities, urea, creatinine, and albumin, with levels of serum glucose and creatinine and whole blood glycosylated hemoglobin (HbA1c) were measured in 32 diabetes mellitus patients and 25 healthy subjects (controls). Notably, urinary NAG, AP, LDH excretion, and microalbuminuria in the diabetic patients group were significantly increased compared to those in the control groups (P<0.001, P<0.05, P<0.01, and P<0.01, respectively). Meanwhile, our results showed that the urinary NAG excretion had the highest sensitivity and specificity (100% and 87.5%, respectively) compared to other markers. We showed that measuring urinary NAG excretion could be useful for the assessment of renal failure in diabetes mellitus patients and confirmed the use of NAG as a routine screening test.

Increased urinary N-acetyl-beta-D-glucosaminidase activity in children with hydronephrosis

OBJECTIVE

Hydronephrosis leads to deterioration of renal function. As urinary N-acetyl-beta-D-glucosaminidase (U-NAG) activity is considered a sensitive marker of renal tubular impairment, our aim was to measure U-NAG in children with hydronephrosis and to look for a relationship among selected clinical parameters.

MATERIALS AND METHODS

We studied 31 children (22 boys and 9 girls, mean age 2.3 +/- 2.5 years) with hydronephrosis grade 1-4 that had U-NAG/creatinine ratio (U-NAG/Cr) measured.

RESULTS

The U-NAG/Cr was significantly higher in patients with hydronephrosis compared to reference data (p = 0.002). There was no difference in U-NAG/Cr between children with unilateral and bilateral hydronephrosis (p = 0.51). There was no significant difference in U-NAG/Cr between children with grades 1-3 (pooled data) and grade 4, respectively (p = 0.89). There was no correlation between U-NAG/Cr and the grade of hydronephrosis (r = 0.01).

CONCLUSIONS

U-NAG/Cr is increased in children with hydronephrosis grade 1-4, and there is no relationship with the grade of hydronephrosis. U-NAG is a useful marker of renal tubular dysfunction, however its relationship with the degree of kidney damage in patients with hydronephrosis should be considered as doubtful.

Bone mineral density and urinary N-acetyl-beta-D-glucosaminidase activity in paediatric patients with idiopathic hypercalciuria

BACKGROUND

Idiopathic hypercalciuria (IH) is defined as hypercalciuria that persists after correction of dietary inbalances and has no detectable causes. Patients with IH have a higher prevalence of osteoporosis. Defective reabsorption of calcium by the renal tubule is considered a likely mechanism of IH. N-acetyl-beta-D-glucosaminidase (NAG) is a lysosomal enzyme that is a very sensitive marker of renal tubular impairment.

METHODS

Fifteen patients (nine boys and six girls, mean age 12.4 +/- 4.0 years) with IH (urinary calcium excretion >0.1 mmol/kg per 24 h) had their bodyweight, height, body mass index (BMI), urinary NAG/creatinine ratio (U-NAG/Cr) and 24-h urinary calcium excretion (U-Ca/24 h) assessed. L1-L4 bone mineral density (BMD) was measured by dual energy X-ray absorptiometry and volumetric BMD (BMDvol) was calculated. The obtained results were expressed as Z-scores.

RESULTS

The values of basic anthropometric parameters did not differ significantly from the values of the reference population and there was a tendency to short stature, which did not reach statistical significance (P = 0.08). The values of calciuria and U-NAG/Cr were significantly higher while BMD was significantly lower when compared to the reference values (P < 0.0006, P < 0.006 and P < 0.001, respectively). Inverse and significant correlations were found between U-Ca/24 h and BMD, U-Ca/24 h and body height, and U-Ca/24 h and BMDvol (r = -0.64 and -0.70, respectively, P < 0.01; r = -0.55, P < 0.05), while there was no correlation between U-NAG/Cr and U-Ca/24 h, nor between BMD and weight or BMD and BMI.

CONCLUSION

Tubular impairment is highly probable in children with IH, but there is a poor relationship with the degree of calcium leakage. Idiopathic hypercalciuria should be considered as a risk factor for stunted growth and low bone mass.