24 hour urinary sodium excretion in essential hypertension

Hypertension is a common medical condition; its prevalence increases with age. It is one of the most important risk factors for cardiovascular disease, which is the leading cause of mortality. High salt intake is associated with high blood pressure. The incidence of hypertension is higher in salt-sensitive individuals. Evidence shows that reduced sodium intake lowers blood pressure and can prevent hypertension. Urinary sodium excretion was used as measure of sodium intake, which equals urinary excretion under normal circumstances. The relationship between salt intake and renal ability to excrete sodium has suggested being a major importance for the long-term blood pressure treatment especially in essential hypertension. In the present study there was increased 24 hour sodium excretion in essential hypertensives indicating a high intake of sodium, which may be the cause for hypertension. Patients with high sodium excretion, who are salt sensitive hypertensives will respond to diuretics, when compared to others. The long term reduction in salt intake may significantly reduce the prevalence of hypertension and thereby decrease the associated morbidity and mortality.

Association of 24-hour urinary sodium excretion and 25-hydroxy vitamin D level with albuminuria in patients with type 2 diabetes / 中华内分泌代谢杂志

Objective:Using 24-hour urinary sodium excretion (24h-UNa) as the surrogate measure of sodium intake, to evaluate the joint association of 24h-UNa and serum 25-hydroxy vitamin D (25-OHD) levels with the risk of albuminuria in patients with type 2 diabetes mellitus (T2DM).Methods:This retrospective study included 670 hospitalized T2DM cases in the Department of Endocrinology and Metabolic Diseases, the First Affiliated Hospital of Zhengzhou University from January 2018 to October 2021. Patients were divided into the albuminuria-positive group or negative-group according to the level of 24-hour urinary albumin excretion (24h-UAE); They were also divided into the high-sodium group or low-sodium group according to the level of 24h-UNa; Patients were divided into the low-VD group or high-VD group according to the level of 25-OHD. Combining 24h-UNa and 25-OHD, the patients were further divided into four groups: high-VD low-sodium group ( n=85), high-VD high-sodium group ( n=122), low-VD low-sodium group ( n=248), and low-VD high-sodium group ( n=215). The effect of 24h-UNa and 25-OHD association on albuminuria was analyzed by binary regression. Results:There were significant differences in 24h-UAE level among the four groups ( P<0.01), the level of 24h-UAE in the low-VD high-sodium group was significantly higher than that in low-VD low-sodium group, high-VD low-sodium group, and high-VD high-sodium group [39.00(13.00, 319.00)mg/24 h vs 22.00(10.00, 99.00)mg/24 h, 22.00(9.00, 72.50)mg/24 h, 22.45(9.69, 72.75)mg/24 h; P=0.047, P=0.019, P=0.030]. Correlation analysis showed a positive correlation between 24h-UNa and 24h-UAE in the low-VD group ( P=0.017), but not in the high-VD group ( P=0.411). Binary regression analyses showed that both 24h-UNa ( P=0.017) and 25-OHD( P=0.023) were independent risk factors for positive albuminuria in patients with T2DM. The risk of positive albuminuria in the low-VD high-sodium group was 1.789 times higher than that in the high-VD low-sodium group ( P=0.037). Conclusion:24h-UAE in T2DM patients was affected by the combination of 24h-UNa and 25-OHD. A low level of 25-OHD increased the risk of albuminuria in high sodium intake T2DM patients.

Development of objective indicators for quantitative analysis of sodium intake: the sodium to potassium ratio of second-void urine is correlated with 24-hour urinary sodium excretion

Feasibility and accuracy of Tanaka and SH2 methods used to estimate the 24-hour urinary sodium excretion of hypertension patients in Shanghai / 解放军医学杂志

Objective To validate and evaluate the feasibility and accuracy of Tanaka (T method) and SH2 (S method) used to estimate the 24-hour urinary sodium excretion of patients in Shanghai with hypertension. Methods A hundred and eighty hypertensive patients, hospitalized in the Internal Medicine Ward of Changhai Hospital affiliated to Navy Medical University from January 2017 to January 2018, were enrolled in present study. The specimens were collected of morning urine, afternoon urine, evening urine and the completed 24h urine, and the levels of sodium, potassium and creatinine in urine specimens were detected. The differences of estimation value calculated by T method and S method were compared, and the consistency of estimated value and actual urinary sodium excretion were compared by Bland-Altman plots respectively. Results There were 122 patients were enrolled in the final statistical analysis. The average urinary sodium excretion was 151.02mmol (about 8.83g salt). The average deviation values estimated by T method at 3 time points were 34.99, 22.72 and 48.76mmol, and estimated by S method were –6.83, –6.82, –6.31mmol. The intra-group correlation coefficient (ICC) was higher of T method in morning urine specimen and of S method in three time spots urine specimens. Bland-Altman plots showed that the higher the level of 24h urine sodium excretion, the greater the bias of S method with a linear trend. Conclusion Because of the varying degrees of limitation, both T and S methods are not suitable for estimating the individual 24h urinary sodium excretion. The two methods are suitable for estimating the average 24h urinary sodium level of population, while S method is more accurate than T method.

Association between Sodium Excretion and Obesity of Adults in Gwangju / 대한지역사회영양학회지

PURPOSE: The aim of this study was to analyze the association between sodium excretion and obesity for healthy adults in the Gwangju area. METHODS: The participants included 80 healthy adults aged 19 to 69 years in Gwangju. The dietary intake and sodium excretion were obtained using the 24-hour recall method and 24 hour urine collection. The participants were classified into two groups according to the amount of urinary sodium excretion: (≤ 141.75 mmol/dL, > 141.75 mmol/dL). RESULTS: After adjusting for sex, age, smoking history, and income, the high excretion of sodium group was significantly higher for weight, body mass index, body fat mass, percent body fat, visceral fat area (VFA), waist circumference, hip circumference, and WHR. The energy and nutrients intake were significant after adjusting for sex, age, smoking history, and income. The LSE group had a significantly higher fat intake and Na/K intake ratio. The HSE group had significantly higher fiber intake, and K intake. As the amount of urinary sodium excretion increased, the risk of obesity before correction was 3.57 (95% CI: 1.13–11.25) times greater, and the risk of obesity of T3 increased significantly by 3.33 times (95% CI: 1.05–10.59). After correcting for sex and age, the obesity risk of T2 increased significantly by 4.23 times (95% CI: 1.11–16.06), and after correcting for sex, age, smoking history, and income, the obesity risk of T2 increased significantly by 6.81 times (95% CI: 1.44–32.19) the risk of obesity. CONCLUSIONS: An association exists between sodium excretion and obesity in Korean adults. In this study, the high excretion of sodium group was obese and the risk of obesity was higher than the low excretion of sodium group.

Association between Sodium Excretion and Obesity of Adults in Gwangju / 대한지역사회영양학회지

PURPOSE: The aim of this study was to analyze the association between sodium excretion and obesity for healthy adults in the Gwangju area. METHODS: The participants included 80 healthy adults aged 19 to 69 years in Gwangju. The dietary intake and sodium excretion were obtained using the 24-hour recall method and 24 hour urine collection. The participants were classified into two groups according to the amount of urinary sodium excretion: (≤ 141.75 mmol/dL, > 141.75 mmol/dL). RESULTS: After adjusting for sex, age, smoking history, and income, the high excretion of sodium group was significantly higher for weight, body mass index, body fat mass, percent body fat, visceral fat area (VFA), waist circumference, hip circumference, and WHR. The energy and nutrients intake were significant after adjusting for sex, age, smoking history, and income. The LSE group had a significantly higher fat intake and Na/K intake ratio. The HSE group had significantly higher fiber intake, and K intake. As the amount of urinary sodium excretion increased, the risk of obesity before correction was 3.57 (95% CI: 1.13–11.25) times greater, and the risk of obesity of T3 increased significantly by 3.33 times (95% CI: 1.05–10.59). After correcting for sex and age, the obesity risk of T2 increased significantly by 4.23 times (95% CI: 1.11–16.06), and after correcting for sex, age, smoking history, and income, the obesity risk of T2 increased significantly by 6.81 times (95% CI: 1.44–32.19) the risk of obesity. CONCLUSIONS: An association exists between sodium excretion and obesity in Korean adults. In this study, the high excretion of sodium group was obese and the risk of obesity was higher than the low excretion of sodium group.

Estimating the urinary sodium excretion in patients with chronic kidney disease is not useful in monitoring the effects of a low-salt diet

BACKGROUND: Several epidemiologic studies have suggested that the urine sodium excretion (USE) can be estimated in lieu of performing 24-hour urine collection. However, this method has not been verified in patients with chronic kidney disease (CKD) or in an interventional study. The purpose of this study was to evaluate the usefulness of estimating USE in a prospective low-salt diet education cohort (ESPECIAL). METHODS: A new formula was developed on the basis of morning fasting urine samples from 228 CKD patients in the ESPECIAL cohort. This formula was compared to the previous four formulas in the prediction of 24-hour USE after treatment with olmesartan and low-salt diet education. RESULTS: Most previously reported formulas had low predictability of the measured USE based on the ESPECIAL cohort. Only the Tanaka formula showed a small but significant bias (9.8 mEq/day, P < 0.05) with a low correlation (r = 0.34). In contrast, a new formula showed improved bias (−0.1 mEq/day) and correlation (r = 0.569) at baseline. This formula demonstrated no significant bias (−1.2 mEq/day) with the same correlation (r = 0.571) after 8 weeks of treatment with olmesartan. Intensive low-salt diet education elicited a significant decrease in the measured USE. However, none of the formulas predicted this change in the measured urine sodium after diet adjustment. CONCLUSION: We developed a more reliable formula for estimating the USE in CKD patients. Although estimating USE is applicable in an interventional study, it may be unsuitable for estimating the change of individual sodium intake in a low-salt intervention study.

The Association of Knowledge, Attitude and Practice with 24 Hours Urinary Sodium Excretion among Malay Healthcare Staff in Malaysia

The most effective and affordable public health strategy to prevent hypertension, stroke and renal disease is by reducing daily salt consumption. Therefore, this study aims to determine the association of knowledge, attitude and practice on salt diet intake and to identify foods contributing to high sodium intake. Secondary data analysis was performed on MySalt 2016 data. It was conducted from November 2015 until January 2016 which involving Ministry of Health Staff worked at 16 study sites in Malaysia. Salt intake was measured using 24 hours urinary sodium excretion. Food frequency questionnaire was used to determine the sodium sources. Knowledge, attitude and practice of salt intake were assessed using a validated questionnaire adapted from WHO. Demographic data and anthropometric measures also were collected. Sodium levels of more than 2400mg/day was categorised as high sodium intake. Data were analysed using SPSS software version 21. The mean sodium intake estimated by 24 hours urinary sodium excretion was 2853.23 + 1275.8 mg/day. Food groups namely rice/noodles (33.8%), sauces/seasoning (20.6%), meat and poultry (12.6%) and fish/seafoods (9.3%) were the major contributors of dietary sodium. In multiple logistic regression analysis, being a male (aOR=2.83, 95% CI 2.02 – 3.96) and obese (aOR=6.78, 95% CI 1.98 – 23.18) were significantly associated with high urinary sodium excretions. In addition, those who were unsure that high salt intake can cause hypertension (aOR=1.24, 95% CI 0.65 – 2.36), those who think that they consumed too much salt (aOR=2.10, 95% CI 1.13 – 3.87) and those who only use salt rather than other spices for cooking (aOR=2.07, 95% CI 1.29 – 3.30) were significantly associated with high urinary sodium excretion. This study showed that the main sources of sodium among Malay healthcare staff is cooked food. Poor knowledge and practice towards reducing salt consumption among them contributes to the high sodium consumption. The practice of healthy eating among them together with continuous awareness campaign is essential in order to educate them to minimize sodium consumption and to practice healthy eating.​

Associations between 24-hour Urine Sodium Excretion Level and Obesity-related Metabolic Risk Factors / 대한지역사회영양학회지

OBJECTIVES: Excess sodium intake has been linked to obesity and obesity-related indices. However, the scientific evidence for this association is inadequate. The purpose of this study was to investigate the association between urinary sodium excretion and obesity-related indices among Korean adults. METHODS: A convenience sample of 120 subjects (60 obese and 60 non-obese subjects) were recruited applying frequency matching for sex and age between two groups. Sodium intake level was assessed through 24-hour urine collection. Obesity-related metabolic risk factors, including fasting blood lipid indices, subcutaneous and visceral fat through computed tomography (CT), insulin resistance indices, blood pressure and liver enzymes were measured in all subjects. These obesity-related metabolic risk factors were compared between obese and non-obese group according to sodium excretion levels (180 mEq/day). RESULTS: After adjusting for age, gender, health behaviors (smoking, exercise, drinking), and energy intake, several obesity-related metabolic risk factors, including abdominal circumference, body fat percentage, subcutaneous and visceral fat, triglyceride, and systolic blood pressure were found to be significantly deteriorated as the sodium excretion level increases. In addition, multivariate adjusted-odds ratios of abdominal obesity, high blood triglyceride, and high blood pressure were found significantly higher in the highest sodium excretion group compared to the lowest group. The mean number of metabolic syndrome risk factors was also significantly greater in the highest sodium excretion group than in the lowest group. CONCLUSIONS: The current study findings suggested that high sodium intake can affect obesity and metabolic syndrome risk negatively, implying the necessity of future research on low-sodium diet intervention in relation to obesity and related health problems.

Ingestión de sodio en pacientes litiásicos y su relación con variables demográficas y nutricionales / Sodium intake in lithiasic patients and its relationship to demographic and nutritional variables

Introducción: la medición de la excreción urinaria de sodio es importante en pacientes con litiasis urinaria, pues su excreción elevada predispone a hipercalciuria, el trastorno metabólico urinario más frecuente. Objetivo: determinar la ingestión (igual a excreción) de sodio e identificar su posible relación con variables demográficas y nutricionales, en pacientes con litiasis urinaria. Métodos: se desarrolló un estudio analítico, transversal, de los pacientes con litiasis urinaria que se hicieron estudio metabólico renal en el Instituto de Nefrología, entre enero 2011 y diciembre 2012. Se excluyeron los pacientes con factores que modifican la excreción de sodio. Las determinaciones de creatinina fueron realizadas por el método cinético de Jaffé, con espectrofotómetro Jenway®; las mediciones del sodio urinario, con analizador electrolítico marca Roche®. La información fue procesada de forma automatizada (SPSS versión 15.0). En cada categoría de las variables fueron calculadas media y desviación estándar de la excreción de sodio (mEq/d). Las comparaciones de los promedios se realizaron mediante la prueba t o mediante ANOVA. Resultados: de 1 985 pacientes estudiados, 1 363 fueron del sexo masculino (68,7 por ciento) y 622, del femenino (31,3 por ciento). La excreción urinaria media de sodio fue 235,29 mEq/d, globalmente, y resultó mayor en los hombres (252,69 mEq/d), al ser comparada con la de las mujeres (197,14 mEq/d) (p= 0,00). También se encontraron diferencias al comparar la excreción de sodio entre las categorías de valoración nutricional (p= 0,00) y de excreción de creatinina (p= 0,0). Conclusiones: la excreción urinaria de sodio es elevada en pacientes urolitiásicos, mayor en los hombres y en los sujetos con sobrepeso y obesidad...

Introduction: measurement of urinary sodium excretion is important in patients with urolithiasis, for a high level of excretion leads to hypercalciuria, the most common urinary metabolic disorder. Objective: to determine sodium intake (equal to excretion) and identify its possible relationship to demographic and nutritional variables in patients with urinary lithiasis. Methods: an analytical cross-sectional study was conducted in patientes with urinary lithiasis undergoing metabolic renal study at the Institute of Nephrology from January 2011 to December 2012. Patients with factors modifying sodium excretion were excluded. Creatinine determinations were made with Jaffé's kinetic method using a Jenway™ spectrophotometer. Urinary sodium was measured with a Roche™ electrolytic analyzer. Data was processed with the statistical software SPSS version 15.0. Variables for each category were estimated as mean and standard deviation of sodium excretion (mEq/d). Comparisons of averages were made with the t test or ANOVA. Results: of the 1 985 patients studied, 1 363 were male (68.7 percent) and 622 were female (31.3 percent). Global mean sodium urinary excretion was 235.29 mEq/d, greater in men (252.69 mEq/d) than in women (197.14 mEq/d) (p= 0.00). Differences were also found when sodium excretion was compared by nutritional assessment (p= 0.00) and creatinine excretion (p= 0.0). Conclusions: urinary sodium excretion is high in patients with urolithiasis. Values are higher in men, and in overweight and obese individuals...

Adiposidad abdominal, insulino-resistencia, hipertensión y sodio urinarioen adolescentes obesos / Abdominal adiposity, insulin resistance, hypertension and urinary sodium in obese adolescents / Adiposidade abdominal, insulino-resistência, hipertensão e sódio urinário em adolescentes obesos

El objetivo de este estudio fue evaluar la relación entre adiposidad abdominal con insulino-resistencia, hipertensión arterial y excreción urinaria de sodio en adolescentes obesos. Se realizó un estudio transversal descriptivo que incluyó 107 adolescentes obesos, entre 10 y 14 años, sin restricción dietaria, provenientes del Hospital de Pediatría-Posadas, Misiones, durante los años 2011-2012. Se definió obesidad abdominal según: perímetro de cintura ≥p90, hipertensión arterial: presión arterial sistólica y/o diastólica ≥p95 y prehipertensión ≥p90 y

The aim of this study was to assess abdominal adiposity relationship with insulin resistance, high blood pressure and urinary sodium excretion in an obese adolescent population. A descriptive cross sectional study that included 107 obese teenagers from 10 to 14 years of age without any dietary restriction was performed during 2011 and 2012 at the Pediatric Hospital, in Posadas, Misiones. Abdominal obesity was defined as: waist perimeter ≥p90, hypertension: systolic and/or diastolic pressure ≥p95 and prehypertension ≥p90 and

O objetivo deste estudo foi avaliar a relação de adiposidade abdominal com insulino-resistência, hipertensão arterial e excreção urinária de sódio em adolescentes obesos. Foi realizado um estudo transversal descritivo que incluiu 107 adolescentes obesos, entre 10 e 14 anos, sem restrição na dieta, provenientes do Hospital de Pediatría Posadas, Misiones, durante os anos 2011-2012. Definiu-se obesidade abdominal conforme o perímetro de cintura ≥p90, hipertensão arterial: pressão arterial sistólica e/ou diastólica ≥p95 e pré-hipertensão ≥p90 e

Postmenopausal Hypertension and Sodium Sensitivity

It has been well established that women generally have lower incidence rates of hypertension than men at similar ages and these differences may vary with age. It also has been observed in many studies that after menopause, blood pressure (BP) increases in women to levels even higher than in men. The lack of estrogens may not be suggested as the only component involved in the development of postmenopausal hypertension. Thus, in this mini-review, the possible mechanisms by which sex hormones may influence the BP are discussed. This review also examines the renal regulatory mechanisms for gender differences in BP and explores the effects of salt intake on BP (salt-sensitivity) in pre and post-menopausal women. Estrogen has been shown to stimulate nitric oxide (NO) production, thus female sex hormones have a beneficial effect on BP control. Evidences that angiotensin type 2 receptor (AT2R) is up-regulated by estrogen support the favorable effects on BPs in women than men. The kidney plays an integral role in the regulation of arterial pressure through the mechanism of pressure-natriuresis, which has been shown to be modulated by the RAS. The prevalence of salt-sensitivity increases with age and low-salt diets has shown to help reduce systolic BP (SBP) and diastolic BP. While oral hormone replacement therapy has yielded only a neutral or minimal effect on the elevation of SBP, both the transdermal route replacement and a novel progestin with anti-aldosterone activity (drospirenone) has also shown to reduce SBP.

High Dietary Sodium Intake Assessed by 24-hour Urine Specimen Increase Urinary Calcium Excretion and Bone Resorption Marker

BACKGROUND: The average dietary sodium intake of Koreans is 2.6 times higher than the World Health Organization's recommended amount. The effect of a diet high in sodium on the skeletal system, especially osteoporosis, has not previously been examined in Korean postmenopausal women with low bone mass. We assessed the daily sodium intake, and determined the impact of sodium intake on urinary calcium excretion and bone resorption marker. METHODS: A retrospective review of medical records was performed for 86 postmenopausal subjects who were initially diagnosed with osteopenia or osteoporosis at the health promotion center. They were subsequently referred to the Division of Endocrinology and Metabolism between 2010 and 2013. All subjects completed a modified food frequency questionnaire. Twenty-four hour urine collection for sodium, calcium and creatinine excretion, and serum C-terminal telopeptides of type I collagen (CTX-I) were also obtained. RESULTS: The average amount of daily sodium and calcium intake were 3,466 mg and 813 mg, respectively. Average dietary sodium intake and 24-hour urinary sodium excretion showed significant positive linear correlation (r=0.29, P=0.006). There was also a significant positive linear correlation between 24-hour urine sodium and calcium excretion (r=0.42, P<0.001); CTX-I and 24-hour urinary calcium excretion (r=0.29, P=0.007). CONCLUSIONS: Excessive sodium intake assessed by 24-hour urine specimen is associated with high calcium excretion in urine. High calcium excretion is also related to increasing bone resorption marker.

Analysis of presumed sodium intake of office workers using 24-hour urine analysis and correlation matrix between variables

The purpose of this study was to investigate the sodium intake of office workers using 24-hour urine analysis and to analyze the correlation matrix between variables. The sodium intake of the subjects (n = 137), based on a 24-hr sodium excretion period, was male (n = 56) 6072.4 mg and female (n = 81) 5,168.2 mg. Urinary sodium excretion showed significant positive correlation with BMI, frequency of eating out, expenditure of eating out, salty taste assessment and high-salt dietary behavior. Analysis of urinary sodium excretion showed significant positive correlation with intake frequencies of cabbage kimchi, broiled fish, feast noodle and rice with leaf wraps. Based on the results of multiple regression, urinary sodium excretion was found to be related to intake frequencies of cabbage kimchi, broiled fish, rice with leaf wraps and high score of high-salt dietary behavior.

Correlation between salt consumption and certain behavioral factors in the population of the eastern and Khangai regions of Mongolia / Монголын Анагаах Ухаан

IntroductionIn Mongolia, cardiovascular diseases (CVDs) and stroke have consistently been the number one cause of population mortality since 1990s. Hypertension is an independent risk factor for CVDs and stroke. There is a conclusive evidence that high salt intake is the strongest dietary factor for hypertension. However, in Mongolia, evidence on actual salt intake of the population, its potential sources and relations to high blood pressure has been in lack so far.GoalThe survey was aimed to determine actual daily salt intake and related behavior patterns in the population residing in Eastern and Khangai regions and in the city and to identify the directions of further activities to decrease the amount of salt consumed per day by the target population.Materials and MethodsThe survey recruited a total of 475 adults from Khentii, Bulgan aimags and Bayanzurkh district of Ulaanbaatar. Questionnaires, physical measurements and laboratory analyses were applied to collect and process the data on population demographics, behavior patterns and salt related KAP, blood pressure and sodium and potassium values in 24 hour urine samples to estimate daily salt intake. A survey database was developed using EPI INFO and the data was entered in twice. SPSS 18 software was used for the data analysis, mean and standard deviations were estimated using t and F statistics on continuous variables with normal distribution, and chi square test was applied to differences in proportions.ResultsMean age of the survey population was 44.5 years; the survey population was not differing in their age, gender and region. Average daily consumption of salt was 9.5 grams in the survey population; it was not differing in terms of region. Men consumed on average 10.1 grams of salt which is twice much higher than the WHO recommended amount. Salt consumption was higher among those aged 45-54 years and rural persons, particularly men. For men and people aged 45-54 years old, the salt consumption was directly related to their salt tea drinking habit (r= 0.14; p=0.04). Those who drink alcoholic drinks frequently have higher body mass index and/or less educational attainment were more likely to drink tea with salt. In the Eastern Region, regardless of a habit of drinking tea without salt, the high salt consumption seems to be caused by insufficient knowledge of salt containing meals and food products (r=.27; p=0.001), lack of awareness of health impacts of salt, as well as lack of attitude towards their control of daily salt intake (r= ; p= ). In the Khangai Region and the urban city, salt added to meals and food preparation (Partial r =.22; p=0.05), salt containing food products and salt tea are the main factors of high salt consumption. The survey population in these areas lacks attitude and practice to decrease and control their daily salt intake.ConclusionSalt consumption is generally high among the adults of the Eastern and Khangai Regions and in UB city; males and rural people are lacking in knowledge and attitude related with salt content of food, food choice and with the potential health impacts of excessive sodium intake.

Correlation between sodium and potassium excretion in 24- and 12-h urine samples

Low-sodium and high-potassium diets have been recommended as an adjunct to prevention and treatment of hypertension. Analysis of these nutrients in 24-h urine has been considered the reference method to estimate daily intake of these minerals. However, 24-h urine collection is difficult in epidemiological studies, since urine must be collected and stored in job environments. Therefore, strategies for shorter durations of urine collection at home have been proposed. We have previously reported that collecting urine during a 12-h period (overnight) is more feasible and that creatinine clearance correlated strongly with that detected in 24-h samples. In the present study, we collected urine for 24 h divided into two 12-h periods (from 7:00 am to 7:00 pm and from 7:00 pm to 7:00 am next day). A sample of 109 apparently healthy volunteers aged 30 to 74 years of both genders working in a University institution was investigated. Subjects with previous myocardial infarction, stroke, renal insufficiency, and pregnant women were not included. Significant (P < 0.001) Spearman correlation coefficients (r s) were found between the total amount of sodium and potassium excreted in the urine collected at night and in the 24-h period (r s = 0.76 and 0.74, respectively). Additionally, the 12-h sodium and potassium excretions (means ± SD, 95% confidence interval) corresponded to 47.3 ± 11.2%, 95%CI = 45.3-49.3, and 39.3 ± 4.6%, 95%CI = 37.3-41.3, respectively, of the 24-h excretion of these ions. Therefore, these findings support the assumption that 12-h urine collected at night can be used as a reliable tool to estimate 24-h intake/excretion of sodium and potassium.

Niveles séricos de leptina y su relación con la excreción de sodio en niños y adolescentes obesos / Relationship between serum leptin levels and sodium excretion in a local population of obese children and adolescents

La obesidad se asocia con niveles elevados de leptina y la mayoría de los individuos obesos presentan resistencia "selectiva" a su acción metabólica sin disminución del apetito ni aumento en el gasto energético, con preservación y estimulación de la activación del sistema simpático a nivel central y de las acciones periféricas cardiovasculares y renales. Estos mecanismos podrían modificar la regulación del metabolismo del sodio a nivel renal. Objetivo: identificar el comportamiento de los niveles séricos de leptina en asociación a la excreción urinaria de sodio en una población de niños y adolescentes obesos. Material y métodos: se estudiaron 190 niños y adolescentes entre 5 y 15 años: 125 con índice de masa corporal (IMC) percentilo = 95 constituyeron el grupo de obesos (OB) y 65 con IMC percentilo 5 - < 85 el grupo control (C). Las concentraciones de sodio sérico (Nas) y urinario (Nao) se midieron por electrodo ión selectivo; los niveles séricos de leptina por método radioinmunométrico. Resultados: se encontraron diferencias significativamente menores en los valores de sodio urinario (mEq/ kg/día) de la población obesa respecto a los controles, para ambos sexos en los distintos grupos etarios y se observó que los obesos presentan mayores valores de leptina/IMC (ng/ml/IMC) para menores concentraciones de sodio urinario en los diversos grupos/subgrupos: nenas OB 5 a 9 años: Nao 2,69 ± 0,19, leptina/IMC 0,63 ± 0,06; nenas OB 10 a 15 años: Nao 2,20 ± 0,17,leptina/IMC 1,11± 0,12; nenes OB 5 a 9 años: Nao 2,07± 0,16, leptina/IMC 0,80 ± 0,15; nenes OB 10 a 15 años: Nao 2,57 ± 0,23, leptina/IMC 0,65 ± 0,09. Nuestros resultados sugieren que los niveles séricos de leptina elevados, típicos de estados como la obesidad, podrían contribuir a las alteraciones en el metabolismo del sodio, dada la disminución de la excreción urinaria de dicho ión.

Obesity is associated with elevated levels of leptin and most obese individuals are "selectively" resistant to its metabolic action, without appetite loss or increased energy expenditure, with preservation and stimulation of the activation of the sympathetic system at both the central and peripheral cardiovascular and renal levels. These mechanisms could modify the regulation of sodium metabolism in the kidney. Objective: To determine whether there is any correlation among between serum leptin levels and urinary sodium excretion in a population of obese children and adolescents an obese, children and adolescents. Material and methods: 190 children and adolescents between 5 and 15 years of age were studied: 125 with body mass index (BMI) = 95 percentile constituted the obese group (OB) and 65 with BMI percentile 5 - < 85 the control group (C). Concentrations of serum sodium (Na) and urinary sodium (Nao) were measured with ion selective electrode; serum leptin levels were measured by the immunoradiometric method. Results: Differences between groups were significantly lower for urinary sodium values (mEq/kg/day) in obese subjects compared with controls for both sexes and in different age groups. The obese population has higher leptin/BMI (ng/ml/IMC) and lower concentrations of urinary sodium in the different groups/subgroups: OB girls 5 to 9 years of age Nao 2.69 ± 0.19, leptin/BMI 0.63 ± 0.06; OB girls 10 to 15 years Nao 2.20 ± 0.17, leptin/BMI 1.11± 0.12; OB boys 5 to 9 years Nao 2.07± 0.16, leptin/BMI 0.80 ± 0.15; OB boys 10 to 15 years Nao 2.57 ± 0.23, leptin/BMI 0.65 ± 0.09. Our study suggest that elevated serum leptin levels, typical of conditions such as obesity, may contribute to alterations in sodium metabolism, due to decreased urinary excretion of this ion.

A Study on the Calcium and Sodium Intakes and Urinary Calcium Excretion of Adults in Busan / 대한지역사회영양학회지

The purpose of this study was to assess calcium and sodium intakes and urinary excretion of adults in Busan and to evaluate the relationship between urinary calcium excretion (UCa) and the status of anthropometric, blood pressure, urine analysis, and nutrient intake of subjects. Nutrient intake by 24 hr recall, 24 hr urinary calcium and sodium excretion (UNa) were measured with 87 adults aged 20-59 yrs (42 men and 45 women). The mean calcium intake was 88.0% for men and 103.0% for women of Recommended Intake. The mean sodium intake was 283.4% for men and 250.5% for women of Adequate Intake (AI). The mean 24hr UCa was 127.4 mg in men and 107.3 mg in women. The mean 24 hr UNa was 3650.6mg in men and 3276.4mg in women. The intake and urinary excretion of calcium and sodium were not significantly different by gender. UCa showed significantly positive correlations with sodium intake and UNa in men (p < 0.001, p < 0.05) and women (p < 0.001, p < 0.001) and with age, systolic blood pressure (SBP) and sodium density in women (p < 0.05, p < 0.05, p < 0.01). The UCa/creatinine showed significantly positive correlations with age, sodium intake, sodium density, and UNa in women (p < 0.05, p < 0.01, p < 0.01, p < 0.01). When UCa was stratified into quartile (Q1-Q4), age, SBP, UCa, UNa, sodium intake, and AI percentage of sodium (p < 0.01, p < 0.05, p < 0.001, p < 0.001, p < 0.001, p < 0.001) were significantly higher in Q4. The mean intake and AI percentage of sodium in Q4 were 4768.8mg and 329.0. Based on the results, UCa was related to age, SBP, UNa, and sodium intake. Therefore, nutritional education of decreasing sodium intake for decreasing UCa is needed.

Yanomamos: ingestión de sal e hipertensión arterial / Yanomamos: salt intake and arterial hypertension

La nación yanomama es un grupo indigena aislado y autosuficiente que reside en la selva lluviosa al sur de Venezuela y norte de Brasil que ha logrado vivir en armonia con su ambiente y que ha mostrado ancestral respecto a la naturaleza sin producir basura ni contaminación. Deparam la sal que necesitan de un àrbol de la misma región llamado Tavarí. El Estudio Intersalt es una investigación observacional que ha demostrado una asociación entre la presión arterial y el consumo de sal de la dieta a través de la medición de su excreción urinaria. Los hallazgos encontrados en este grupo poblacional fueron extraordinarios: Niveles de presión arterial muy bajos que no se incrementaron con la edad, niveles de colesterol muy reducidos, ausencia de alcoholismo u obesidad. Constituyen un experimento de la naturaleza digno de seguir; desafortunadamente el mundo occidental ha tenido un impacto negativo en sus vidas y cultura

The nation yanomami is an isolated and self-sufficient indigenous group who reside in the rainy forest to the south of Venezuela and north of Brazil that has managed to live in harmony with its atmosphere and that has shown ancestral respect to the nature without producing any sweepings or contamination. They obtain the salt that needs from a local tree of called Tavarí. The Intersalt Study is an observational investigation that has demostrated an association between the arterial pressure and the consumption of salt of the diet through the measurement of its urinary excretion. The findings found in this population group were extraordinary: very low levels of pressure arterial that are not increased with the age, cholesterol levels very reduced, absence of alcoholism or obesity, very low sodium excretion. They constitute an experiment of the nature worthy to follow; unfortunately western world had much of a negative impact on their lives or culture

Effect of a 6-month Low Sodium Diet on the Salt Taste Perception and Pleasantness, Blood Pressure and the Urinary Sodium Excretion in Female College Students

The study aim was to examine the effect of sensory responses of subjects after 6-month dietary sodium reduction with the aid of nutritional education. Fourteen female college students voluntarily restricted their sodium intake for 6 months, during which time they received nutritional education on the low sodium diet. As a control group, 10 students, whose anthropometric measurement, sodium intake behavior, and blood pressure were not different from those of the experimental group, were maintained on a normal diet. For the sensory responses of subjects, the salt taste perception and pleasantness for graded (0.15-1.3%) NaCl solutions were measured by a 9-point hedonic scale. The optimum sodium concentration, urinary sodium excretion, and blood pressure were measured. All the measurements were done at the beginning and end of the experiment. The sensory evaluation revealed an absence of any difference between the two groups in salt taste perception and pleasantness responses at the beginning. After 6-month adaptation, the experimental group subjects showed higher responses to low NaCl solution (0.15, 0.3, 0.5%) in salt taste perception and pleasantness evaluation while the control group subjects exhibited the opposite response. The optimum sodium concentration was reduced from 105.6 mmol to 80.7 mmol (p = 0.015) and the urinary sodium excretion was also reduced from 1,398 mg to 906 mg (p = 0.041) only in the experimental group. Systolic blood pressure was significantly reduced in the experimental group, although there was no correlation between the urinary sodium excretion and blood pressure. The optimum sodium concentration was negatively correlated with the urinary sodium excretion (r = 0.418, p = 0.053), indicating that adaptation to low sodium diet can reduce sodium intake. Further study on the individual responses of subjects on a low sodium diet by periodical evaluation may provide useful data for setting the duration needed to stabilize a lowered appetite for sodium.