scholarly journals Effect of dose and duration of reduction in dietary sodium on blood pressure levels: systematic review and meta-analysis of randomised trials

BMJ ◽  
2020 ◽  
pp. m315 ◽  
Author(s):  
Liping Huang ◽  
Kathy Trieu ◽  
Sohei Yoshimura ◽  
Bruce Neal ◽  
Mark Woodward ◽  
...  

AbstractObjectiveTo examine the dose-response relation between reduction in dietary sodium and blood pressure change and to explore the impact of intervention duration.DesignSystematic review and meta-analysis following PRISMA guidelines.Data sourcesOvid MEDLINE(R), EMBASE, and Cochrane Central Register of Controlled Trials (Wiley) and reference lists of relevant articles up to 21 January 2019.Inclusion criteriaRandomised trials comparing different levels of sodium intake undertaken among adult populations with estimates of intake made using 24 hour urinary sodium excretion.Data extraction and analysisTwo of three reviewers screened the records independently for eligibility. One reviewer extracted all data and the other two reviewed the data for accuracy. Reviewers performed random effects meta-analyses, subgroup analyses, and meta-regression.Results133 studies with 12 197 participants were included. The mean reductions (reduced sodium v usual sodium) of 24 hour urinary sodium, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were 130 mmol (95% confidence interval 115 to 145, P<0.001), 4.26 mm Hg (3.62 to 4.89, P<0.001), and 2.07 mm Hg (1.67 to 2.48, P<0.001), respectively. Each 50 mmol reduction in 24 hour sodium excretion was associated with a 1.10 mm Hg (0.66 to 1.54; P<0.001) reduction in SBP and a 0.33 mm Hg (0.04 to 0.63; P=0.03) reduction in DBP. Reductions in blood pressure were observed in diverse population subsets examined, including hypertensive and non-hypertensive individuals. For the same reduction in 24 hour urinary sodium there was greater SBP reduction in older people, non-white populations, and those with higher baseline SBP levels. In trials of less than 15 days’ duration, each 50 mmol reduction in 24 hour urinary sodium excretion was associated with a 1.05 mm Hg (0.40 to 1.70; P=0.002) SBP fall, less than half the effect observed in studies of longer duration (2.13 mm Hg; 0.85 to 3.40; P=0.002). Otherwise, there was no association between trial duration and SBP reduction.ConclusionsThe magnitude of blood pressure lowering achieved with sodium reduction showed a dose-response relation and was greater for older populations, non-white populations, and those with higher blood pressure. Short term studies underestimate the effect of sodium reduction on blood pressure.Systematic review registrationPROSPERO CRD42019140812.

Author(s):  
Abu Mohd Naser ◽  
Feng J. He ◽  
Mahbubur Rahman ◽  
Norm R.C. Campbell

We evaluated the relationship between estimated 24-hour urinary sodium excretion from the Kawasaki, Tanaka, and INTERSALT (International Study of Sodium, Potassium, and Blood Pressure) formulas and blood pressure (BP). We pooled 10 034 person-visit data from 3 cohort studies in Bangladesh that had measured 24-hour urine sodium (m-24hUNa), potassium, creatinine excretion, and BP. We used m-24hUNa, potassium, and creatinine where necessary, rather than spot urine values in the formulas. Bland-Altman plots were used to determine the bias associated with formula-estimated sodium relative to m-24hUNa. We compared the sodium excretion and BP relationships from m-24hUNa versus formula-estimated sodium excretions, using restricted cubic spline plots for adjusted multilevel linear models. All formulas overestimated 24-hour sodium at lower levels but underestimated 24-hour sodium at higher levels. There was a linear relationship between m-24hUNa excretion and systolic BP, while estimated sodium excretion from all 3 formulas had a J-shaped relationship with systolic BP. The relationships between urine sodium excretion and diastolic BP were more complex but were also altered by using formulas. All formulas had associations with BP when a sex-specific constant sodium concentration was inserted in place of measured sodium. Since we used the m-24hUNa, potassium, and creatinine concentrations in formulas, the J-shaped relationships are due to intrinsic problems in the formulas, not due to spot urine sampling. Formula-estimated 24-hour urine sodium excretion should not be used to examine the relationship between sodium excretion and BP since they alter the real associations.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiaofu Du ◽  
Le Fang ◽  
Jianwei Xu ◽  
Xiangyu Chen ◽  
Yamin Bai ◽  
...  

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.


2021 ◽  
pp. 1-42
Author(s):  
Yi-Jie Wang ◽  
Kuo-Lioug Chien ◽  
Hsiu-Ching Hsu ◽  
Hung-Ju Lin ◽  
Ta-Chen Su ◽  
...  

Abstract Urinary sodium excretion is a potential risk factor for cardiovascular diseases (CVD). However, the underlying biological mechanisms and effects of salt sensitivity are unclear. The purpose of this study was to characterize the relative contribution of biological factors to the sodium-CVD association. A total of 2112 participants were enrolled in this study. Structured questionnaires and blood and urine samples were obtained. Twenty-four-hour sodium excretion was estimated using a single overnight urine sample. Hypertension, metabolic syndrome, and overweight status were considered to indicate salt sensitivity. Cox proportional hazard models were used to investigate the effects of salt sensitivity on urinary sodium excretion and CVD risk. The traditional mediation approach was used to calculate the proportion of mediation. The mean age (standard deviation) of the 2112 participants was 54.5 (12.2) years, and they were followed up for a mean of 14.1 [8.1] years. Compared with those in the lowest quartile, the highest baseline urinary sodium excretion (>4.2g/24 hours) was associated with a 43% higher CVD risk (hazard ratio, 1.43; 95% confidence interval, 1.02-1.99). Participants with high urinary sodium excretion, hypertension, or metabolic syndrome had a significantly high risk of CVD. The carotid intima-media thickness had the largest mediating effect (accounting for 35% of the sodium-CVD association), followed by systolic blood pressure (33%), left ventricular mass (28%), and diastolic blood pressure (14%). Higher urinary sodium excretion increased the risk of CVD, which was explained largely by carotid media-thickness and systolic blood pressure.


Circulation ◽  
2021 ◽  
Vol 143 (16) ◽  
pp. 1542-1567 ◽  
Author(s):  
Tommaso Filippini ◽  
Marcella Malavolti ◽  
Paul K. Whelton ◽  
Androniki Naska ◽  
Nicola Orsini ◽  
...  

Background: The relationship between dietary sodium intake and blood pressure (BP) has been tested in clinical trials and nonexperimental human studies, indicating a direct association. The exact shape of the dose–response relationship has been difficult to assess in clinical trials because of the lack of random-effects dose–response statistical models that can include 2-arm comparisons. Methods: After performing a comprehensive literature search for experimental studies that investigated the BP effects of changes in dietary sodium intake, we conducted a dose–response meta-analysis using the new 1-stage cubic spline mixed-effects model. We included trials with at least 4 weeks of follow-up; 24-hour urinary sodium excretion measurements; sodium manipulation through dietary change or supplementation, or both; and measurements of systolic and diastolic BP at the beginning and end of treatment. Results: We identified 85 eligible trials with sodium intake ranging from 0.4 to 7.6 g/d and follow-up from 4 weeks to 36 months. The trials were conducted in participants with hypertension (n=65), without hypertension (n=11), or a combination (n=9). Overall, the pooled data were compatible with an approximately linear relationship between achieved sodium intake and mean systolic as well as diastolic BP, with no indication of a flattening of the curve at either the lowest or highest levels of sodium exposure. Results were similar for participants with or without hypertension, but the former group showed a steeper decrease in BP after sodium reduction. Intervention duration (≥12 weeks versus 4 to 11 weeks), type of study design (parallel or crossover), use of antihypertensive medication, and participants’ sex had little influence on the BP effects of sodium reduction. Additional analyses based on the BP effect of difference in sodium exposure between study arms at the end of the trial confirmed the results on the basis of achieved sodium intake. Conclusions: In this dose–response analysis of sodium reduction in clinical trials, we identified an approximately linear relationship between sodium intake and reduction in both systolic and diastolic BP across the entire range of dietary sodium exposure. Although this occurred independently of baseline BP, the effect of sodium reduction on level of BP was more pronounced in participants with a higher BP level.


2007 ◽  
Vol 293 (2) ◽  
pp. F586-F593 ◽  
Author(s):  
Xiao C. Li ◽  
L. Gabriel Navar ◽  
Yuan Shao ◽  
Jia L. Zhuo

We and others have previously shown that high levels of ANG II are accumulated in the rat kidney via a type 1 (AT1) receptor-mediated mechanism, but it is not known which AT1 receptor is involved in this process in rodents. We tested the hypothesis that AT1a receptor-deficient mice (Agtr1a−/−) are unable to accumulate ANG II intracellularly in the kidney because of the absence of AT1a receptor-mediated endocytosis. Adult male wild-type (Agtr1a+/+), heterozygous (Agtr1a+/−), and Agtr1a−/− were treated with vehicle, ANG II (40 ng/min ip via osmotic minipump), or ANG II plus the AT1 antagonist losartan (10 mg·kg−1·day−1 po) for 2 wk. In wild-type mice, ANG II induced hypertension (168 ± 4 vs. 113 ± 3 mmHg, P < 0.001), increased kidney-to-body weight ratio ( P < 0.01), caused pressure natriuresis ( P < 0.05), and elevated plasma and whole kidney ANG II levels ( P < 0.001). Concurrent administration of ANG II with losartan attenuated these responses to ANG II. In contrast, Agtr1a−/− mice had lower basal systolic pressures ( P < 0.001), smaller kidneys with much fewer AT1b receptors ( P < 0.001), higher basal 24-h urinary sodium excretion ( P < 0.01), as well as basal plasma and whole kidney ANG II levels ( P < 0.01). However, intracellular ANG II levels in the kidney were lower in Agtr1a−/− mice. In Agtr1a−/− mice, ANG II slightly increased systolic pressure ( P < 0.05) but had no effect on the kidney weight, urinary sodium excretion, and whole kidney ANG II levels. Losartan restored systolic pressure to basal levels and decreased whole kidney ANG II levels by ∼20% ( P < 0.05). These results demonstrate a predominant role of AT1a receptors in blood pressure regulation and in the renal responses to long-term ANG II administration, that AT1b receptors may play a limited role in blood pressure control and mediating intrarenal ANG II accumulation in the absence of AT1a receptors.


2020 ◽  
Vol 59 (5) ◽  
pp. 1815-1827 ◽  
Author(s):  
Seyed Mohammad Mousavi ◽  
Manije Darooghegi Mofrad ◽  
Israel Júnior Borges do Nascimento ◽  
Alireza Milajerdi ◽  
Tahereh Mokhtari ◽  
...  

1992 ◽  
Vol 262 (1) ◽  
pp. H149-H156 ◽  
Author(s):  
U. Palm ◽  
W. Boemke ◽  
H. W. Reinhardt

The existence of urinary excretion rhythms in dogs, which is a matter of controversy, was investigated under strictly controlled intake and environmental conditions. In seven conscious dogs, 14.5 mmol Na, 3.55 mmol K, and 91 ml H2O.kg body wt-1.24 h-1 were either administered with food at 8:30 A.M. or were continuously infused at 2 consecutive days. During these 3 days, automatized 20-min urine collections, mean arterial blood pressure (MABP), and heart rate (HR) recordings were performed without disturbing the dogs. Fundamental and partial periodicities, the noise component of urinary sodium excretion (UNaV), MABP, and HR were analyzed using a method derived from Fourier and Cosinor analysis. Oral intake (OI) leads to powerful 24-h periodicities in all dogs and seems to synchronize UNaV. UNaV on OI peaked between 1 and 3 P.M. Under the infusion regimen, signs of nonstationary rhythms and desynchronization predominated. UNaV under the infusion regimen could be separated into two components: a rather constant component continuously excreted and superimposed to this an oscillating component. No direct coupling between UNaV and MABP periodicities could be demonstrated. On OI, an increase in HR seems to advance the peak UNaV in the postprandial period. HR and MABP signals were both superimposed with noise. We conclude that UNaV rhythms are present in dogs. They are considerably more pronounced on OI.


Sign in / Sign up

Export Citation Format

Share Document