Validation of 4 Estimating Methods to Evaluate 24-hour Urinary Sodium Excretion for Young Adults in China by Different Seasons

Abstract Background: 24-hour urine sample collection is regarded as the gold standard for sodium intake evaluation, but the implementation can be difficult. To validate and evaluate the accuracy and feasibility of estimating sodium intake by four methods of Kawasaki, INTERSALT, Tanaka and Sun’s equations. Methods: 274 healthy volunteers aged 18-25y were enrolled in this study. 24-hour urine samples as well as timed (morning, afternoon, evening and overnight) urine samples were randomly collected. The sodium intake were estimated by 4 published equations—Kawasaki, INTERSALT Tanaka and Sun’s. The consistencies between estimated sodium intake and real measured values of 24-hour urine sodium excretion were compared by Bland-Altman plots in each of the methods. Taking the variability of sodium excretion in different seasons into account, this study was conducted separately in summer (end of June 2017) and fall (end of November 2017). Results: The 24-h urinary sodium analysis result indicated an average daily sodium intake of 3043.0±1223.3mg in summer, and 3563.7±1370.0mg in the fall. Compared with autumn, the average daily reduction in sodium was about 520.7 mg. From the group level, the mean bias (estimated value - measured value) of the INTERSALT method with morning specimens (-39.7 mg ) was the smallest in summer. The mean bias of Tanaka method for prediction of morning specimens (-149.8 mg ) was the smallest in autumn. For the individual level, the correlation between 24-hour urinary sodium excretion and Sun’s methods was low, with a correlation coefficient of 0.406 in summer and 0.476 in the fall. Correlation coefficients between Kawasaki, INTERSALT, Tanaka methods and 24-hour urinary sodium excretion, respectively was in the range of 0.48-0.64. The correlation coefficient of Kawasaki method was the highest in summer (0.612) while that of Tanaka method with the afternoon specimens was the highest in the autumn (0.635). Conclusions: Estimation of sodium intakes among young adults using the 4 methods have varying degrees of bias and volatility in different times and seasons.

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Abstract P403: Seasonal Variation in the Daily Urinary Sodium Excretion in Outpatients From the Northern Japan

Hypertension ◽

10.1161/hyp.70.suppl_1.p403 ◽

2017 ◽

Vol 70 (suppl_1) ◽

Author(s):

Tomoko Hashimoto

Keyword(s):

Seasonal Variation ◽

Sodium Excretion ◽

Salt Intake ◽

Sodium Intake ◽

Urinary Sodium Excretion ◽

Urinary Sodium ◽

Reliable Estimate ◽

Significant Difference ◽

The Mean ◽

Northern Japan

Although the daily urinary sodium excretion (UNaV) is considered to provide the most reliable estimate of the daily sodium intake, it may be affected by salt loss due to sweating in summer. However, theseasonal variation in the daily UNaV associated with a normal lifestyle is unknown. This study was performed in 348 outpatients from the Morioka region during three seasons: summer(summer 1), winter, and the following summer (summer 2). The daily UNaV (g salt/day) was estimated by the second morning urine method three times during each season. Seasonal variation was defined as a significant trend across the three seasons together with a significant difference between winter and both summers. In women, the daily UNaV was higher in winter (11.8±3.0 g salt/day) than in summer 1 (11.2±2.9g salt/day) or summer 2 (11.0±2.9 g salt/day). In contrast, there was no marked seasonal variation in men. An analysis stratified by age (4 quartiles) identified seasonal variation in the older 2 quartiles of women (aged ≧68 years). In these women, the mean seasonal difference in the daily UNaV was 0.9 g of salt/day for both winter vs. summer 1 and winter vs. summer 2, while it was 0.1-0.8 g of salt/day in the other groups. Seasonal variation in the daily UNaV only occurred in older female patients and was relatively small. This is evidence for restricting salt intake throughout the year and should reassure patients who are anxious about salt loss due to sweating in summer.

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Assessment of Sodium Intake by a Short Dietary Questionnaire

Scandinavian Journal of Social Medicine ◽

10.1177/140349488201000307 ◽

1982 ◽

Vol 10 (3) ◽

pp. 105-112 ◽

Cited By ~ 21

Author(s):

P. Pietinen ◽

A. Tanskanen ◽

J. Tuomilehto

Keyword(s):

Sodium Excretion ◽

Sodium Intake ◽

Urinary Sodium Excretion ◽

Urinary Sodium ◽

Men And Women ◽

Food Items ◽

Salty Food ◽

Frequency Of Use ◽

Heavy Work ◽

The Mean

The aim of the study was to develop a short questionnaire for classifying persons according to their use of salt in public health work. After pretesting the questionnaire it was modified to measure the saltiness of diet. It consisted of five questions concerning certain salting habits and self-rating of salt use, and the frequency of use of seven salty food items. The questionnaire was completed by 1471 persons aged 14 to 65 who also collected one 24-hour urine sample. A sum index of all the questions was formed and called the Salt Index (SI). The correlation between the 24-hour urinary sodium excretion and SI was 0.18 in men and 0.20 in women (both significant at p<0.001). Men and women were classified into three groups according to their SI: low representing the lowest quintile, high representing the highest and medium containing all the other quintiles. The mean 24-hour urinary sodium excretion was lowest in the low SI-category and highest in the high SI-category in both men and women. The subjects were further divided into light and heavy workers on the basis of their occupation. In this analysis the effect of both energy intake and the saltiness of the diet indicated by SI were clearly distinguished. Women doing light work and having a low SI had the lowest sodium excretion value, 148 mmol/day, and men doing heavy work and having a high SI had the highest, 260 mmol/day.

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Association between 24-h urinary sodium and potassium excretion and blood pressure among Chinese adults aged 18–69 years

Scientific Reports ◽

10.1038/s41598-021-83049-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Xiaofu Du ◽

Le Fang ◽

Jianwei Xu ◽

Xiangyu Chen ◽

Yamin Bai ◽

...

Keyword(s):

Blood Pressure ◽

Sodium Excretion ◽

Sodium Intake ◽

Urinary Sodium Excretion ◽

Urinary Sodium ◽

Inverse Association ◽

Potassium Excretion ◽

Chinese Adults ◽

Potassium Intake ◽

Sodium And Potassium

AbstractThe direction and magnitude of the association between sodium and potassium excretion and blood pressure (BP) may differ depending on the characteristics of the study participant or the intake assessment method. Our objective was to assess the relationship between BP, hypertension and 24-h urinary sodium and potassium excretion among Chinese adults. A total of 1424 provincially representative Chinese residents aged 18 to 69 years participated in a cross-sectional survey in 2017 that included demographic data, physical measurements and 24-h urine collection. In this study, the average 24-h urinary sodium and potassium excretion and sodium-to-potassium ratio were 3811.4 mg/day, 1449.3 mg/day, and 4.9, respectively. After multivariable adjustment, each 1000 mg difference in 24-h urinary sodium excretion was significantly associated with systolic BP (0.64 mm Hg; 95% confidence interval [CI] 0.05–1.24) and diastolic BP (0.45 mm Hg; 95% CI 0.08–0.81), and each 1000 mg difference in 24-h urinary potassium excretion was inversely associated with systolic BP (− 3.07 mm Hg; 95% CI − 4.57 to − 1.57) and diastolic BP (− 0.94 mm Hg; 95% CI − 1.87 to − 0.02). The sodium-to-potassium ratio was significantly associated with systolic BP (0.78 mm Hg; 95% CI 0.42–1.13) and diastolic BP (0.31 mm Hg; 95% CI 0.10–0.53) per 1-unit increase. These associations were mainly driven by the hypertensive group. Those with a sodium intake above about 4900 mg/24 h or with a potassium intake below about 1000 mg/24 h had a higher risk of hypertension. At higher but not lower levels of 24-h urinary sodium excretion, potassium can better blunt the sodium-BP relationship. The adjusted odds ratios (ORs) of hypertension in the highest quartile compared with the lowest quartile of excretion were 0.54 (95% CI 0.35–0.84) for potassium and 1.71 (95% CI 1.16–2.51) for the sodium-to-potassium ratio, while the corresponding OR for sodium was not significant (OR, 1.28; 95% CI 0.83–1.98). Our results showed that the sodium intake was significantly associated with BP among hypertensive patients and the inverse association between potassium intake and BP was stronger and involved a larger fraction of the population, especially those with a potassium intake below 1000 mg/24 h should probably increase their potassium intake.

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

Journal of Nutrition ◽

10.1093/jn/nxy211 ◽

2018 ◽

Vol 148 (12) ◽

pp. 1946-1953 ◽

Cited By ~ 6

Author(s):

Magali Rios-Leyvraz ◽

Pascal Bovet ◽

René Tabin ◽

Bernard Genin ◽

Michel Russo ◽

...

Keyword(s):

Sodium Excretion ◽

Salt Intake ◽

Sodium Intake ◽

Population Level ◽

Urinary Sodium Excretion ◽

Cross Sectional Study ◽

Urinary Sodium ◽

Cross Sectional ◽

High Sodium ◽

Individual Level

ABSTRACT Background 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. Objective 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. Methods 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. Results 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. Conclusions 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.

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Effects of hypoproteinemia on renal hemodynamics, arterial pressure, and fluid volume

AJP Renal Physiology ◽

10.1152/ajprenal.1987.252.1.f91 ◽

1987 ◽

Vol 252 (1) ◽

pp. F91-F98

Author(s):

R. D. Manning

Keyword(s):

Mean Arterial Pressure ◽

Arterial Pressure ◽

Sodium Excretion ◽

Sodium Intake ◽

Renal Plasma Flow ◽

Urinary Sodium Excretion ◽

Renal Hemodynamics ◽

Fluid Volume ◽

Urinary Sodium ◽

Plasma Aldosterone Concentration

The effects of long-term hypoproteinemia on renal hemodynamics, arterial pressure, and fluid volume were studied in eight conscious dogs over a 34-day period. Plasma protein concentration (PPC) was decreased by daily plasmapheresis, and the effects of decreasing and increasing sodium intake were measured. By the 12th day of plasmapheresis, during which sodium intake was 30 meq/day, PPC had decreased to 2.5 g/dl from a control value of 7.2 g/dl, mean arterial pressure had decreased to 78% of control, glomerular filtration rate (GFR) was 75.2% of control, and urinary sodium excretion was decreased. By day 18 of plasmapheresis, estimated renal plasma flow (ERPF) was decreased to 60% of control due to the decreased arterial pressure and an increase in renal vascular resistance. Also, plasma renin activity and plasma aldosterone concentration were both increased, and the relationship between mean arterial pressure and urinary sodium excretion was distinctly shifted to the left along the arterial pressure axis. In contradistinction to acute experiments, chronic hypoproteinemia results in decreases in GFR, ERPF, and urinary sodium excretion and has marked effects on both fluid volume and arterial pressure regulation.

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Sodium Status and Its Association with Overweight and Obesity in Adults Living in Yazd, Iran

Journal of Nutrition and Food Security ◽

10.18502/jnfs.v4i3.1311 ◽

2019 ◽

Author(s):

Abolfazl Dashti- Rahmat Abadi ◽

Hassan Mozaffari- Khosravi ◽

Mahdieh Nemayandeh ◽

Mohammad Hosein Soltani ◽

Masoud Mirzaei ◽

...

Keyword(s):

Sodium Excretion ◽

Smoking Status ◽

Urinary Sodium Excretion ◽

Overweight And Obesity ◽

Urinary Sodium ◽

Health Study ◽

Significant Difference ◽

History Of ◽

The Mean ◽

Relationship Of

Background: Studies on the relationship of urinary sodium with overweight and obesity led to controversial results. Furthermore, no study has ever investigated the association between sodium status and obesity in Iranian adults. The present study examined the association of urinary sodium levels with overweight and obesity in adults living in Yazd, Iran. Methods: The present study recruited 240 adults randomly selected from adults, who participated in Yazd Health Study (YaHS). A 24-hour urine sample was collected from the participants. Participants' demographic information, history of chronic diseases, and smoking status were obtained. The height and weight of the participants were also assessed using standard methods. We compared the weight and body mass index (BMI) of the participants based on the urinary sodium excretion tertiles. The logistic regression model in crude and multivariable adjusted models was used to compare the odds of obesity between urinary sodium tertiles. Results: The findings showed that the mean urinary sodium was not significantly different among overweight, obese, and individuals with normal BMI (P > 0.05) using the crude and multivariable models. Furthermore, no significant difference was observed in the mean BMI according to urinary sodium excretion tertiles. In addition, the analyses showed that the sodium status was not significantly associated with odds of developing obesity in crude and in multivariable adjusted models. Conclusion: No significant relationship was seen between sodium status and overweight or obesity. Future prospective studies are highly recommended to confirm these results.

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24-Hour vs. Spot Urinary Sodium and Potassium Measurements in Adult Hypertensive Patients: A Cohort Validation Study

American Journal of Hypertension ◽

10.1093/ajh/hpz104 ◽

2019 ◽

Vol 32 (10) ◽

pp. 983-991

Author(s):

Elizabeth R Wan ◽

Jennifer Cross ◽

Reecha Sofat ◽

Stephen B Walsh

Keyword(s):

Sodium Excretion ◽

Sodium Intake ◽

Urinary Sodium Excretion ◽

Sodium Concentration ◽

Serum Biochemistry ◽

Urinary Sodium ◽

Hypertensive Patients ◽

Spot Urine ◽

Sodium Ingestion ◽

Weak Negative Correlation

Abstract BACKGROUND Sodium intake is correlated with the development of hypertension. Guyton’s principals suggest that the 24-hour urinary sodium excretion reflects sodium ingestion over the same period. 24-hour urine collections are arduous to collect, so many centers use spot urinary measurements instead. We compared spot to matched 24-hour urinary electrolyte measurements. METHODS We examined 419 hypertensive patients from the UCL Complex Hypertension Clinic. 77 had matched and complete 24-hour and spot urinary and serum biochemistry to examine. We compared the spot and 24-hour urinary; sodium concentration, Na/Cr ratio, FENa, Kawasaki and Tanaka estimated sodium excretion as well as the potassium concentration, K/Cr ratio, Kawasaki and Tanaka potassium excretion. RESULTS Our cohort was 58% male and the median age was 41 years. The 24-hour and spot Na concentrations correlated moderately (r = 0.4633, P < 0.0001). The 24-hour and spot Na/creatinine ratios correlated weakly (r = 0.2625, P = 0.0194). The 24-hour and spot FENa results showed a weak negative correlation (r = −0.222, P = ns). The 24-hour sodium excretion and the Kawasaki-derived spot urine sodium excretion correlated moderately (r = 0.3118, P = 0.0052). All Bland–Altman analyses showed poor agreement. The 24-hour and spot potassium concentrations correlated very poorly (r = 0.1158, P = ns). The 24-hour and spot urinary K/creatinine ratios correlated weakly (r = 0.47, P ≤ 0.0001). 24-hour and Kawasaki and Tanaka estimated potassium excretions correlated much better (r = 0.58, P < 0.0001). CONCLUSIONS Spot urinary measurements of sodium give a very poor understanding of the natriuresis occurring over the same 24-hour period. The Kawasaki and Tanaka estimations of the 24-hour sodium excretion showed a much lower correlation than previously reported.

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Effects of within-person variability in spot urinary sodium measurements on the associations with blood pressure and risk of cardiovascular disease in 0.5 Million adults in UK Biobank

European Heart Journal ◽

10.1093/ehjci/ehaa946.2857 ◽

2020 ◽

Vol 41 (Supplement_2) ◽

Author(s):

J Carter ◽

F Re ◽

I Hammami ◽

T Littlejohns ◽

M Arnold ◽

...

Keyword(s):

Blood Pressure ◽

Cardiovascular Disease ◽

Sodium Excretion ◽

Cox Regression ◽

Sodium Intake ◽

Urinary Sodium Excretion ◽

Urinary Sodium ◽

World Health ◽

Funding Source ◽

Uk Biobank

Abstract Background Randomised control trials have demonstrated direct positive and causal associations of 24-hr measurements of urinary sodium excretion on blood pressure. However, prospective studies, which often used spot (not 24-hr) measurements of urinary sodium, have reported J-shaped associations with higher risks of cardiovascular disease (CVD) at sodium intake <4 g/day. The reasons for the discrepant results are not fully understood, but have prompted some to question the World Health Organisation's recommendations to restrict sodium intake to <2.3g/day. Purpose We examined the effects of within-person variability in spot urinary sodium (UNa) measurements on immediate and delayed associations of UNa with blood pressure at baseline and at resurvey, and with incident cardiovascular disease in the UK Biobank (UKB). Methods Baseline spot urine samples were measured in 502,619 adults at baseline and in 20,346 participants who were resurveyed at 4 years after baseline. Linear regression was used to assess associations of baseline UNa measurements with systolic blood pressure (SBP; mmHg) at baseline and at resurvey. Cox regression was used estimate the associations between baseline measures of UNa with incident CVD events (recorded from linkage with hospital records). All analyses were adjusted for confounders and corrected for regression dilution bias. Results After excluding participants with prevalent diseases, the primary analyses involved 386,060 adults who were followed-up for a median of 7.8 years, during which ∼13,000 CVD events occurred. Estimated mean (SD) urinary sodium excretion was 77.4 mmol/L (SD 44.4, IQR = 42.8–103.7 mmol/L), and mean SBP/DBP were 137.5/82.3 (SD 18.5/10.1) mmHg, respectively. Within-person variability in UNa was high, with a self-correlation of 0.35 at 4 years between measurements. After adjustment for confounders and correction for regression dilution bias, a 100 mmol/L higher UNa was associated with an immediate 3.2 mmHg higher SBP (95% confidence interval [CI]: 2.8–3.6) in cross-sectional analyses (Figure 1). However, the corresponding associations of baseline UNa with SBP at resurvey was completely attenuated (p=0.20). The predicted risk of CVD was 1.06 (95% CI 1.06–1.07, p<0.001) for a 3.2 mmHg higher SBP, but the observed risk for a 100 mmol/L higher UNa was 0.95 (95% CI 0.82–1.10, p=0.47) (Figure 1). Conclusions While spot measurements of UNa were strongly associated with immediate effects on SBP, the magnitude of within-person variability in UNa precluded detection of associations with SBP several years after baseline or with risk of CVD. The extreme within-person variability in spot UNa may explain the discrepant results of the trials and observational studies of sodium and blood pressure. Figure 1. Spot UNa with SBP and CVD in UK Biobank Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Core funding from the Medical Research Council-Population Health Research Unit, British Heart Foundation

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