Reflections on TRP and TP/GFR in the definition of renal phosphate loss: conceptual review.

BACKGROUND: Fractional tubular reabsorption of phosphate (TRP) has been used for over 60 years to establish the existence of renal phosphate loss. It is a parameter of corrected volume per decilitre of glomerular filtration rate (GFR). Later, a mass parameter per dl GFR called TP/GFR (tubular PO4 reabsorption per dl GFR) was devised which some authors have sought to substitute for TRP. The aim of the present work is to attempt to demonstrate that TRP and TP/GFR are similar parameters and, in certain aspects, TRP is more effective for diagnosis. METHODS: Data were gathered on the metabolism of phosphate corresponding to a group of healthy children without hypophosphatemia (n = 47), a group of patients with idiopathic hypercalciuria (n = 27), and ten patients diagnosed with X-linked hypophosphatemia (XLH). The TRP, the TP/GFR, and the percent tubular reabsorption of phosphate were calculated. RESULTS: All the patients with XLH presented TRP values lower than 95 ml/dl GFR and of TP/GFR equal to or lower than 2.8 mg/dl GFR. In the total sample, a direct correlation was observed between TRP and TP/GFR (r = 0.65; p = 0.01). The TRP and the percent tubular reabsorption of phosphate values were the same in the three groups (r = 1; p = 0.01). CONCLUSIONS: TRP and TP/GFR are similar parameters. TRP is more effective than TP/GFR given that in renal hypophosphatemia it is always below 95% and above 95% in reduced phosphatemia and normal kidney proximal tubular function. There is no solid reason for using TP/GFR rather than TRP. A higher resolution version of the Graphical abstract is available as Supplementary information.

Blood Lead Level in a Paediatric Population of South-Eastern Spain and Associated Risk Factors.

OBJECTIVE: To determine blood lead levels (BLL) in a healthy paediatric population and to analyse related sociodemographic, dietary and haematological factors. METHODS: A cross-sectional study was made of 1427 healthy subjects aged 1-16 years from the city of Almería (south-eastern Spain). BLL, iron parameters and erythropoietin were determined, and sociodemographic and dietary data obtained. The study paramateters was analyses in BLL toxic and BLL no toxic group by multiple logistic regression. RESULTS: The mean BLL was 1.98 ± 1.1 µg/dL (95% CI:1.91-2.04). For 5.7% of the population, mean BLL was 2-5 µg/dL, for 2.1% it was >5 µg/dL and for 0.15% it was >10 µg/dL. Multivariate analysis showed that immigrant origin (OR:11.9; p < 0.0001), low level of parental education (OR:4.6; p < 0.02) and low dietary iron bioavailability (OR: 3.2; p < 0.02) were all risk factors for toxic BLL. Subjects with toxic and non-toxic BLL presented similar iron and erythropoiesis-related parameters, except erythrocyte protoporphyrin, which was significantly higher in the BLL >5 µg/dL group. CONCLUSIONS: BLL and the prevalence of toxic BLL in healthy subjects aged 1-16 years living in south-eastern Spain are low and similar to those found in other developed countries. The factors associated with toxic BLL are immigrant origin, low level of parental education and dietary iron deficiency. The toxicity of BLL was not related to changes in the analytical parameters studied.

Status of folate in healthy children in Almeria.

The objective of this study is to establish reference values for folic acid in a healthy population of children aged 4-11 years and to examine related epidemiological, dietary and analytical factors. A cross-sectional study of 658 healthy children aged 4-11 years was made. Epidemiological, socioeconomic and dietary variables were analysed, the BMI Z-score was obtained, levels of serum folate and serum vitamin B12 were determined and haematological, iron status and erythropoietic activity parameters were examined. The study data were analysed by non-parametric tests and linear multiple regression. The mean folate value was 8.6 ± 4.6 ng/mL (95% reference interval: 2.8-20 ng/mL). A level < 3 ng/mL (5th percentile) was considered as folate deficiency (4.6% of subjects). No child reported symptoms related to this deficiency. Folate values were significantly lower with age (p < 0.01), low NSE and low parental educational level (p: 0.0001). No relationship was found between folates and the analytical variables. According to multivariate linear regression, the variables significantly associated with serum folate were age, socioeconomic level and vitamin B12.Conclusions: Serum folate levels in healthy school children are described. Age, socioeconomic level and serum vitamin B12 are factors associated with folate status. Specific cut-off values for a paediatric population should be defined. What is Known: • Folic acid is an essential micronutrient for optimal growth and development; its deficit is associated with adverse health effects. • The studies on their status and deficit are not comparable due to a lack of agreement on appropriate indicators and reference values. What is New: • This study reports the levels of serum folate in a large population of healthy schoolchildren, with strict inclusion criteria in a developed country and identifies the associated sociodemographic, dietary and analytical (vitamin B12, iron parameters and erythropoietic activity) factors, avoiding potential confusion.

Can acetazolamide be used to treat diseases involving increased bone mineral density?

Sclerosing bone dysplasias are a series of clinically and genetically heterogeneous diseases characterized by functional failure of the osteoclasts in bone resorption, leading to an excessive amount of bone mineral density (BMD) which could have serious clinical consequences. We treated three children affected with seriously high levels of BMD with acetazolamide, with the intention of inducing metabolic acidosis, thus increasing bone resorption and reducing BMD. All our patients tolerated and followed the treatment well and the clinical response was satisfactory in all cases.

Agenesia renal unilateral. Nuevos argumentos acerca de la relación genética entre la urolitiasis y las malformaciones renales / Unilateral renal agenesis. New arguments about the genetic relationship between kidney malformations and urolithiasis

ANTECEDENTES: En escasos trabajos previos, se ha comunicado que puede observarse la presencia de hipercalciuria en pacientes portadores de algunos tipos de CAKUT como estenosis pieloureteral, reflujo vesicoureteral o quistes renales simples. Además, se ha descrito una prevalencia mayor de hipercalciuria y/o urolitiasis en los miembros de las familias de esos niños con algunos tipos de CAKUT, en comparación con la población en general. El presente estudio se llevó a cabo para averiguar si los niños con agenesia renal unilateral (ARU) tienen las características descritas anteriormente en otros tipos de CAKUT. MÉTODOS: En un estudio descriptivo y multicéntrico se determinó la prevalencia de hipercalciuria, hipocitraturia y urolitiasis en 67 niños (43 hombres y 24 mujeres) con ARU y sus familias. RESULTADOS: En 26 niños (38,8%) se observaron las dos anomalías metabólicas que favorecen la formación de cálculos renales distribuidos de la siguiente manera: hipercalciuria en 16, hipocitraturia en 9 y tanto hipercalciuria como hipocitraturia en 1. Ocho niños (11,9%) padecieron un cólico renal durante el tiempo total de seguimiento. Una historia familiar de litiasis urinaria se encontró en 42/67 de los niños (62,7%): en familiares de primer grado en 12 de ellos, en familiares de segundo grado en 15 y en ambos grados de familiares en los otros 15. En contraste, en el grupo de control histórico, solamente en 28,1% de las familias, al menos, un miembro había tenido urolitiasis. CONCLUSIÓN: Nuestros resultados muestran que la prevalencia de la hipercalciuria y/o hipocitraturia en pacientes pediátricos con ARU es mayor que en la población general. Asimismo, la prevalencia de urolitiasis en las familias de estos niños es también mayor que en la población general

BACKGROUND: In few previous studies, it has been reported that hypercalciuria is associated with some types of congenital anomalies of the kidney and urinary tract (CAKUT), namely ureteropelvic junction obstruction, vesicoureteral reflux or simple renal cysts. In addition, one higher prevalence of hypercalciuria and/or urolithiasis has been described in their family members compared to the general population. This study was carried out to find out whether children with unilateral renal agenesis (URA) have these features previously described in other CAKUT types. METHODS: In a descriptive and multicenter study we studied the prevalence of hypercalciuria, hypocitraturia and urolithiasis in 67 children (43 males and 24 females) with URA and their families. RESULTS: The two metabolic anomalies that promote stone formation were observed in 26 children (38.8%), distributed as follows: hypercalciuria in 16, hypocitraturia in 9, and both hypercalciuria and hypocitraturia in 1. Eight children (11.9%) suffered renal colic during follow-up. Familial history of urolithiasis was found in 42/67 children (62.7%): in 12 of the first-degree relatives, in 15 of the second degree relatives and in 15 patients both in the first-degree as in their second degree relatives. In contrast, in historic control group, only in 28.1% of families at least one member had urolithiasis. CONCLUSION: Our results show that the prevalence of hypercalciuria and/or hypocitraturia is greater in pediatric patients with URA than in the general population. Likewise, the prevalence of urolithiasis in the families of these children is also higher than that in the general population

[Unilateral renal agenesis. New arguments about the genetic relationship between kidney malformations and urolithiasis]. / Agenesia renal unilateral. Nuevos argumentos acerca de la relación genética entre la urolitiasis y las malformaciones renales.

BACKGROUND: In few previous works, it has been reported that hypercalciuria is associated with some types of CAKUT, namely ureteropelvic junction obstruction, vesicoureteral reflux or simple renal cysts. In addition, one higher prevalence of hypercalciuria and/or urolithiasis has been described in their family members compared to the general population. This study was carried out to find out whether children with unilateral renal agenesis (URA) have these features previously described in other CAKUT types. METHODS: In a descriptive and multicenter study we studied the prevalence of hypercalciuria, hypocitraturia and urolithiasis in 67 children (43 males and 24 females) with URA and their families. RESULTS: The two metabolic anomalies that promote stone formation were observed in 26 children (38.8%), distributed as follows: hypercalciuria in 16, hypocitraturia in 9, and both hypercalciuria and hypocitraturia in 1. Eight children (11.9%) suffered renal colic during follow-up. Familial history of urolithiasis was found in 42/67 children (62.7%): in 12 of the first-degree relatives, in 15 of the second degree relatives and in 15 patients both in the first-degree as in their second degree relatives. In contrast, in historic control group, only in 28.1% of families at least one member had urolithiasis. CONCLUSION: Our results show that the prevalence of hypercalciuria and/or hypocitraturia is greater in pediatric patients with URA than in the general population. Likewise, the prevalence of urolithiasis in the families of these children is also higher than that in the general population.

Prevalencia de sobrepeso y obesidad en niños y adolescentes de 2 a 16 años / Prevalence of overweight and obesity in children and adolescents aged 2-16 years

Objetivos Calcular la prevalencia de obesidad y sobrepeso en niños y adolescentes de nuestra ciudad e investigar los factores asociados. Sujetos y métodos Estudio transversal de 1.317 niños y adolescentes de 2 a 16 años. Mediante muestreo probabilístico polietápico se seleccionaron 3 grupos: 411 de 12 a 16, 504 de 6 a 12 y 402 de 2 a 6 años. Se les calculó el índice de masa corporal y se definió obesidad y sobrepeso según la International Obesity Task Force. Se realizó un cuestionario de consumo de alimentos y de características clínicas y sociodemográficas. Los resultados se expresan como porcentajes (intervalos de confianza al 95%). Mediante regresión logística múltiple se estudió la asociación entre exceso de peso (obesidad y sobrepeso) y las distintas variables, calculando la odds ratio (OR) ajustada. Resultados El 9,5% (8,0-11,0) de los niños y adolescentes de 2 a 16 años son obesos y 22,4% (23,3-24,6) tienen sobrepeso. En el grupo de 12 a 16 años, el 8,5% (5,9-11,2) son obesos y el 20,5% (16,7-24,3) tienen sobrepeso, en el grupo de 6 a 12 años el 11,6% (8,9-14,3) y el 31,0% (27,0-35,0) y en el de 2 a 6 años el 8,0% (5,4-10,6) y el 13,6% (10,3-16,9), respectivamente. Se asocian con el exceso de peso la edad (OR 1,21; p<0,001), la obesidad materna (OR 10,99; p = 0,008), el peso al nacer mayor de 4kg (OR 2,91; p = 0,002) y la lactancia artificial exclusiva (OR 1,82; p = 0,005).Conclusión La obesidad y el sobrepeso infantil y juvenil son problemas extraordinariamente prevalentes en nuestra ciudad (AU)

Objectives To estimate the prevalence of obesity and overweight in children and adolescents in our city and to investigate the associated factors. Subjects and methods A cross-sectional study of 1317 children and adolescents aged 2-16 years. Multistage probability sampling was used to select three groups of subjects: 411 aged 12 to 16 years, 504 aged 6 to 12 years, and 402 aged 2 to 6 years. Body mass index was calculated, and obesity and overweight were diagnosed using the threshold levels of the International Obesity Task Force for children and adolescents. Parents were asked about eating habits, health, social, and demographic aspects. Results are given as percentages (95% confidence interval). The relationship between obesity and overweight and the different variables was studied using multiple logistic regression. The adjusted odds ratio (OR) was calculated. Results Among children and adolescentes aged 2-16 years, 9.5% (8.0%-11.0%) were obese and 22.4% (23.3%-24.6%) were overweight. Of subjects aged 12-16 years, 8.5% (5.9%-11.2%) were obese and 20.5% (16.7%-24.3%) were overweight. In the groups aged 6-12 years and 2-6 years, rates of obesity and overweight were 11.6% (8.9% -14.3%) and 31.0% (27.0-35.0) and 8.0% (5.4%-10.6%) and 13.6% (10.3%-16.9%) respectively. Obesity or overweight was associated to age (OR 1.21; P <0.001), maternal obesity (OR 10.99; P= 0.008), a birthweight higher than 4kg (OR 2.91; p 0.002), and formula feeding (OR 1.82; P= 0.005).Conclusion Obesity and overweight in children and adolescents are highly prevalent problems in our city (AU)

Prevalence of overweight and obesity in children and adolescents aged 2-16 years.

OBJECTIVES: To estimate the prevalence of obesity and overweight in children and adolescents in our city and to investigate the associated factors. SUBJECTS AND METHODS: A cross-sectional study of 1317 children and adolescents aged 2-16 years. Multistage probability sampling was used to select three groups of subjects: 411 aged 12 to 16 years, 504 aged 6 to 12 years, and 402 aged 2 to 6 years. Body mass index was calculated, and obesity and overweight were diagnosed using the threshold levels of the International Obesity Task Force for children and adolescents. Parents were asked about eating habits, health, social, and demographic aspects. Results are given as percentages (95% confidence interval). The relationship between obesity and overweight and the different variables was studied using multiple logistic regression. The adjusted odds ratio (OR) was calculated. RESULTS: Among children and adolescents aged 2-16 years, 9.5% (8.0%-11.0%) were obese and 22.4% (23.3%-24.6%) were overweight. Of subjects aged 12-16 years, 8.5% (5.9%-11.2%) were obese and 20.5% (16.7%-24.3%) were overweight. In the groups aged 6-12 years and 2-6 years, rates of obesity and overweight were 11.6% (8.9% -14.3%) and 31.0% (27.0-35.0) and 8.0% (5.4%-10.6%) and 13.6% (10.3%-16.9%) respectively. Obesity or overweight was associated to age (OR 1.21; P<0.001), maternal obesity (OR 10.99; P= 0.008), a birthweight higher than 4kg (OR 2.91; p 0.002), and formula feeding (OR 1.82; P= 0.005). CONCLUSION: Obesity and overweight in children and adolescents are highly prevalent problems in our city.