Sodium Excretion In Children Research Articles

Does the Mediterranean Dietary Pattern Promote Lower Sodium Urinary Excretion in Children?

An adequate sodium intake is related to various health benefits. Parallelly, the Mediterranean diet (MD) is a dietary pattern known for its many positive impacts on health. Nonetheless, the association between adherence to the MD and sodium urinary excretion is scarce, even more in children. This study aimed to assess the association between MD adherence and the excretion of sodium, as a proxy of intake. This cross-sectional analysis comprised 295 children (46.8% females, aged 7-11 years, mean age: 8.53 ± 0.73 years) from 20 schools within Porto, Portugal. MD adherence was evaluated utilizing the alternate Mediterranean score (aMED). Higher scores denote a healthier dietary pattern (0-8). Sodium excretion was estimated by 24-h urine collection. The association between adherence to MD and Na excretion was estimated by logistic regression, adjusting for confounders. Children in the higher sodium excretion group had a higher intake of legumes, a higher body mass index and parents with lower education levels compared to children in the lower sodium excretion group. In logistic regression analysis, sodium urinary excretion was not associated with higher MD adherence, even after adjustment for confounders. High MD adherence could not be associated with lower sodium excretion in children.

The Severity of Obesity Promotes Greater Dehydration in Children: Preliminary Results.

The state of hydration of the body depends on the balance between the amount of water and salt consumed and excreted (the urinary extraction of excess sodium requires water). Inappropriate nutrition, particularly consuming too much processed food, causes obesity in children and additionally causes excessive sodium consumption, thus increasing the risk of excessive water loss. The aim of this study was to assess the hydration status of children with obesity and the relation between hydration, body composition, urinary sodium extraction, and nutrient intake. The study group consisted of 27 patients with obesity, with a mean age of 12.89 ± SD 2.79. Each patient's height, weight, body composition (electrical bioimpedance (BIA)), diet (7-day record), and biochemical tests were assessed. The hydration status was assessed using 24-hour urine collection, 24-hour urine osmolality, and an ultrasound of the vena cava (IVC/Ao index). Overall, 55% of children (n = 15) had urine osmolality values above 800 mOsm/kgH2O, which indicates significant dehydration, and 53% (n = 14) were dehydrated, based on the IVC/Ao index. Children with obesity and dehydration had a significantly higher BMI (31.79 vs. 27.32; p = 0.0228), fat mass percentage (37.23% vs. 30.07% p = 0.0051), and fat mass in kg (30.89 vs. 20.55; p = 0.0158), and significantly higher sodium intake from their diet (3390.0 mg vs. 2921.0 mg; p = 0.0230), as well as their sodium/potassium ratio (2.4 vs. 2.0; p = 0.0043). The 24-hour urinary sodium excretion and osmolality values were directly related to fat-mass percentage and fat-mass (in kg) in a simple linear correlation analysis. Our preliminary results confirm that obesity is related to dehydration. The overall high sodium excretion in children with obesity indicates an excessive salt intake along with low potassium intake, which is a significant predictor of dehydration, regardless of the total water intake (TWI).

Urine Spot Samples Can Be Used to Estimate 24-Hour Urinary Sodium Excretion in Children

The gold standard to assess salt intake is 24-h urine collections. Use of a urine spot sample can be a simpler alternative, especially when the goal is to assess sodium intake at the population level. Several equations to estimate 24-h urinary sodium excretion from urine spot samples have been tested in adults, but not in children. The objective of this study was to assess the ability of several equations and urine spot samples to estimate 24-h urinary sodium excretion in children. A cross-sectional study of children between 6 and 16 y of age was conducted. Each child collected one 24-h urine sample and 3 timed urine spot samples, i.e., evening (last void before going to bed), overnight (first void in the morning), and morning (second void in the morning). Eight equations (i.e., Kawasaki, Tanaka, Remer, Mage, Brown with and without potassium, Toft, and Meng) were used to estimate 24-h urinary sodium excretion. The estimates from the different spot samples and equations were compared with the measured excretion through the use of several statistics. Among the 101 children recruited, 86 had a complete 24-h urine collection and were included in the analysis (mean age: 10.5 y). The mean measured 24-h urinary sodium excretion was 2.5 g (range: 0.8-6.4 g). The different spot samples and equations provided highly heterogeneous estimates of the 24-h urinary sodium excretion. The overnight spot samples with the Tanaka and Brown equations provided the most accurate estimates (mean bias: -0.20 to -0.12 g; correlation: 0.48-0.53; precision: 69.7-76.5%; sensitivity: 76.9-81.6%; specificity: 66.7%; and misclassification: 23.0-27.7%). The other equations, irrespective of the timing of the spot, provided less accurate estimates. Urine spot samples, with selected equations, might provide accurate estimates of the 24-h sodium excretion in children at a population level. At an individual level, they could be used to identify children with high sodium excretion. This study was registered at clinicaltrials.gov as NCT02900261.

Salt intake in children 10–12 years old and its modification by active working practices in a school garden

The aim of the study was to evaluate the 24-h urinary sodium excretion in children of 10-12 years at a school in the north of Portugal and to examine the influence on salt intake and blood pressure of three different educational interventions for 6 months. Blood pressure (BP) and sodium excretion in 24-h urinary samples (UNa) validated with urinary creatinine were measured in 155 children 10-12 years old belonging to nine classes at baseline and after 6 months of three educational interventions in students from three classes each after parents consent was obtained. Interventions consisted in no additional action [control (CTR)], weekly lessons about the dangers of high salt intake [Theoretical (THEOR)] and both lessons and working practices in the school garden of planting, collection of herbs for salt substitution at home [practical (PRACT)]. At baseline 139 students (76 girls and 63 boys) were eligible showing average 24-h UNa of 132±43 mmol/24 h (mean salt intake of 7.8±2.5 g per day) and BP of 118/62 (13/9) mmHg that did not correlate to each other. At the end of the study, versus baseline, BP decreased by 8.2/6.5 mmHg in CTR (n=31), by 3.8/0.6 mmHg in THEOR (n=43) and by 3.5/0.7 mmHg in PRACT (n=53) and salt intake was reduced by 0.4±2.4 g per day in CTR, by 0.6±3.2 g per day in THEOR and by 1.1±2.5 g per day in PRACT. It was observed that salt intake variation was not independent of the group (CRT, THEOR and PRACT) (χ, 9.982, P=0.041). Salt intake was significantly reduced only in the PRACT group (1.1 g per day) and in the PRACT group the percentage of children who reduced salt intake by at least 1g per day from baseline to the end of the study was significantly higher (50.9%) than that of the other groups, THEOR, 48.8% and CTR, 32.2%. Our data indicates that children 10-12 years old have a high salt intake that is well above the proposed recommendations and that a strategy based on theoretical and practical education may achieve in some children an important reduction in daily salt intake which, if maintained over time, may assume important public health implications. These results suggest that in those children a more complete theoretical and practical intervention is more productive and efficient towards reduction of salt intake than single theoretical or no intervention.

Response to Salt Intake in Children: Increasing Concerns?

We are very grateful to Schreuder et al1 for providing valuable new information on salt intake measured by 24-hour urinary sodium excretion in children in the Netherlands. Their results clearly show that salt intake in children is unnecessarily high and, if expressed as for an adult with a 70-kg body weight, salt intake would be 12 g per day in 1993–1995 and increased to 16 g per day by 2003–2005. It is likely that, in most developed countries, children’s salt …

Reduction of blood pressure with calcium and potassium supplementation in children with salt sensitivity: a 2-year double-blinded placebo-controlled trial

An investigation of the reductive effect of blood pressure and increment of urinary sodium excretion with calcium and potassium supplementation in children with sodium sensitivity is conducted. In total of 261 school children who had completed a 2-year double-blinded, placebo-controlled trial with calcium and potassium supplementation salt sensitivity, with a salt volume expansion and contraction protocol, was determined. The results showed that in children with salt sensitivity, the increase in blood pressure in the supplementary group was lower by 4.3/4.8 mmHg than that in the placebo group (P<0.05), while no significant change was found between the supplementary group and placebo group in children with nonsalt sensitivity. With calcium and potassium supplementation, the night urinary sodium excretion in children with salt sensitivity was significantly increased (P<0.01), and it is negatively correlated with the increase in blood pressure. It was suggested that a moderate increase of calcium and potassium intake in children with salt sensitivity, through interaction with sodium, can promote urinary sodium excretion and may play contribute to the prevention of hypertension.

Obesity influences the urinary sodium excretion in children and adolescents

Obesity influences the urinary sodium excretion in children and adolescents

Current and birth weights exert independent influences on nocturnal pressure-natriuresis relationships in normotensive children.

The objective was to study the impact of birth weight on the relationship between ambulatory blood pressure and urinary sodium excretion in children and adolescents. The study included 134 healthy children (61 boys), all Caucasians, who were born at term after a normotensive pregnancy. For each subject, a 24-hour ambulatory blood pressure monitoring and a complete urine collection were simultaneously performed according to the protocols designed. Average ambulatory blood pressure (BP) and the urinary excretion rates for sodium, potassium, and creatinine were calculated separately for 24-hour, awake, and sleep periods defined by a mini-diary. The excretion rate of sodium during sleep time was positively correlated with ambulatory systolic BP; such a positive relationship was not found for waking hours. Consequently, the impact of birth weight on the relationship between blood pressure and the urinary sodium excretion rate was analyzed during sleeping hours. Stepwise multiple regression analysis shows that although current weight was the strongest predictor for the sodium excretion rate during sleep (P<.001), there was also an independent significant direct relationship for birth weight (P<.04) after controlling for age, sex, and the average of systolic BP during sleep. Adjusted for current weight, a significant difference in the regression slopes relating urinary sodium excretion rate and systolic BP during sleep exists between children in the lowest (<3.100 kg) and the highest tertiles (>3.500 kg) of birth weight (P<.02). Differences in sodium excretion rates, adjusted for current weight, between the two extreme tertiles of birth weight became significant at the highest systolic BP (P<.04). The children who had the lowest birth weight tended to excrete less sodium during sleep. The results of the present study show a blunted pressure natriuresis curve in children and adolescents with the lowest birth weight. Whether this abnormal renal sodium handling may be present as an initial or as an intermediate mechanism leading to higher BP values must be assessed in additional studies.

Urinary Volume in Children with Urolithiasis

Urinary volume in 24-hour urine collections was examined in 50 children with hypercalciuria and urolithiasis or hematuria, 12 with idiopathic calcium oxalate urolithiasis and 36 healthy children. Urinary volume was 22.2 ± 2.0ml. per kg. per day in healthy children and 25.4 ± 2.0ml. per kg. per day in children with hypercalciuria, and it was similar in children with absorptive and renal hypercalciuria, and significantly lower in children with idiopathic calcium oxalate urolithiasis (12.2 ± 1.4ml. per kg. per day, p less than 0.001 from controls and children with hypercalciuria). Volume was not statistically different in hypercalciuric children with and without urolithiasis. Urinary sodium excretion in children with idiopathic calculi was not statistically different from controls. Urine osmolality was similar among the groups. Urinary volume represents a risk factor in children with idiopathic calcium oxalate urolithiasis, and increased fluid intake should be emphasized in such patients.

Aldosterone excretion rates in children and adults during sleep.

The present study undertook to examine aldosterone excretion during sleep as an integrated measurement of aldosterone production. A 24-hour urine collection was divided into awake and sleep fractions. Urinary aldosterone and electrolyte excretion were measured in 26 healthy children (mean age, 8.9 +/- 1.9 [SD] years) and 28 adults (mean age, 29.9 +/- 9.5 years). Aldosterone excretion in children was 5.6 +/- 3.9 (SD) micrograms/g creatinine during the awake period, which was significantly different from the 3.9 +/- 4.1 micrograms/g creatinine value recorded during sleep (p less than 0.002). In adults, awake aldosterone excretion was significantly greater than that during sleep; 4.9 +/- 2.7 versus 3.2 +/- 1.6 micrograms/g creatinine (p less than 0.001). Sleep aldosterone excretion values were highly correlated with the corresponding 24-hour aldosterone excretion values (r = 0.85, p less than 0.001) in children and in adults (r = 0.64, p less than 0.001). Sleep aldosterone excretion was correlated with 24-hour potassium excretion (p less than 0.02) only in children. Sleep aldosterone excretion correlated with neither sleep nor 24-hour sodium excretion in children or adults. Sleep electrolyte excretion rates were highly correlated with 24-hour excretion rates in both children and adults. Dexamethasone, 1 mg, administered the night before to suppress the normally high morning levels of endogenous adrenocorticotropic hormone, had no discernible effect on sleep aldosterone excretion. These results indicate that measurement of aldosterone excretion in an easily collected sleep urine sample provides a reliable index of aldosterone production in children and adults.

Effect of inheritance and stress on the diurnal excretion of sodium and potassium in young people with and without a family history of hypertension.

1. The diurnal excretion of sodium and potassium was observed in young people, with and without a genetic predisposition to hypertension, both in the presence and absence of psychological stress. 2. In the absence of stress, the normal day/night sodium excretion ratio was reversed in the children of hypertensive parents. This was significantly less than day/night sodium excretion in children of normotensive parents. A similar finding was observed for day/night potassium excretion. 3. There was a significant negative correlation between systolic blood pressure and day/night sodium excretion in children of hypertensive parents but not in children of normotensive parents. 4. After the mental stress of a University examination day/night sodium reverted to normal in children of hypertensive parents.

Variability in 24-hour urine sodium excretion in children.

How many 24-hour urine sodium measurements are adequate for characterizing a child's salt intake? Can overnight urine specimens accurately replace 24-hour collections for salt assessment? A sample of 73 6th-8th grade children was taken from two parochial schools in Chicago to investigate systematically these questions. Seven consecutive 24-hour-urine specimens were collected from each child. The estimated ratio of intra- to inter-individual variances was 1.94 for 24-hour-urine sodium. Based on this value, eight 24-hour specimens are necessary to limit to 10% the diminution of the estimated correlation coefficient between 24-hour-urine sodium and blood pressure. Six measurements are required to reduce to 0.01 the probability of misclassifying a child in tertile 1 versus tertile 3. The overnight specimens show a moderate consistency with the 24-hour collections in detecting children with high or low salt intake. For example 92% and 85% of children in the fifth quintile and the third tertile respectively of the true mean overnight sodium have their true mean 24-hour Na in the upper half of the distribution. These results suggest that in a large scale epidemiologic study, overnight specimens may be reasonable alternatives when 24-hour-urine sodium is practically very difficult to collect.