24-hour Urine Samples Research Articles

Accuracy of the methods used to estimate glomerular filtration rate compared to 24-hour urinary creatinine clearance in patients with chronic spinal cord injury

Objective: To compare the accuracy of glomerular filtration rate (GFR) estimation by 24-hour urinary creatinine clearance with GFR estimation by the Modification of Diet in Renal Disease (MDRD) equation, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, the Mayo Clinic Quadratic equation (MCQE), and the modified Cockcroft–Gault formula in patients with spinal cord injury (SCI). Design: Cross-sectional study. Participants: Fifty-nine consecutive subjects, who were admitted to our hospital SCI rehabilitation and no additional acute medical disorders, were enrolled in this study. A 24-hour urine sample was collected for the determination of 24-hour urinary creatinine clearance, which was assumed as the standard technique for estimation of the GFR. The accuracy of several estimation formulas includes the 4-variable MDRD equation, the 6-variable MDRD equation, the Cockcroft and Gault equation, the CKD-EPI equation, and the MCQE. Results: GFRs calculated by the Cockcroft–Gault equation and 4-variable MDRD were significantly different from the 24-hour urinary creatinine clearance, whereas there were no significant differences in GFRs calculated by CKD-EPI (P = 1.000), Mayo Clinic Quadratic formula (P = 0.794), and 6-variable MDRD equations (P = 0.435) and 24-hour urinary creatinine clearance. Both the 6-variable MDRD equation and CKD-EPI were accurate within ±20 of the reference methods in 52.54% of the subjects. Conclusions: Among the methods used for estimation of the GFR including the 4- and 6-variable MDRD, the CKD-EPI, the modified Cockcroft–Gault equation, and the MCQE, the 6-variable MDRD equation and the CKD-EPI demonstrated best performance to estimate the GFR. However, none of the formulas were sufficient to estimate the GFR in SCI patients accurately.

Study of rs10177833 polymorphism in SLC4A5 gene and salt sensitivity in Bulgarian population

Abstract High sodium intake is associated with increased blood pressure and and increased risk of cardiovascular disease (CVD). Among the countries of the European Union, Bulgaria ranks first in mortality from CVD. Genetically determined salt sensitivity is present in 50% of the hypertensive and 26% of the normotensive population, posing a major public health problem. The present study was conducted within the National Program for Prevention of Chronic Non-Communicable Diseases 2014 - 2020 to assess the sodium intake of the population in Bulgaria. 36 normotensive participants are included in the study. DNA from each volunteers was isolated and genotyped for rs10177833 (A>C) in SLC4A5 gene by TaqMan SNP genotyping assay. To determine the 24-hour urinary excretion of sodium in the subjects, a random sample was taken from each participant. Sodium concentration was determined by atomic absorption spectrometry. A WHO protocol has been used to recalculate sodium excretion (Protocol for Sodium Determination in 24-hour Urine Samples). Eighteen of total of 35 participants had wild AA genotype (51.43%), thirteen were heterozygotes (37.14%) and four were carriers of two polymorphic C alleles (11.43%). The frequency of A allele of rs10177833 (A>C) in SLC4A5 gene was 70%, whereas polymorphic C allele was only 30%. The correlation analysis showed negative statistical significant relationship between rs10177833 in SLC4A5 gene and sodium concentration (in milligrams) in 24 - hours urine (r = -0.365, p = 0.031). Also the holders of CC genotype had significant lower values of Na compared to these with wild AA genotype (p = 0.01) and compared to heterozygotes (p = 0.019). In conclusion, we found a clear relationship between the polymorphic variant rs10177833 in SLC4A5 gene and the concentration of sodium in urine in Bulgarian normotensives. The tendency of association was found between the studied polymorphic variant and blood pressure values, which should be studied in a large number of participants Key messages Increasing the population's awareness of health risks with increased salt consumption. Regular monitoring of salt consumption.

Body fluids from the rat exposed to chlorpyrifos induce cytotoxicity against the corresponding tissue\u2212derived cells in vitro

BackgroundThis study aims to establish an in vitro monitoring approach to evaluate the pesticide exposures. We studied the in vitro cytotoxicity of three different body fluids of rats to the respective corresponding tissue-derived cells.MethodsWistar rats were orally administrated daily with three different doses of chlorpyrifos (1.30, 3.26, and 8.15 mg/kg body weight/day, which is equal to the doses of 1/125, 1/50, and 1/20 LD50, respectively) for consecutive 90 days. Blood samples as well as 24-hour urine and fecal samples were collected and processed. Then, urine, serum, and feces samples were used to treat the correspondent cell lines, i.e., T24 bladder cancer cells, Jurkat lymphocytes, and HT-29 colon cancer cells respectively, which derived from the correspondent tissues that could interact with the respective corresponding body fluids in organism. Cell viability was determined by using MTT or trypan blue staining.ResultsThe results showed that urine, serum, and feces extract of the rats exposed to chlorpyrifos displayed concentration- and time-dependent cytotoxicity to the cell lines. Furthermore, we found that the cytotoxicity of body fluids from the exposed animals was mainly due to the presence of 3, 4, 5-trichloropyrindinol, the major toxic metabolite of chlorpyrifos.ConclusionsThese findings indicated that urine, serum, and feces extraction, especially urine, combining with the corresponding tissue-derived cell lines as the in vitro cell models could be used to evaluate the animal exposure to pesticides even at the low dose with no apparent toxicological signs in the animals. Thus, this in vitro approach could be served as complementary methodology to the existing toolbox of biological monitoring of long-term and low-dose exposure to environmental pesticide residues in practice.

Rationale and validation of predicting high sodium intake by spot urinary chloride in patients with chronic kidney disease.

To analyze the rationale and evaluate the validity of spot urinary chloride or derived formulas to predict high sodium intake in patients with chronic kidney disease (CKD). We collected consecutive CKD patients at stages 1-4 who were admitted to our Nephrology department in a single center from January 01, 2014, to December 31, 2017, and tested spot and 24-hour urinary analysis on the same day. The feasibility of urinary chloride to predict urinary sodium was firstly analyzed by calculating their correlations. The validity of predicting excessive sodium intake by spot urinary sodium and chloride, two derived formulas based on spot urinary sodium or chloride, and our previous "CKDSALT" equation were accessed. We finally conducted Receiver operating characteristic (ROC) curves to compare their performance in detecting high sodium intake. All 5204 patients were eventually analyzed. In the derivation cohort (n=2447), a strong positive linear correlation existed between urinary sodium and chloride in both spot urine (R2=0.804) and 24-hour urine samples (R2=0.905), and two predictive equations based on spot urinary sodium or chloride were derived. In the validation cohort (n=2757), spot urinary sodium and chloride only showed "fair" performance. However, both urinary sodium and chloride equations had a "good" performance in ICC, Pearson's correlation, Bland-Altman plots, and ROC curves, while and CKDSALT equation showed the best performance. Spot urinary chloride is a feasible method to predict and monitor high sodium intake in CKD patients, while a novel derived formula could elevate its diagnostic accuracy.

Association of Urinary Sodium Excretion and Left Ventricular Hypertrophy in People With Type 2 Diabetes Mellitus: A Cross-Sectional Study

BackgroundIt has been well documented that left ventricular hypertrophy (LVH) is highly associated with the incidence of cardiovascular disease (CVD). Evidence indicated that high sodium intake was closely related with LVH in general population. However, information is not available regarding the association between urinary sodium excretion and LVH in patients with type 2 diabetes mellitus (T2DM). This study aimed to explore the association between urinary sodium excretion and LVH in patients with T2DM.MethodsThis cross-sectional analysis included baseline data from 1,556 individuals with T2DM enrolled in the NanFang Prospective Diabetes Study (NFPDS). Urinary sodium excretion levels were measured from 24-hour urine samples of inpatients and morning fasting urine samples of outpatients. Left ventricular dimensions were assessed by echocardiography. The associations between urinary sodium excretion and the risks of cardiovascular events, LVH and left ventricular mass index (LVMI) were examined using linear regression analysis, logistic regression and restricted cubic splines (RCS).ResultsUrinary sodium excretion levels were positively associated with cardiometabolic risk factors, including systolic blood pressure, body mass index, waist circumference and LVMI (All P<0.001). Odds ratios of the highest quartile of urinary sodium excretion compared with the lowest quartile were 1.80 (95% CI, 1.28-2.54; P=0.001) for LVH and 1.77 (95% CI, 1.06-2.94; P=0.028) for CVD, after adjusted for demographics, lifestyle risk factors and cardiovascular risk factors. Multivariable-adjusted RCS analysis of the association between urinary sodium excretion and LVMI showed a significant association (P=0.001) and lacked evidence of a nonlinear association (P=0.406).ConclusionThis study indicated that high urinary sodium excretion was independently associated with increased risk of LVH and CVD in patients with T2DM, suggesting that control of sodium intake may be valuable for the prevention of diabetic cardiovascular complications.

Development of Canine Chronic Kidney Disease Model: A Pilot Study

Chronic kidney disease (CKD) is a worldwide health problem with a poor prognosis. The exploration of possible medical intervention requires the presence of a suitable animal model. This work aims to induce a model of canine CKD with persistent uremia. Three dogs were used to develop canine CKD models with different techniques based on the remnant kidney model. Model (1) was subjected to excision of one renal pole of the right kidney. Model (2) was subjected to the excision of two renal poles of the right kidney. Model (3) underwent ligation of two renal arterial branches of the right kidney. A contralateral nephrectomy was performed in the three models after two weeks from the first operation. Blood and 24-hour urine samples were collected weekly to determine renal function parameters. Histopathology, Immunohistochemistry of α-SMA expression, and quantitative real-time PCR for Kim-1 &amp; NGAL gene expression were performed on kidney tissues. According to the IRIS staging system in dogs, model (1) represented stage one of CKD with less expression of genes and α-SMA in the interstitial tissue. Model (2) represented stage three of CKD with moderate expression of genes and α-SMA and moderate glomerulointerstitial nephritis. Model (3) suffered from severe uremia. It showed the highest expression of genes and α-SMA with severe glomerulointerstitial nephritis and infarction. Therefore, model (2) was considered the best technique for developing a model of canine CKD with persistent uremia. The dog in this model became uremic and remained stable for a long time which would allow experimental manipulation.

Identification of pathognomonic purine synthesis biomarkers by metabolomic profiling of adolescents with obesity and type 2 diabetes

The incidence of type 2 diabetes is increasing more rapidly in adolescents than in any other age group. We identified and compared metabolite signatures in obese children with type 2 diabetes (T2D), obese children without diabetes (OB), and healthy, age- and gender-matched normal weight controls (NW) by measuring 273 analytes in fasting plasma and 24-hour urine samples from 90 subjects by targeted LC-MS/MS. Diabetic subjects were within 2 years of diagnosis in an attempt to capture early-stage disease prior to declining renal function. We found 22 urine metabolites that were uniquely associated with T2D when compared to OB and NW groups. The metabolites most significantly elevated in T2D youth included members of the betaine pathway, nucleic acid metabolism, and branched-chain amino acids (BCAAs) and their catabolites. Notably, the metabolite pattern in OB and T2D groups differed between urine and plasma, suggesting that urinary BCAAs and their intermediates behaved as a more specific biomarker for T2D, while plasma BCAAs associated with the obese, insulin resistant state independent of diabetes status. Correlative analysis of metabolites in the T2D signature indicated that betaine metabolites, BCAAs, and aromatic amino acids were associated with hyperglycemia, but BCAA acylglycine derivatives and nucleic acid metabolites were linked to insulin resistance. Of major interest, we found that urine levels of succinylaminoimidazole carboxamide riboside (SAICA-riboside) were increased in diabetic youth, identifying urine SAICA-riboside as a potential biomarker for T2D.

MP54-13 METABOLIC DISTURBANCES DURING TOPIRAMATE USE AND THEIR REVERSIBILITY FOLLOWING DRUG CESSATION

You have accessJournal of UrologyStone Disease: Epidemiology & Evaluation II (MP54)1 Sep 2021MP54-13 METABOLIC DISTURBANCES DURING TOPIRAMATE USE AND THEIR REVERSIBILITY FOLLOWING DRUG CESSATION Daniel Pelzman, Eman Kazi, and Michelle Semins Daniel PelzmanDaniel Pelzman More articles by this author , Eman KaziEman Kazi More articles by this author , and Michelle SeminsMichelle Semins More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002084.13AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Topiramate is a commonly used medication which inhibits carbonic anhydrase, causing renal tubular acidosis and hypocitraturia, thereby increasing the risk for kidney stone formation. Despite the strong association between topiramate use and kidney stone formation, few studies have examined the characteristics of stone formers taking topiramate. Additionally, the reversibility of the metabolic disturbances with cessation of the medication has not been previously studied. To fill this knowledge gap, we investigated the stone composition and 24-hour urine samples of a large cohort of stone formers taking topiramate. METHODS: All progress notes written by 5 endourologists from a single academic center were retrospectively reviewed from January 2010 to July 2020 containing the words “topiramate” or “topamax.” Inclusion criteria were age >18 and presence of either a 24-hour urine sample or stone analysis while on topiramate. In addition, a subgroup of 17 patients with 24-hour urine samples before and after stopping topiramate were identified. RESULTS: A total of 93 patients were identified and included for final analysis. Twenty-four hour urine samples were available in 65 patients and showed mean citrate excretion of 333 mg/day (95% confidence interval (CI) [254-412]), mean pH of 6.54 (95% CI [6.41-6.68]), and mean calcium phosphate supersaturation of 1.8 (95% CI [1.6-2.1]). In the subgroup analysis, mean urinary citrate excretion increased from 233 mg/day (95% CI [135-330]) to 633 mg/day (95% CI [471-796], p<0.01), and pH decreased from 6.61 (95% CI [6.34-6.89]) to 6.34 (95% CI [6.12-6.56], p=0.06) after stopping topiramate (Figure 1). 114 stone events occurred in 73 distinct patients with 50% either pure or majority (≥50%) calcium phosphate by composition. CONCLUSIONS: Hypocitraturia and elevated pH is seen during topiramate use with resultant higher rate of calcium phosphate stone formation compared to the general population. Stopping topiramate leads to significant increase in citrate excretion and normalization of pH. Patients and providers should be aware of this risk when starting topiramate therapy. These metabolic disturbances appear to be reversible with medication cessation. Source of Funding: None © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e954-e954 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Daniel Pelzman More articles by this author Eman Kazi More articles by this author Michelle Semins More articles by this author Expand All Advertisement Loading ...

Association Between Blood Pressure and Branched-Chain/Aromatic Amino Acid Excretion Rate in 24-Hour Urine Samples from Elderly Hypertension Patients.

BackgroundRecently, the association between lifestyle-related diseases and free amino acids in the blood plasma—especially branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs)—has been highlighted. However, few studies have been carried out on 24-hour urine samples. Therefore, we aimed to explore the relationships between 24-hour urinary BCAAs and AAAs excretion rate and blood pressure (BP) in elderly patients with hypertension.Methods and ResultsEach of the 322 elderly patients with hypertension completed an in-person questionnaire interview, underwent a physical examination, and provided a 24-hour urine specimen. We measured their BCAAs and AAAs excretion rate, and used multiple linear regression analysis with variable selection to construct models describing the relationships between their BCAAs and AAAs excretion rate and BP. After adjusted for age, gender, height, and weight, valine was inversely associated with both systolic blood pressure (SBP) (β: −0.232, 95% CI: −0.16, −0.006) and diastolic blood pressure (DBP) (β: −0.144, 95% CI: −0.089, −0.005). These findings were invariant even following adjustment for urine volume and drugs history, and Ile was positively associated with DBP (β: 0.170, 95% CI: 0.001, 0.066).ConclusionThe data revealed that the excretion rate of 24-hour urinary BCAAs was closely related to BP in elderly hypertension patients, and these findings will provide new insights into the association between BACC metabolism and BP.

Fractional urinary fluoride excretion in 1.5-3-year-old children

Currently, due to the lack of data a unified fractional urinary F excretion (FUFE) of 45% is used for all children under 7 yo to assess F intake based on urinary fluoride excretion; the study aimed to investigate FUFE in young children under conditions of varying total daily F intake (TDFI). The study recruited 15 children residing in an institution aged 1.5-3.0 years. The material was collected during six two-week periods with different TDFIs: regular and supplemented with table salt with [F] = 150, 200, 250, 300 or 350 mg/kg (in compliance with local regulations). TDFI was assessed through the calculation method of ingested water, food, F-salt and F-toothpaste; the data was obtained through observation. Daily urinary F excretion (DUFE) was assessed through F analysis of 24-hour urine samples using a F-ion-selective electrode. The data were classified into three groups according to children's TDFI level: 1) 0.050-0.149 mgF/kg; 2) 0.150-0.223 mgF/kg; 3) 0.224-0.300 mgF/kg. FUFE was calculated as the ratio between DUFE and TDFI. For statistical analysis, Wilcoxon's t-test was used. In group 1, children had DUFE±SD = 312±187 μgF, in group 2 – 512±162 μgF, in group 3 – 501±185 μgF. FUFE was 0.23±0.03; 0.21±0.07 and 0.16±0.06, respectively (p12<0.01; p13<0.01; p23>0.05). In 1.5-3-year-old children FUFE approaches 23% with a TDFI close to optimal and decreases with a higher TDFI. This is important to consider when calculating TDFI based on FUFE to avoid underestimating the risk of iatrogenic fluorosis.

Monitoring Human Exposure to Organophosphate Esters: Comparing Silicone Wristbands with Spot Urine Samples as Predictors of Internal Dose.

Silicone wristbands present a noninvasive exposure assessment tool and an alternative to traditional biomonitoring; however, questions about their utility remain as validation studies are limited. We sought to determine if wristbands provide quantitative estimates of internal organophosphate ester (OPE) exposure. We evaluated internal dose by measuring metabolite masses excreted in 24-hour urine samples collected over five days among ten adults. We compared internal dose to OPE concentrations in paired wristbands worn during collection and, as a comparison, evaluated metabolite levels in spot urine samples. Three of six OPE metabolites evaluated were detected in >98% of urine samples, and 24 of 34 assessed OPEs were detected in at least one wristband. OPE uptake in wristbands was linear over time (range=0.54-61.8 ng/g/day). OPE concentrations in spot urine and wristbands were not correlated with total diphenyl phosphate (DPHP) excreted in urine, which may be due to the range of possible DPHP parent compounds or dietary exposure. However, for tris-(1,3-dichloro-2-propyl)phosphate (TDCIPP) and tris-(2-chloroisopropyl)phosphate (TCIPP), wristbands and spot urine samples were both moderately to strongly correlated with internal dose (all rs>0.56 and p<0.1), suggesting both perform well as integrated exposure estimates. Given the potential advantages of silicone wristbands, further studies investigating additional compounds are warranted.

Is there a relationship between dietary sodium and potassium intake and clinical findings of a migraine headache?

Few studies have assessed the association between sodium (Na) and potassium (K) and migraine headaches. In this study, we aimed to examine the relationship between 24-hour urine Na and K intakes and clinical findings of migraine in an Iranian sample. In this cross-sectional study, 262 participants, aged 20-50 years, were included with a body mass index (BMI) of 18·5-30 kg/m2and a diagnosis of migraine. One 24-hour urine sample was collected from each subject to estimate the Na and K intakes. The clinical features of migraine, including frequency, duration, severity, Migraine Headache Index Score (MHIS), and Headache Impact Test (HIT) score, were assessed. Besides, a multiple linear regression analysis was performed, and beta estimates and the corresponding 95% confidence intervals (CIs) were reported. Overall, 224 women and 38 men, with a mean age of 36·10 years and BMI of 25·55 kg/m2 comprised our study population. After controlling for potential confounders, the 24-hour urine Na was positively associated with a longer headache duration (β = 0·29; 95% CI: 0·06, 0·53) in the group with the highest urine Na levels as compared to the group with the lowest levels. After adjustments for potential confounders, an increase of 13·05 in the MHIS was observed when the 24-hour urine Na level increased from the first to the third tertile (β = 13·05; 95% CI: 1·70, 24·41). Our findings suggested that a higher 24-hour urine Na level was positively associated with a longer duration of migraine headaches and a higher MHIS.

Comparison of 24-hour versus random urine samples for determination and quantification of Bence Jones protein in a South African population

BackgroundThe International Myeloma Working Group and College of American Pathologists recommend a 24-h urine collection to determine the Bence Jones protein (BJP) excretion level for monitoring treatment response in patients with multiple myeloma (MM). There are several issues related to sample collection and the method is prone to inaccuracy.ObjectiveThis study compared measured 24-h to random urine collections for the quantitation of BJP in a South African population.MethodsSixty-six patients with MM submitted random urine samples with their routine 24-h urine collection from April 2016 – March 2018. Measured 24-h urine BJP was compared to two estimated 24-h BJP excretions calculated as follows: Estimation 1 (E1): Estimated 24-h BJP (mg/24 h) = Urine BJP/Creatinine ratio (mg/mmol) × 10. Estimation 2 (E2): Estimated 24-h BJP (mg/24 h) = Urine BJP/Creatinine ratio (mg/mmol) × 15 mg/kg for women or × 20 mg/kg for men.ResultsCorrelation of estimation equations E1 and E2 to the measured 24-h urine BJP was 0.893. Patients showed no difference in classification of treatment response using either the E1 or E2 estimation equations when compared to the measured 24-h urine BJP results.ConclusionThis study demonstrates that the estimated 24-h BJP shows a high degree of correlation with the measured 24-h BJP and can likely be used to monitor treatment response in South African patients with MM.

Huayu Tongluo Recipe Attenuates Renal Oxidative Stress and Inflammation through the Activation of AMPK/Nrf2 Signaling Pathway in Streptozotocin- (STZ-) Induced Diabetic Rats.

Diabetic nephropathy (DN), a severe microvascular complication of diabetes, is one of the leading causes of end-stage renal disease. Huayu Tongluo Recipe (HTR) has been widely used in the clinical treatment of DN in China, and its efficacy is reliable. This study aimed to explore the renoprotective effect of HTR and the underlying mechanism. Male Sprague-Dawley rats were fed with high sugar and fat diet combined with an intraperitoneal injection of STZ to establish the diabetic model. Rats in each group were respectively given drinking water, HTR, and irbesartan by gavage for 16 weeks. 24-hour urine samples were collected every 4 weeks to detect the content of total protein and 8-OHdG. Blood samples were taken to detect biochemical indicators and inflammatory markers at the end of 16th week. Renal tissue was collected to investigate pathological changes and to detect oxidative stress and inflammatory markers. AMPK/Nrf2 signaling pathway and fibrosis-related proteins were detected by immunohistochemistry, immunofluorescence, real-time PCR, and western blot. 24h urine total protein (24h UTP), serum creatinine (Scr), blood urea nitrogen (BUN), total cholesterol (TC), and triglyceride (TG) were decreased in the rats treated with HTR, while there was no noticeable change of blood glucose. HTR administration decreased malondialdehyde (MDA) content and increased superoxide dismutase (SOD) activity in kidneys, complying with reduced 8-OHdG in the urine. The levels of TNF-α, IL-1β, and MCP1 and the expression of nuclear NFκB were also lower after HTR treatment. Furthermore, HTR alleviated pathological renal injury and reduced the accumulation of extracellular matrix (ECM). Besides, HTR enhanced the AMPK/Nrf2 signaling and increased the expression of HO-1 while it inhibited the Nox4/TGF-β1 signaling in the kidneys of STZ-induced diabetic rats. HTR can inhibit renal oxidative stress and inflammation to reduce ECM accumulation and protect the kidney through activating the AMPK/Nrf2 signaling pathway in DN.

Assessment of sodium and iodine intake among university students in Casablanca, Morocco

IntroductionIodine deficiency is still a matter of public health concern despite salt fortification and especially with global recommendations to lower salt intake, this is mainly due to dietary habits. University students have a diet based on street food high in sodium and low in other micronutrients (i.e. iodine and potassium). In this study, we aim to measure sodium and iodine levels in university students to assess their risk of developing complications later in life. MethodologyA sample of 120 students aged between 18 and 25 years old was recruited and asked to collect their 24-hours urine samples in special containers containing. Samples were stored then analyzed for sodium, potassium, iodine and creatinine levels. ResultsThe average urinary excretion of sodium was 3066.8±1196.0mg/day. Overall, 72.6% of participants consume more than 2g/day of sodium. Average potassium intake is 1805.9±559.4mg/day, and all participants consume less than the adequate amount. Daily urinary excretion of iodine is 135.6±88.9mg/day, and 69.2% of participants consume less than the recommended amount. Sodium, potassium and iodine intakes were higher in male participants (P-values=0.008; 0.044 and 0.003, respectively). The lowest average iodine intake was observed in underweight participants (119.4±31.4) with 87.5% of underweight participants and 80% of female participants below the recommended intake. ConclusionSodium intake is high while iodine intake is low in this studied population, especially in women.

Effect of South Africa's interim mandatory salt reduction programme on urinary sodium excretion and blood pressure.

South Africa implemented legislation in June 2016 mandating maximum sodium (Na) levels in processed foods. A pre-post impact evaluation assessed whether the interim legislative approach reduced salt intake and blood pressure. Baseline Na intake was assessed in a nested cohort of the WHO Study on global AGEing and adult health (WHO-SAGE) Wave 2 (Aug-Dec 2015). 24-hour urine samples were collected in a random subsample (n=1,299; of which n=750 were considered valid (volume≥300mL and creatinine≥4mmol/day (women) or≥6mmol/day (men))). Follow-up urine samples were collected in Wave 3 (Jun 2018-Jun 2019), with replacements included for those lost to follow-up (n=1,189; n=548 valid). In those aged 18 - 49y, median salt intake was 7.8 (4.7, 12.0) g/day in W2 (n=274), remaining similar in the W3 sample (7.7 (4.9, 11.3) g salt/day (n=92); P=0.569). In older adults (50+y), median salt intake was 5.8 (4.0, 8.5) g/day (n=467) in W2, and 6.0 (4.0, 8.6) g/day (n=455) in W3 (P=0.721). Controlling for differences in background characteristics, overall salt intake dropped by 1.15g/day (P=0.028). 24hr urinary Na concentrations from a countrywide South African sample suggest that salt intakes have dropped during the interim phase of mandatory sodium legislation. Further measurement of population level salt intake following stricter Na targets, enforced from June 2019, is necessary.

Novel Application of Nutritional Biomarkers From a Controlled Feeding Study and an Observational Study to Characterization of Dietary Patterns in Postmenopausal Women

Dietary guidance emphasizes healthy dietary patterns, but supporting evidence comes from self-reported dietary data, which are prone to measurement error. We explored whether nutritional biomarkers from the Women's Health Initiative Nutrition and Physical Activity Assessment Study Feeding Study (NPAAS-FS) (n=153; 2010-2014) and the Women's Health Initiative Nutrition and Physical Activity Assessment Study Observational Study (NPAAS-OS) (n=450; 2006-2009) could identify biomarker signatures of dietary patterns for development of corresponding regression calibration equations to help mitigate measurement error. Fasting blood samples were assayed for a specific panel of vitamins, carotenoids, and phospholipid fatty acids; 24-hour urine samples were assayed for nitrogen, sodium, and potassium levels. Intake records from the NPAAS-FS were used to calculate Healthy Eating Index 2010 (HEI-2010), Alternative Healthy Eating Index 2010 (AHEI-2010), alternative Mediterranean diet (aMED), and Dietary Approaches to Stop Hypertension (DASH) scores. Scores were regressed on blood and urine nutritional measures for discovery of dietary pattern biomarkers using a cross-validated model R2 ≥ 36% criterion (stage 1). Next, stepwise models (P≤0.10 for entry/removal) using NPAAS-OS data were used to regress stage 1 dietary pattern biomarkers on NPAAS-OS self-reported dietary pattern scores using a food frequency questionnaire, a 4-day food record, and a 24-hour recall (stage 2). HEI-2010 and aMED analyses met the cross-validated R2 ≥36% criterion in stage 1, while AHEI-2010 and DASH analyses did not. The R2 values for HEI-2010 stage 2 calibration equations were as follows: food frequency questionnaire, 63.5%; 4-day food record, 83.1%; and 24-hour recall, 77.8%. Stage 2 aMED R2 values were 34.9%-46.8%. Dietary pattern biomarkers have potential for calibrating self-reports to enhance studies of diet-disease associations.

Comparing Three Approaches to Salt Intake Assessment Among Lactating Women in Rural Cambodia

ObjectivesMonitoring population salt intake is a critical component of implementing salt fortification programs. In Cambodia, salt is being considered as a vehicle for thiamine fortification to prevent infantile beriberi among breastfed infants. However, salt intake among lactating mothers is not known. The gold standard for assessing sodium intake is repeat 24-hr urinary sodium concentrations. This method has logistical barriers, especially in low-resource settings, and other methods have not been trialed in this population. Here we compare three methods of assessing salt intake in lactating Cambodian women: repeat 24-hr urinary sodium concentrations (USC), repeat 12-hr observed weighed intake records (OWIR), and household salt disappearance (HSD). MethodsData from trial: NCT03616288. Salt intake was assessed using the three methods in a subsample of lactating women (n = 104) between 8 and 22 weeks postpartum. Women were asked to collect two 24-hour urine samples within 7 days. Repeat 12-hr OWIR were collected from women. Household salt disappearance was recorded fortnightly, and was divided by the number of household members to estimate individual intakes. Descriptive household salt use was also recorded. Differences in estimated salt intake from each method were compared using a Kruskal-Wallis test. ResultsMean (95%CI) estimated salt intakes from repeat 24-hr USC, repeat 12-hr OWIR, and HSD were: 9.0 (8.3, 9.8) g/day, 9.1 (7.9, 10.3) g/day, and 10.9 (9.8, 11.9) g/day, respectively. Estimated intakes from HSD were significantly higher than both 24-hr USC (p = 0.009) and 12-hr OWIR (p = 0.002). Estimated intakes from 24-hr USC and 12-hr OWIR were not statistically different (p = 0.6). Salt was being used for purposes other than consumption, such as cleaning fish and vegetables, in 26% of fortnightly visits. ConclusionsRepeat 24-hr USC and 12-hr OWIR are both acceptable and logistically feasible methods of salt intake assessment among lactating women in rural Cambodia. While HSD is a less resource-intensive approach, this method over-estimated salt intake. Salt being used for purposes other than consumption may contribute to over-estimation using this method. Funding SourcesBill & Melinda Gates Foundation, New York Academy of Sciences, Canadian Institutes of Health Research, Research Nova Scotia.

Knowledge, Attitudes, and Behavior Towards Salt Intake and Association With 24-hour Urinary Sodium Excretion in an Adult Population Cohort in Uruguay

ObjectivesTo examine the association between knowledge, attitudes and behavior towards salt use and its consumption estimated by urinary sodium excretion in a population adult cohort from Uruguay (Genotype Phenotype and Environment of Hypertension Study - GEFA-HT-UY). MethodsParticipants [n = 243; age 18–89y (min-max); 61.9% women], provided a single 24-hour urine sample validated according to volume and creatinine excretion. A questionnaire describing knowledge, attitudes and behaviors (KAB) was adapted from the WHO/PAHO protocol for population level sodium determination where participants answered on a range of scales. Anthropometric and blood pressure measurements were also taken. Associations between KAB categories and estimated salt intake were examined by general linear models, adjusted for sex, age tertiles and body mass index (BMI) categories. ResultsConsidering all participants, 35.8% were hypertensive (77% on antihypertensive treatment). Systolic/diastolic blood pressure was 125.6 ± 23.4/79.7 ± 9.9 mmHg, with no difference between sexes. Estimated salt intake was 7.8 ± 3.6 g (3116 ± 1433 mg sodium), higher in men (8.9 ± 3.9 g) compared to women (7.3 ± 3.3 g) (P = 0.0013). Salt intake decreased with age tertiles (P = 0.0001), and increased with BMI categories (P = 0.0067). The majority (88.5%) of participants acknowledge that a high salt diet may cause serious health problems, 92.2% were unaware of WHO salt intake recommendation (<5 g/d) and 78.6% had intake over that limit. Only 12.4% considered they consumed “too much salt”. Although 74.7% reported that limiting salt intake was important for their health, only 56% reported taking regular actions to control its intake. No difference in salt intake was found between participants who considered they use salt “too much” (8.5 ± 0.62 g), “the right amount” (7.9 ± 0.28 g), or “too little” (7.6 ± 0.52 g) (P = 0.56). However, those who reported following a healthy diet had 1.4g lower salt intake than those who reported not doing so (P = 0.016). There was no difference in salt intake between those who reported using/not using salt when cooking (P = 0.65), and adding/not adding salt to food at table (P = 0.087). ConclusionsNo associations were found between knowledge, attitudes and behaviors towards salt use and intake. Perceived salt consumption underestimated salt intake. Funding SourcesCSIC, ANII, Uruguay.

Investigating Fluid Intake in an Underserved Community: What Factors Are Associated with Low Urine Volume on 24-Hour Urine Collection?

Background: Stone prevention is dependent on high fluid intake, with evidence that low urine volume (LUV) can promote nephrolithiasis in the absence of other metabolic abnormalities. Herein, we investigate patient-related factors associated with LUV on initial 24-hour urine collection in an underserved population. Materials and Methods: A retrospective chart review was performed of patients treated by a single surgeon for nephrolithiasis from August 2014 to January 2019. Patients who submitted 24-hour urine samples were divided into two groups based on whether their initial collection was >2 L or not. Factors associated with 24-hour urine volume were analyzed using bivariate and multivariate analyses. As a secondary outcome, we investigated factors associated with corrected 24-hour urine volume on repeat 24-hour urine collection. Results: Two hundred eight patients (45.1%) submitted 24-hour urine collections, 63.9% (133/208) of which demonstrated a urine volume of <2 L. LUV was more common in female patients (77.1% vs 49.5%; p = 0.001) and patients with no insurance and Medicaid (no insurance [100%] vs Medicaid [74.1%] vs Medicare/private [58.6%]; p = 0.02). Female gender and insurance status were independent predictors of LUV in the multivariable analysis. Seventeen of 43 patients (39.5%) with LUV who provided a subsequent collection were able to correct their urine volume. Patients who improved their LUV were older (58.5 vs 45.9 years, p = 0.0149) and more likely to have surgical intervention for their kidney stones (94.1% vs 53.8%, p = 0.006). In our multivariable analysis, surgical intervention was associated with correcting urine volume. Conclusions: Female patients and those with no insurance or Medicaid were more likely to have LUV on an initial 24-hour urine collection. Further research into barriers to fluid intake is important for these two groups, along with directed patient education on strategies for increasing fluid intake.