Twenty-four-hour urinary sodium and potassium excretion and associated factors in Japanese secondary school students

Okuda, Masayuki; Asakura, Keiko; Sasaki, Satoshi; Shinozaki, Keiko

doi:10.1038/hr.2016.24

Cited by 19 publications

(36 citation statements)

References 30 publications

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“…1, 2, 3, 4, 12 Errors due to under- or over-collection of 24-h urine specimens are lower for Na/K ratios compared with Na or K alone because the ratio is independent of urine volume. Methods for estimating 24-h urine Na and K excretions from casual urine specimens are dependent on urinary creatinine measurements, which may degrade if specimens are not well temperature-controlled; 15, 16, 17, 18, 19, 20 however, the ratio is independent of creatinine measurements. The measurement of urinary Na/K ratios could provide both onsite prompt feedback by portable handy devices 21 and good individual and population estimates of 24-h urinary Na/K ratios by using casual urine.…”

Section: Introductionmentioning

confidence: 99%

Diurnal variation of urinary sodium-to-potassium ratio in free-living Japanese individuals

et al. 2017

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High sodium-to-potassium ratios are associated with elevated blood pressure levels and an increased risk of cardiovascular diseases. We aimed to determine whether urinary sodium-to-potassium ratios fluctuate diurnally during the day to understand measured values of casual urinary sodium-to-potassium ratios. A total of 13,277 casual urine specimens were collected under free-living conditions from 122 Japanese normotensive and hypertensive individuals. Participants collected all casual urine samples in aliquot tubes, reported urine volumes and the time at each voiding for 10–22 days. Then, specimens were classified into hourly data. Diurnal patterns of urinary sodium-to-potassium ratios and urinary concentrations of sodium and potassium were evaluated. Overall mean values of hourly urinary sodium-to-potassium ratios were highest (4.1–5.0) in the early morning, lower (3.3–3.8) in the daytime and higher (4.0–4.4) toward evening hours. The mean urinary sodium and potassium concentrations were the lowest (90–110 and 24–32 mmol l−1, respectively) during the early morning and higher (110–140 and 35–43 mmol l−1, respectively) after mid-morning. Diurnal variability of potassium concentrations was larger than for sodium concentrations. Diurnal variations in urinary sodium-to-potassium ratios were comparable between normotensive and hypertensive individuals, between hypertensive individuals with and without antihypertensive medications, and among age and gender-specific subgroups. Overall mean hourly urinary sodium-to-potassium ratios fluctuated diurnally under free-living conditions and were higher during the morning and evening and lower during the daytime compared with 24-h urinary sodium-to-potassium ratios. Diurnal variation in urinary sodium-to-potassium ratios should be considered to understand actual daily dietary levels and avoid over- and under-estimation in clinical practice.

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Section: Introductionmentioning

confidence: 99%

Diurnal variation of urinary sodium-to-potassium ratio in free-living Japanese individuals

et al. 2017

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“…However, a preliminary report on male rats fed high fat and high salt (36%kcal and 4% NaCl) had less epididymal fat than high fat alone 70 . It is noteworthy that in Japan, where mean sodium intake is as high as 10.5g/day 13 , 71 , the lowest levels of obesity worldwide have been reported 72 . Moreover, our study suggests that efforts to reduce sodium intake in Japan may inadvertently be increasing adiposity in that nation 73 .…”

Section: Discussionmentioning

confidence: 99%

A high salt diet inhibits obesity and delays puberty in the female rat

et al. 2017

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Background/Objectives Processed foods are considered major contributors to the worldwide obesity epidemic. In addition to high sugar and fat contents, processed foods contain large amounts of salt. Due to correlations with rising adiposity, salt has recently been proposed to be obesogenic. This study investigated three hypotheses: i) high salt contributes to weight gain and adiposity in juvenile female rats, ii) puberty onset would be altered because salt is known to affect neuronal systems involved in activating the reproductive system, and iii) enhanced adiposity will act synergistically with salt to drive early puberty onset. Design Female weanling rats (post-natal day 21, n=105) were fed a low fat/low salt diet, low fat/high salt diet, high fat/low salt diet, or a high salt/high fat diet for 24 days. Metabolic measures, including weight gain, food intake, fecal output, activity, and temperature were recorded in subsets of animals. Results Body weight, retroperitoneal and perirenal fat pad weight, and adipocyte size were all lower in animals fed high fat/high salt compared to animals fed high fat alone. Leptin levels were reduced in high fat/high salt fed animals compared to high fat/low salt fed animals. Daily calorie intake was higher initially but declined with adjusted food intake and was not different among groups after 5 days. Osmolality and corticosterone were not different among groups. Fecal analysis showed excess fat excretion and a decreased digestive efficiency in animals fed high fat/low salt but not in animals fed high fat/high salt. Although respiratory exchange ratio was reduced by high dietary fat or salt, aerobic resting metabolic rate was not affected by diet. High salt delayed puberty onset, regardless of dietary fat content. Conclusions Salt delays puberty and prevents the obesogenic effect of a high fat diet. The reduced weight gain evident in high salt fed animals is not due to differences in food intake or digestive efficiency.

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“…P < 0.05 was considered as statistically significant. We additionally performed several sensitivity analyses with socioeconomic status, contraceptive use, aldosterone and potassium [18] included into multiple regression models, so to determine whether associations with the MBG/Na + ratio were confounded by these factors.…”

Section: Methodsmentioning

confidence: 99%

Marinobufagenin is related to elevated central and 24-h systolic blood pressures in young black women: the African-PREDICT Study

et al. 2018

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Marinobufagenin (MBG) is an endogenous steroidal α1-Na+K+-ATPase inhibitor. Because of its role in sodium handling, MBG has been associated with both antihypertensive and prohypertensive effects in normal physiology and pathology. MBG is positively associated with blood pressure in Dahl salt-sensitive rats exhibiting a similar hypertensive phenotype to black populations, characterized by impaired urinary Na+ excretion. However, clinical studies exploring blood pressure (BP)-related effects of MBG in black populations are scant. We determined whether the MBG/Na+ ratio (assessing the effectiveness of Na+ excretion resistance to MBG) is related to systolic BP (SBP) in young black men and women, compared to whites. We included 331 apparently healthy participants (20–30 years) (42.9% black, 43.8% men) on a habitual diet. We obtained 24-h and central SBP, and 24-h urinary Na+ and MBG levels. We found no ethnic differences in MBG, Na+ or MBG/Na+. MBG excretion correlated positively with Na+ excretion in all groups and to SBP in white men and black women (p ≤ 0.011). In black women only SBP related positively to MBG/Na+ in single and multi-variable adjusted regression models: central SBP (R2 = 0.26; ß = 0.28; p = 0.039), 24-h SBP (R2 = 0.46; ß = 0.30; p = 0.011), daytime (R2 = 0.38; ß = 0.28; p = 0.023) and nighttime SBP (R2 = 0.38; ß = 0.33; p = 0.009). In contrast, inverse associations of MBG/Na+ with nighttime SBP were evident in white women (r = −0.20; p = 0.038) but lost significance after multiple adjustments (R2 = 0.36; ß = −0.13; p = 0.12). We found independent positive associations of SBP with MBG/Na+ in black women. This data supports the concept that reduced MBG-mediated Na+ excretion can contribute to adverse hemodynamics.

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Twenty-four-hour urinary sodium and potassium excretion and associated factors in Japanese secondary school students

Cited by 19 publications

References 30 publications

Diurnal variation of urinary sodium-to-potassium ratio in free-living Japanese individuals

Diurnal variation of urinary sodium-to-potassium ratio in free-living Japanese individuals

A high salt diet inhibits obesity and delays puberty in the female rat

Marinobufagenin is related to elevated central and 24-h systolic blood pressures in young black women: the African-PREDICT Study

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