Assessment of Foods Associated with Sodium and Potassium Intake in Japanese Youths Using the Brief-Type Self-Administered Diet History Questionnaire

The identification of sodium and potassium intake in youths is an important step to preventing the increase of blood pressure in childhood. We examined food intake and estimated mineral intake using a brief-type self-administered diet history questionnaire (BDHQ) to test its validity as a comparison with urinary excretion in Japanese youths. The subjects were 5th and 8th graders (n = 2377), who completed the BDHQ and permitted the use of their overnight urine specimens. Sodium intake was poorly associated with sodium excretion (Rho = 0.048), and the coefficients of dietary potassium and a sodium-to-potassium molar ratio were 0.091–0.130. Higher soybean paste (miso) intake and pickles were significantly associated with higher sodium excretion (p ≤ 0.005). However, these foods were positively associated with potassium excretion (p = 0.002–0.012), and not associated with an excreted sodium-to-potassium ratio. Fruits and dairy products were positively associated (p ≤ 0.048), whereas beverages were negatively associated with potassium excretion (p ≤ 0.004). The association of the sodium-to-potassium ratio was opposite to that of potassium (p ≤ 0.001). The choice of foods, potassium, and the sodium-to-potassium ratio assessed using the BDHQ are available as part of health education for youths, but the assessment of sodium intake in population levels should be carefully conducted.

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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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Twenty-Four–Hour Urinary Sodium and Potassium Excretion and Their Associations With Blood Pressure Among Adults in China

Hypertension ◽

10.1161/hypertensionaha.120.15238 ◽

2020 ◽

Vol 76 (5) ◽

pp. 1580-1588

Author(s):

Yuan Li ◽

Puhong Zhang ◽

Jing Wu ◽

Jixiang Ma ◽

Jianwei Xu ◽

...

Keyword(s):

Blood Pressure ◽

Sodium Intake ◽

Molar Ratio ◽

Baseline Survey ◽

Potassium Excretion ◽

Unique Identifier ◽

Potassium Intake ◽

Link Type ◽

Unit Increase ◽

Sodium And Potassium

This study aimed to assess current level of sodium and potassium intake and their associations with blood pressure (BP) using the 24-hour urinary data in a large sample of China. Data from participants aged 18 to 75 years were collected as the baseline survey of Action on Salt China in 2018. Of 5454 adults, 5353 completed 24-hour urine collection. The average sodium, potassium excretion, and sodium-to-potassium molar ratio were 4318.1±1814.1 mg/d (equivalent to 11.0±4.6 g/d of salt), 1573.7±627.1 mg/d, and 5.0±2.1, respectively. After adjusting for potential confounding factors and correcting for regression dilution, each 1000-mg increase in sodium excretion was associated with increased systolic BP (1.32 mm Hg [95% CI, 0.92–1.81]) and diastolic BP (0.34 mm Hg [95% CI, 0.09–0.60]). Each 1000-mg increase in potassium excretion was inversely associated with systolic BP (−3.19 mm Hg [95% CI, −4.38 to −2.20]) and diastolic BP (−1.56 mm Hg [95% CI, −2.29 to −0.90]). Each unit increase in sodium-to-potassium molar ratio was associated with an increase of systolic BP by 1.21 mm Hg (95% CI, 0.91–1.60) and diastolic BP by 0.44 mm Hg (95% CI, 0.24–0.64). The relationships between sodium and BP mostly increase with the rise of BP quantiles. Potassium shows the opposite trend. The current sodium intake in Chinese adults remains high and potassium intake is low. Sodium and sodium-to-potassium ratio were positively associated with BP, whereas potassium was inversely associated with BP. Registration— URL: https://tinyurl.com/vdr8rpr ; Unique identifier: ChiCTR1800017553. URL: https://tinyurl.com/w8c7x3w ; Unique identifier: ChiCTR1800016804. URL: https://tinyurl.com/s3ajldw ; Unique identifier: ChiCTR1800018119.

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Urinary Sodium and Potassium, and Risk of Ischaemic and Haemorrhagic Stroke (INTERSTROKE): a case-control study

American Journal of Hypertension ◽

10.1093/ajh/hpaa176 ◽

2020 ◽

Author(s):

Conor Judge ◽

Martin J O’Donnell ◽

Graeme J Hankey ◽

Sumathy Rangarajan ◽

Siu Lim Chin ◽

...

Keyword(s):

Ischemic Stroke ◽

Sodium Excretion ◽

Stroke Risk ◽

Sodium Intake ◽

Urinary Sodium ◽

Potassium Excretion ◽

High Potassium ◽

Potassium Intake ◽

Low Sodium ◽

Sodium And Potassium

Abstract Background Although low sodium intake (<2g/day) and high potassium intake (>3·5g/day) are proposed as public health interventions to reduce stroke risk, there is uncertainty about the benefit and feasibility of this combined recommendation on prevention of stroke and its subtypes. Methods We obtained random urine samples from 9,275 cases of acute first stroke and 9,726 matched controls (8,761 matched pairs for conditional analysis) from 27 countries and estimated the 24-hour sodium and potassium excretion, a surrogate for intake, using the Tanaka formula. Using multivariable conditional logistic regression, we determined the associations of estimated 24-hour urinary sodium and potassium excretion with stroke and its subtypes. Results The mean estimated 24-hour sodium and potassium urinary excretion was 3·29g/day and 1·57g/day, with 0·01% of participants having both low sodium (<2·0g/day) and high potassium excretion (>3·5g/day). There was a moderate positive correlation between sodium and potassium excretion (r=0·4435, P<0.001) and between sodium excretion and blood pressure (P<0.001). Compared with an estimated urinary sodium excretion of 2·8-3·5g/day (second quartile, reference), higher (>4·26g/day) (OR 1.81;95%CI,1.65-2.00) and lower (<2·8g/day) sodium excretion (OR 1.39;95%CI,1.26-1.53) were significantly associated with increased risk of stroke. The stroke risk associated with the highest quartile of sodium intake (sodium excretion >4·26g/day) was significantly greater (P<0.001) for intracerebral haemorrhage (ICH) (OR 2.38;95%CI,1.93-2.92) than for ischemic stroke (OR 1.67;95%CI,1.50-1.87), and greater for large vessel and small vessel ischemic stroke than for cardioembolic ischemic stroke. Urinary potassium was inversely and linearly associated with risk of stroke, and stronger for ischemic stroke than ICH (P=0.026). In an analysis of combined sodium and potassium excretion, the combination of high potassium intake (>1·58g/day) and moderate sodium intake (2.8-3.5 g/day) was associated with the lowest risk of stroke. Conclusion The association of sodium intake and stroke is J-shaped, with high sodium intake a stronger risk factor for intracerebral haemorrhage than ischemic stroke. Our data suggest that moderate sodium intake – rather than low sodium intake – combined with high potassium intake may be associated with the lowest risk of stroke and expected to be a more feasible combined dietary target.

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Genome-Wide Association Meta-Analysis of Individuals of European Ancestry Identifies Suggestive Loci for Sodium Intake, Potassium Intake, and Their Ratio Measured from 24-Hour or Half-Day Urine Samples

Journal of Nutrition ◽

10.1093/jn/nxaa241 ◽

2020 ◽

Vol 150 (10) ◽

pp. 2635-2645

Author(s):

Minjung Kho ◽

Jennifer A Smith ◽

Niek Verweij ◽

Lulu Shang ◽

Kathleen A Ryan ◽

...

Keyword(s):

Sodium Excretion ◽

Sodium Intake ◽

Meta Analysis ◽

Urine Samples ◽

European Ancestry ◽

Potassium Excretion ◽

Potassium Intake ◽

Genome Wide ◽

Genomic Regions ◽

Sodium And Potassium

ABSTRACT Background Excess sodium intake and insufficient potassium intake are risk factors for hypertension, but there is limited knowledge regarding genetic factors that influence intake. Twenty-hour or half-day urine samples provide robust estimates of sodium and potassium intake, outperforming other measures such as spot urine samples and dietary self-reporting. Objective The aim of this study was to investigate genomic regions associated with sodium intake, potassium intake, and sodium-to-potassium ratio measured from 24-h or half-day urine samples. Methods Using samples of European ancestry (mean age: 54.2 y; 52.3% women), we conducted a meta-analysis of genome-wide association studies in 4 cohorts with 24-h or half-day urine samples (n = 6,519), followed by gene-based analysis. Suggestive loci (P < 10−6) were examined in additional European (n = 844), African (n = 1,246), and Asian (n = 2,475) ancestry samples. Results We found suggestive loci (P < 10−6) for all 3 traits, including 7 for 24-h sodium excretion, 4 for 24-h potassium excretion, and 4 for sodium-to-potassium ratio. The most significant locus was rs77958157 near cocaine- and amphetamine-regulated transcript prepropeptide (CARTPT) , a gene involved in eating behavior and appetite regulation (P = 2.3 × 10−8 with sodium-to-potassium ratio). Two suggestive loci were replicated in additional samples: for sodium excretion, rs12094702 near zinc finger SWIM-type containing 5 (ZSWIM5) was replicated in the Asian ancestry sample reaching Bonferroni-corrected significance (P = 0.007), and for potassium excretion rs34473523 near sodium leak channel (NALCN) was associated at a nominal P value with potassium excretion both in European (P = 0.043) and African (P = 0.043) ancestry cohorts. Gene-based tests identified 1 significant gene for sodium excretion, CDC42 small effector 1 (CDC42SE1), which is associated with blood pressure regulation. Conclusions We identified multiple suggestive loci for sodium and potassium intake near genes associated with eating behavior, nervous system development and function, and blood pressure regulation in individuals of European ancestry. Further research is needed to replicate these findings and to provide insight into the underlying genetic mechanisms by which these genomic regions influence sodium and potassium intake.

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Joint association of urinary sodium and potassium excretion with cardiovascular events and mortality: prospective cohort study

BMJ ◽

10.1136/bmj.l772 ◽

2019 ◽

pp. l772 ◽

Cited By ~ 25

Author(s):

Martin O’Donnell ◽

Andrew Mente ◽

Sumathy Rangarajan ◽

Matthew J McQueen ◽

Neil O’Leary ◽

...

Keyword(s):

Urinary Excretion ◽

Sodium Excretion ◽

Cardiovascular Events ◽

Sodium Intake ◽

Urinary Sodium ◽

Potassium Excretion ◽

High Potassium ◽

High Sodium ◽

Low Sodium ◽

Sodium And Potassium

AbstractObjectiveTo evaluate the joint association of sodium and potassium urinary excretion (as surrogate measures of intake) with cardiovascular events and mortality, in the context of current World Health Organization recommendations for daily intake (<2.0 g sodium, >3.5 g potassium) in adults.DesignInternational prospective cohort study.Setting18 high, middle, and low income countries, sampled from urban and rural communities.Participants103 570 people who provided morning fasting urine samples.Main outcome measuresAssociation of estimated 24 hour urinary sodium and potassium excretion (surrogates for intake) with all cause mortality and major cardiovascular events, using multivariable Cox regression. A six category variable for joint sodium and potassium was generated: sodium excretion (low (<3 g/day), moderate (3-5 g/day), and high (>5 g/day) sodium intakes) by potassium excretion (greater/equal or less than median 2.1 g/day).ResultsMean estimated sodium and potassium urinary excretion were 4.93 g/day and 2.12 g/day, respectively. After a median follow-up of 8.2 years, 7884 (6.1%) participants had died or experienced a major cardiovascular event. Increasing urinary sodium excretion was positively associated with increasing potassium excretion (unadjusted r=0.34), and only 0.002% had a concomitant urinary excretion of <2.0 g/day of sodium and >3.5 g/day of potassium. A J-shaped association was observed of sodium excretion and inverse association of potassium excretion with death and cardiovascular events. For joint sodium and potassium excretion categories, the lowest risk of death and cardiovascular events occurred in the group with moderate sodium excretion (3-5 g/day) and higher potassium excretion (21.9% of cohort). Compared with this reference group, the combinations of low potassium with low sodium excretion (hazard ratio 1.23, 1.11 to 1.37; 7.4% of cohort) and low potassium with high sodium excretion (1.21, 1.11 to 1.32; 13.8% of cohort) were associated with the highest risk, followed by low sodium excretion (1.19, 1.02 to 1.38; 3.3% of cohort) and high sodium excretion (1.10, 1.02 to 1.18; 29.6% of cohort) among those with potassium excretion greater than the median. Higher potassium excretion attenuated the increased cardiovascular risk associated with high sodium excretion (P for interaction=0.007).ConclusionsThese findings suggest that the simultaneous target of low sodium intake (<2 g/day) with high potassium intake (>3.5 g/day) is extremely uncommon. Combined moderate sodium intake (3-5 g/day) with high potassium intake is associated with the lowest risk of mortality and cardiovascular events.

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Estimated 24 Hour Urinary Sodium and Potassium Excretion in a Population of Moroccan Adults

10.21203/rs.3.rs-1146806/v1 ◽

2021 ◽

Author(s):

Mohamed idrissi ◽

Naima Saeid ◽

Samir Mounach ◽

Hicham El Berri ◽

Ayoub Al Jawaldah ◽

...

Keyword(s):

Blood Pressure ◽

Sodium Excretion ◽

Sodium Intake ◽

Eastern Mediterranean Region ◽

Urinary Sodium ◽

World Health ◽

Potassium Excretion ◽

Potassium Intake ◽

Urinary Potassium ◽

The Mean

Abstract Background: Excessive sodium (Na) intake and low potassium (K) intake are associated with adverse cardiovascular health outcomes. Morocco lacks data on actual Na and K intake in adults. The aim of this study was to estimate the mean intake of Na and K in a Moroccan population of adults using the 24-h urinary excretion and to examine their association with blood pressure (BP). Methods: A total of 371 adults, who participated in the urinary validation sub-study of the STEP-wise Survey-Morocco-2017-2018, have complete data on demographic, anthropometric and blood pressure and have provided a valid 24-h urine collection according to the standard protocol of the World Health Organization (WHO). Results: The mean 24-h urinary sodium excretion was 2794 mg (SD, 1394) and the median was 2550 mg (IQR, 1780-3726). The mean 24-h urinary potassium excretion was 1898 mg (SD, 1044) and the median was 1640 mg (IQR, 1170-2410). Sodium excretion was between 3000 and 5000 mg/day in 31% of participants, < 3000 mg/day in 64%, and > 5000 mg/day in only 5%. No significant association of urinary sodium or potassium with blood pressure was found. Conclusion: Sodium intake in the studied population of Moroccan adults was higher than WHO recommendation and was comparable to levels reported in countries from Eastern Mediterranean Region. The vast majority of participants had a sodium intake < 5000 mg/day, with only 5% were above this level. Potassium intake was in the range of 1000 to 3000 mg/day. Within these ranges, there was no association between sodium or potassium intake and blood pressure. This information is crucial to help implement the national strategy to reduce sodium intake as a cost-effective intervention to prevent chronic disease in Morocco.

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Sodium and Potassium Excretion of Schoolchildren and Relationship with Their Family Excretion in China

Nutrients ◽

10.3390/nu13082864 ◽

2021 ◽

Vol 13 (8) ◽

pp. 2864

Author(s):

Yuan Li ◽

Yuewen Sun ◽

Xian Li ◽

Le Dong ◽

Fengzhuo Cheng ◽

...

Keyword(s):

Mixed Models ◽

Sodium Excretion ◽

Cross Sectional Study ◽

Molar Ratio ◽

Potassium Excretion ◽

Cross Sectional ◽

Sodium Potassium ◽

Salt Reduction ◽

The Family ◽

Sodium And Potassium

This cross-sectional study aimed to assess 24-h urinary sodium and potassium excretion in children and the relationships with their family excretion. Using the baseline data of a randomized trial conducted in three cities of China in 2018, a total of 590 children (mean age 8.6 ± 0.4 years) and 1180 adults (mean age 45.8 ± 12.9 years) from 592 families had one or two complete 24-h urine collections. The average sodium, potassium excretion and sodium-to-potassium molar ratio of children were 2180.9 ± 787.1 mg/d (equivalent to 5.5 ± 2.0 g/d of salt), 955.6 ± 310.1 mg/d and 4.2 ± 1.7 respectively, with 77.1% of the participants exceeding the sodium recommendation and 100% below the proposed potassium intake. In mixed models adjusting for confounders, every 1 mg/d increase in sodium excretion of adult family members was associated with a 0.11 mg/d (95% CI: 0.06 to 0.16, p < 0.0001) increase in sodium excretion of children. The family-child regression coefficient corresponds to 0.20 mg/d (95% CI: 0.15 to 0.26, p < 0.0001) per 1 mg/d in potassium and to 0.36 (95% CI: 0.26 to 0.45, p < 0.0001) in sodium-to-potassium molar ratio. Children in China are consuming too much sodium and significantly inadequate potassium. The sodium, potassium excretion and sodium-to-potassium ratio of children are associated with their family excretions in small to moderate extent. Efforts are warranted to support salt reduction and potassium enhancement in children through comprehensive strategies engaging with families, schools and food environments.

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Blood Pressure in relation to 24-Hour Urinary Sodium and Potassium Excretion in a Uruguayan Population Sample

International Journal of Hypertension ◽

10.1155/2018/6956078 ◽

2018 ◽

Vol 2018 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Paula Moliterno ◽

Ramón Álvarez-Vaz ◽

Matias Pécora ◽

Leonella Luzardo ◽

Luciana Borgarello ◽

...

Keyword(s):

Blood Pressure ◽

Cluster Analysis ◽

Systolic Blood Pressure ◽

Sodium Excretion ◽

Urinary Sodium ◽

Potassium Excretion ◽

High Systolic Blood Pressure ◽

High Sodium ◽

Potassium Intake ◽

Sodium And Potassium

Many public health policies in Latin America target an optimized sodium and potassium intake. The aims of this study were to assess the sodium and potassium intake using 24-hour urinary analysis and to study their association with blood pressure in a Uruguayan population cohort using cluster analysis. A total of 149 participants (aged 20–85 years) were included in the study, and office blood pressure, anthropometric measurements, biochemical parameters in the blood, and 24-hour urine samples were obtained. The overall mean sodium and potassium excretion was 152.9 ± 57.3 mmol/day (8.9 ± 3.4 g/day of salt) and 55.4 ± 19.6 mmol/day, respectively. The average office systolic/diastolic blood pressure was 124.6 ± 16.7/79.3 ± 9.9 mmHg. Three compact spherical clusters were defined in untreated participants based on predetermined attributes, including blood pressure, age, and sodium and potassium excretion. The major characteristics of the three clusters were (1) high systolic blood pressure and moderate sodium excretion, (2) moderate systolic blood pressure and very high sodium excretion, and (3) low systolic blood pressure and low sodium excretion. Participants in cluster three had systolic blood pressure values that were 23.9 mmHg (95% confidence interval: −29.5 to −1.84) lower than those in cluster one. Participants in cluster two had blood pressure levels similar to those in cluster one (P = 0.32) and worse metabolic profiles than those in cluster one and three (P < 0.05). None of the clusters showed high blood pressure levels and high sodium excretion. No linear association was found between blood pressure and urinary sodium excretion (r < 0.14; P > 0.47). An effect of sodium and potassium intake on blood pressure levels was not found at the population level using regression or cluster analysis.

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Effects of sodium intake on steady-state potassium excretion

AJP Renal Physiology ◽

10.1152/ajprenal.1984.246.6.f772 ◽

1984 ◽

Vol 246 (6) ◽

pp. F772-F778 ◽

Cited By ~ 1

Author(s):

D. B. Young ◽

T. E. Jackson ◽

U. Tipayamontri ◽

R. C. Scott

Keyword(s):

Steady State ◽

Potassium Concentration ◽

Sodium Intake ◽

Plasma Potassium ◽

Potassium Excretion ◽

Distal Nephron ◽

Concentration Data ◽

Potassium Intake ◽

Independent Variable ◽

The Relationship

The effects of changes in sodium intake on the steady-state relationship between plasma potassium concentration and potassium excretion were studied in 15 chronically adrenalectomized dogs. Throughout the experiments the dogs received aldosterone at a rate of 50 micrograms/day and methylprednisolone at 1 mg/day. The relationship between plasma potassium and steady-state potassium excretion was obtained by changing potassium intake from 10 to 30 to 100 meq/day, each level being maintained for 7-10 days. At the conclusion of each period at a given level of potassium intake, plasma potassium and excretion were measured and plotted, plasma potassium being the independent variable. Such a relationship was obtained while the dogs were on three different levels of sodium intake: 10, 100, and 200 meq/day. The curves from the data obtained at 100 and 200 meq/day sodium intake both were shifted to the left of the curve obtained at 10 meq/day (P less than 0.05), although the 100 and 200 meq/day curves were not different from each other. On the basis of these data one could predict that, at a plasma potassium concentration of 4.0 meq/liter, the animals would excrete potassium at a rate of 17 meq/day on a 10 meq/day sodium intake, 37 meq/day on a 100 meq/day sodium intake, and 47 meq/day on a 200 meq/day sodium intake. Urine flow and electrolyte concentration data are consistent with the hypothesis that the sodium intake effect on potassium excretion was mediated through increases in distal nephron flow rate and decreases in distal nephron potassium concentration.

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Effect of Inheritance and Stress on the Diurnal Excretion of Sodium and Potassium in Young People with and without a Family History of Hypertension

Clinical Science ◽

10.1042/cs059161s ◽

1980 ◽

Vol 59 (s6) ◽

pp. 161s-164s ◽

Cited By ~ 2

Author(s):

P. S. Parfrey ◽

P. Wright ◽

J. M. Ledingham

Keyword(s):

Blood Pressure ◽

Young People ◽

Sodium Excretion ◽

Mental Stress ◽

Significant Negative Correlation ◽

Potassium Excretion ◽

Excretion Ratio ◽

History Of ◽

Family History Of Hypertension ◽

Sodium And Potassium

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

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