Association between sodium intake and change in uric acid, urine albumin excretion, and the risk of developing hypertension

Gene-environment interaction modifies the association between hyperinsulinemia and serum urate levels through SLC22A12

BACKGROUNDHyperinsulinemia and insulin resistance often accompany elevated serum urate levels (hyperuricemia), a highly heritable condition that triggers gout; however, the underlying mechanisms are unclear.METHODSWe evaluated the association between the index of hyperinsulinemia and the fractional excretion of urate (FEUA) in 162 outpatients. The underlying mechanisms were investigated through single-cell data analysis and kinase screening combined with cell culture experiments. In 377,358 participants of the UK Biobank (UKBB), we analyzed serum urate, hyperinsulinemia, and salt intake. We also examined gene-environment interactions using single nucleotide variants in SLC22A12, which encodes urate transporter 1 (URAT1).RESULTSThe index of hyperinsulinemia was inversely associated with FEUA independently of other covariates. Mechanistically, URAT1 cell-surface abundance and urate transport activity were regulated by URAT1-Thr408 phosphorylation, which was stimulated by hyperinsulinemia via AKT. Kinase screening and single-cell data analysis revealed that serum and glucocorticoid-regulated kinase 1 (SGK1), induced by high salt, activated the same pathway, increasing URAT1. Arg405 was essential for these kinases to phosphorylate URAT1-Thr408. In UKBB participants, hyperinsulinemia and high salt intake were independently associated with increased serum urate levels. We found that SLC22A12 expression quantitative trait locus (eQTL) rs475688 synergistically enhanced the positive association between serum urate and hyperinsulinemia.CONCLUSIONURAT1 mediates the association between hyperinsulinemia and hyperuricemia. Our data provide evidence for the role of gene-environment interactions in determining serum urate levels, paving the way for personalized management of hyperuricemia.FUNDINGACRO Research Grants of Teikyo University; Japan Society for the Promotion of Science; the Japanese Society of Gout and Uric & Nucleic Acids; Fuji Yakuhin; Nanken-Kyoten; Medical Research Center Initiative for High Depth Omics.

The Optimal Dietary Sodium or Chloride Level of Broilers Fed a Corn-Soybean Meal Diet from 22 to 42 Days of Age

The objective of this study was to assess the ideal dietary Na or Cl level for chickens from 22 to 42 d of age, utilizing a corn-soybean meal diet that maintains a 1:1 ratio of Na to Cl. At 22 d of age, a total of 288 male broilers of Arbor Acres were selected and randomly divided into one of six treatments. Each treatment contained eight replicates, with six chicks in each replicate. The control chicks were given a basic diet including 0.02% Na and 0.07% Cl without added Na or Cl, while the birds in other treatments were given diets containing different Na or Cl levels (0.13%, 0.19%, 0.25%, 0.31%, and 0.37%). With increasing dietary Na or Cl levels, linear (p < 0.0001) and quadratic (p < 0.0001) increases occurred in ADG, ADFI, and average daily water consumption, while F/G exhibited a linear (p < 0.0001) and quadratic (p < 0.0001) decrease from 22 to 42 d of age in broilers. Linear (p < 0.02) and quadratic increases (p < 0.03) were found in the heart indicator, serum Cl- concentrations, and blood Na+ and Cl- concentrations, whereas the kidney indicator, blood K+ concentrations, and serum K+, UA, and glucose (GLU) concentrations showed a linear (p < 0.04) and quadratic (p < 0.004) decrease with an increase in dietary Na or Cl levels. The excreta water content, liver indicator, and jejunal crypt depth also showed a linear increase (p < 0.02). The ideal levels of dietary Na or Cl were estimated to be 0.07% to 0.12%, based on the most suitable broken-line and asymptotic models (p ≤ 0.0002) using those sensitive indicators mentioned above. It was suggested that the suitable dietary Na or Cl level of 0.12% would adequately fulfill the Na or Cl metabolic demands of chickens from 22 to 42 d of age.

Association of Urinary Sodium, Potassium, and the Sodium-to-Potassium Ratio with Impaired Kidney Function Assessed with 24-H Urine Analysis

Background: Albuminuria and albumin excretion rate (AER) are important risk factors for chronic kidney disease (CKD) development. Despite the extensive evidence of the influence of sodium and potassium on cardiovascular health, the existing evidence regarding their impact on albuminuria and kidney disease is limited and inconsistent. Our study aimed to assess the correlation between urinary sodium and potassium excretion, and the sodium-to-potassium ratio (Na/K ratio) with impaired kidney function, particularly the AER and albuminuria. Materials and Methods: Data were collected from the Lithuanian NATRIJOD study. A total of 826 single 24-h urine samples from individuals aged 18 to 69 were collected and analyzed for their sodium and potassium levels, Na/K ratio, and AER. Albuminuria was defined as an AER exceeding 30 mg/24 h. Results: The participant mean age was 47.2 ± 12.1 years; 48.5% of the participants were male. The prevalence of albuminuria was 3%. Correlation analysis revealed a positive correlation between AER and urinary sodium excretion (rs = 0.21; p < 0.001) and urinary potassium excretion (rs = 0.28; p < 0.001). In univariate linear regression analysis, sodium and potassium excretion and the Na/K ratio were significant AER predictors with β coefficients of 0.028 (95% CI: 0.015; 0.041; p < 0.001), 0.040 (95% CI: 0.003; 0.077; p = 0.035), and 1.234 (95% CI: 0.210; 2.259; p = 0.018), respectively. In the multivariable model, only urinary sodium excretion remained significant, with a β coefficient of 0.028 (95% CI: 0.016; 0.041). Potential albuminuria predictive factors identified via univariate logistic regression included urinary sodium excretion (OR 1.00; 95% CI: 1:00; 1.01) and the Na/K ratio (OR 1.53; 95% CI: 1.11; 2.05). However, these factors became statistically insignificant in the multivariate model. Conclusions: Urinary sodium and potassium excretion and the Na/K ratio are significantly associated with kidney damage, considering the assessed 24-h albumin excretion rate and presence of albuminuria content.

Intake and food sources of sodium in the population residing in urban areas of Ecuador: results from ELANS study

BACKGROUND

In 2021, WHO notes that globally, 32% of annual deaths worldwide are due to cardiovascular causes, which have been attributed to excessive sodium intake, and therefore recommends a reduction in salt intake to less than 5 g/day. Ecuador does not have data on sodium consumption in the population. Hence, this study sought to determine the association between sodium consumption and sociodemographic variables in subjects living in urban areas of Ecuador.

OBJECTIVES

Determine the main dietary sources of sodium in subjects living in urban areas of the Coast and Highlands of Ecuador, and the association between sodium intake and sociodemographic variables such as: sex, region, marital status, socio-economic and educational level of this population.

METHODS

Sodium intake was studied in 800 subjects of both sexes aged 15 to 65 years living in urban areas in Ecuador, originating from the Latin American Nutrition and Health Study (ELANS) between 2014 and 2015. Data were obtained through two 24-hour recalls, and were accessed according to sex, region, age, marital status, socio-economic and educational levels.

RESULTS

The mean sodium intake was 4900 mg/day (SD ± 1188.32 mg/day), and both sexes exceeded the recommendations. Adjusting for energy intake, sodium consumption is higher in participants aged 50-65 years, from low socio-economic status and with basic education level. A positive relationship was found between sodium and energy intake. Around 48% of the sodium sources included the spices, condiments and herbs group. Within this group, salt itself constitutes 99% of sodium sources.

CONCLUSIONS

The Ecuadorian population consumes more than double the sodium recommendations, which vary according to gender and age. The first source of sodium is salt itself, which is part of spices and condiments food group. This data is important to formulate public health policies and interventions in Ecuador, especially in the population at risk.

Proteinuria Modifies the Relationship Between Urinary Sodium Excretion and Adverse Kidney Outcomes: Findings From KNOW-CKD

Introduction

High sodium intake is associated with increased proteinuria. Herein, we investigated whether proteinuria could modify the association between urinary sodium excretion and adverse kidney outcomes in patients with chronic kidney disease (CKD).

Methods

In this prospective observational cohort study, we included 967 participants with CKD stages G1 to G5 between 2011 and 2016, who measured 24-hour urinary sodium and protein excretion at baseline. The main predictors were urinary sodium and protein excretion levels. The primary outcome was CKD progression, which was defined as a ≥50% decline in the estimated glomerular filtration rate (eGFR) or the onset of kidney replacement therapy.

Results

During a median follow-up period of 4.1 years, the primary outcome events occurred in 287 participants (29.7%). There was a significant interaction between proteinuria and sodium excretion for the primary outcome (P = 0.006). In patients with proteinuria of <0.5 g/d, sodium excretion was not associated with the primary outcome. However, in patients with proteinuria of ≥0.5 g/d, a 1.0 g/d increase in sodium excretion was associated with a 29% higher risk of adverse kidney outcomes. Moreover, in patients with proteinuria of ≥0.5 g/d, the hazard ratios (HRs) (95% confidence intervals[CIs]) for sodium excretion of <3.4 and ≥3.4 g/d were 2.32 (1.50-3.58) and 5.71 (3.58-9.11), respectively, compared with HRs for patients with proteinuria of <0.5 g/d and sodium excretion of <3.4 g/d. In sensitivity analysis with 2 averaged values of sodium and protein excretion at baseline and third year, the results were similar.

Conclusion

Higher urinary sodium excretion was more strongly associated with an increased risk of adverse kidney outcomes in patients with higher proteinuria levels.

Association of 24-h urinary sodium excretion with microalbuminuria in a Chinese population

To assess the relationship of sodium, potassium and the ratio of sodium to potassium (Na/K) with albuminuria, a cross-sectional study was carried out in China in 2017. Sodium, potassium and albumin excretions were examined in a 24-h (h) urine sample collected from 1486 participants. Microalbuminuria was defined as 24-h urinary albumin excretion between 30 and 300 mg/24 h. The participants had an average age of 46.2 ± 14.1 years old, and 48.9% were men. The proportion of patients with microalbuminuria was 9.0%. As illustrated by the adjusted generalized linear mixed model, sodium concentration increased significantly with the increase in 24-h urinary albumin (β = 1.16, 95% confidence interval (CI) 0.38-1.93; P = 0.003). Multivariable-adjusted logistic regression analyses demonstrated that the odds ratio (OR) of microalbuminuria increased with the quartiles of sodium [OR = 2.20, 95% CI 1.26-3.84 (the maximum quartile vs. the minimum quartile), P_{for trend} = 0.006]. Potassium and the Na/K ratio did not have any association with outcome indicators. A high amount of sodium intake was potentially correlated with early renal function impairment.

Elevated Uric Acid Is Associated With New-Onset Atrial Fibrillation: Results From the Swedish AMORIS Cohort

Background The role of uric acid is gaining increasing importance in the evaluation of cardiovascular disease, but its relationship with atrial fibrillation (AF) is unclear. This study aims to investigate the association between uric acid levels and risk of new-onset AF. Methods and Results A total of 339 604 individuals 30 to 60 years of age and free from cardiovascular disease at baseline (1985-1996) in the Swedish AMORIS (Apolipoprotein-Mortality Risk) cohort were followed until December 31, 2019 for incident AF. Cox regression models were used to examine the association between uric acid and AF, adjusting for potential confounders and stratifying by incident cardiovascular disease. Over a mean follow-up of 25.9 years, 46 516 incident AF cases occurred. Compared with the lowest uric acid quartile, each of the upper 3 quartiles were associated with an increased risk of AF in a dose-response manner. Adjusted hazard ratios were 1.09 (95% CI, 1.06-1.12) for second quartile, 1.19 (95% CI, 1.16-1.23) for third quartile, and 1.45 (95% CI, 1.41-1.49) for fourth quartile. The association was similar among individuals with and without incident hypertension, diabetes, heart failure, or coronary heart disease. The dose-response pattern was further supported in a subsample of individuals with repeated measurements of uric acid. Conclusions Elevated uric acid was associated with an increased risk of AF, not only among people with cardiovascular disease and cardiovascular risk factors but also among those without. Future investigations are needed to examine whether lowering uric acid is relevant for AF prevention.

An optimal dietary sodium chloride supplemental level of broiler chicks fed a corn-soybean meal diet from 1 to 21 days of age

Sodium chloride (NaCl) is usually added to diets to meet the Na and Cl requirements of broilers in the Chinese poultry industry, but the optimal dietary NaCl supplemental level was not well-established. The present study was conducted to estimate the optimal dietary NaCl supplemental level of broilers fed a corn-soybean meal diet from 1 to 21 days of age. A total of 490, 1-day-old Arbor Acres male broilers were fed a NaCl-unsupplemented corn-soybean meal basal diet (control) and the basal diet supplemented with 0.10, 0.20, 0.30, 0.40, 0.50 or 0.60% NaCl for 21 days. Regression analysis was conducted to evaluate the optimal dietary NaCl level using the best fitted broken-line or asymptotic models. As dietary supplemental NaCl levels increased, average daily gain (ADG), average daily feed intake (ADFI), blood partial pressure of CO₂, total CO₂, base excess and anion gap, blood concentrations of HCO₃, Na and Cl, serum Na concentration, jejunal villus height (VH) and tibia ash content increased linearly and quadratically (P < 0.05), while feed/gain ratio, relative weights of heart, liver and kidney, blood K concentration, serum concentrations of K, uric acid and glucose, and osmotic pressure decreased linearly and quadratically (P < 0.05). The estimates of optimal dietary NaCl levels were 0.20-0.22% based on the best fitted broken-line or asymptotic models (P < 0.0001) of ADG, ADFI and feed/gain ratio, and 0.08-0.24% based on the best fitted broken-line or asymptotic models (P < 0.0001) of blood gas indices, serum parameters, jejunal VH, tibia ash content and organ indices. These results suggested that the optimal dietary NaCl supplemental level would be 0.24% for broilers fed the corn-soybean meal diet from 1 to 21 days of age, which is lower than the current dietary NaCl supplemental level (0.30%) in the Chinese broiler production.

Sodium Intake and Risk of Hypertension: A Systematic Review and Dose-Response Meta-analysis of Observational Cohort Studies

PURPOSE OF THE REVIEW

To assess the relationship between sodium intake and hypertension risk in cohort studies, based on a systematic review up to January 21, 2022, that also employed a dose-response meta-analysis.

RECENT FINDINGS

Dose-response analysis of available cohort studies (n = 11), using a dietary intake or urinary sodium excretion of 2 g/day as the reference category, showed an excess risk starting at 3 g/day. However, we found a linear relationship across the entire range of sodium exposure in an analysis restricted to studies that used 24 h urinary sodium excretion information and had a low risk of bias. This review confirms prior findings based on experimental studies and identified an almost linear relationship between sodium intake/excretion and hypertension risk in cohort studies, reinforcing the validity of recommendations to prevent cardiovascular disease through the reduction of sodium intake in both normotensive and hypertensive adults.

Association of eating out frequency and other factors with serum uric acid levels and hyperuricemia in Chinese population

PURPOSE

A significant shift in meal pattern with frequent eating out was closely associated with multiple chronic outcomes, but with limited evidence on hyperuricemia. We aimed to explore the associations between eating out and serum uric acid (SUA) as well as hyperuricemia.

METHODS

A total of 29,597 participants were recruited from the Henan Rural Cohort Study. A validated food frequency questionnaire (FFQ) was used to collect dietary data, including the frequency of eating out. Linear regression models were used to examine the association of eating-out frequency with SUA and BMI. Logistic regression and restricted cubic spline were performed to assess the association and dose-response relationship between eating-out frequency and hyperuricemia. The mediation effect of BMI between eating out and the risk of hyperuricemia was evaluated.

RESULTS

Eating out was significantly associated with higher SUA levels in the total population and males (P < 0.001). Multivariate-adjusted odds ratios (ORs) with 95% confidence interval (CIs) of hyperuricemia were 1.26 (1.09, 1.46) for the total population and 1.18 (1.00, 1.40) for males (≥ 7 times/week vs 0 time/week). A non-linear positive dose-response relationship between eating-out frequency and hyperuricemia was observed. Furthermore, BMI played a partial mediating role in the relationship between eating out frequency and hyperuricemia, which explained 30.7% in the total population and 44.8% in males.

CONCLUSION

Our findings indicated that eating out was associated with increased SUA levels and elevated hyperuricemia risk in rural China, especially in males. Moreover, the relationship was partly mediated by BMI.

CLINICAL TRIALS

ChiCTR-OOC-15006699 (2015-07-06).

Clinic and ambulatory blood pressure in relation to the interaction between plasma advanced glycation end products and sodium dietary intake and renal handling

Advanced glycation end product (AGE) clearance may cause renal tubular injuries, such as changes in sodium reabsorption. We hypothesize that AGEs interact with sodium metabolism to influence blood pressure (BP). The study participants were outpatients who were suspected of having hypertension but had not been treated with antihypertensive medication. Clinic and ambulatory blood pressures were measured at baseline (n = 989) and during follow-up (median, 4.4 years, n = 293). Plasma AGE concentrations were measured by enzyme-linked immunosorbent assay. Twenty-four-hour urine was collected for measurements of creatinine, sodium and lithium. In a cross-sectional analysis (n = 989), subjects in the top quintile versus quintiles 1-4 of plasma AGE concentration had significantly (P ≤ 0.004) lower fractional excretion of lithium (18.3% vs. 21.6%) and fractional distal reabsorption rate of sodium (95.0% vs. 95.8%) but similar BP (P ≥ 0.25). However, there was an interaction between plasma AGE concentration and urinary sodium excretion in relation to diastolic BP (P ≤ 0.058). Only in participants with low urinary sodium chloride excretion (≤6 grams/day, n = 189), clinic (84.3 vs. 80.2 mmHg), 24-h (83.9 vs. 80.4 mmHg), daytime (87.8 vs. 84.8 mmHg) and nighttime (75.1 vs. 72.1 mmHg) diastolic BP at baseline were higher (P ≤ 0.05) in the top quintile than in quintiles 1-4 of plasma AGE concentration. In the longitudinal study (n = 383), similar trends were observed, with significant (P ≤ 0.05) differences in the increment in daytime diastolic BP (6.8 vs. -1.7 mmHg) and incidence of ambulatory and treated hypertension (hazard ratio 3.73) during follow-up. In conclusion, AGEs were associated with high BP, probably via enhanced proximal sodium handling and on low dietary sodium intake.

Association of Sodium, Potassium and Sodium-to-Potassium Ratio with Urine Albumin Excretion among the General Chinese Population

Mixed evidence was published regarding the association of sodium, potassium and sodium-to-potassium ratio (Na/K ratio) with renal function impairment. This study was conducted to further explore the relationship between sodium, potassium, NA/K ratio and kidney function in the general adult Chinese population. We performed a cross-sectional analysis using the baseline data from the Action on Salt China (ASC) study. 5185 eligible general adult participants from the baseline investigation of the ASC study were included in this analysis. Sodium, potassium and albumin excretion were examined from 24-h urine collection. Albuminuria was defined as albumin excretion rate (AER) greater than or equal to 30 mg/24-h. Mixed linear regression models, adjusted for confounders, were fitted to analyze the association between sodium, potassium and Na/K ratio, and natural log transformed AER. Mixed effects logistic regression models were performed to analyze the odds ratio of albuminuria at each quintile of sodium, potassium and Na/K ratio. The mean age of the participants was 49.5 ± 12.8 years, and 48.2% were male. The proportion of albuminuria was 7.5%.The adjusted mixed linear models indicated that sodium and Na/K ratio was positively associated with natural log transformed AER (Sodium: β = 0.069, 95%CI [0.050, 0.087], p < 0.001; Na/K ratio: β = 0.026, 95%CI [0.012, 0.040], p < 0.001). Mixed effects logistic regression models showed that the odds of albuminuria significantly increased with the quintiles of sodium (p < 0.001) and Na/K ratio (p = 0.001). No significant association was found between potassium and the outcome indicators. Higher sodium intake and higher Na/K ratio are associated with early renal function impairment, while potassium intake was not associated with kidney function measured by albumin excretion.

Association between ultrapocessed food and chronic kidney disease

The modern diet is closely linked to the consumption of processed foods, causing an increase in the intake of salt, simple sugars, phosphorus and added potassium. This excess intake is associated with an increased risk of obesity, diabetes, hypertension and chronic kidney disease (CKD). CKD, which according to data from the ENRICA study affects 15% of the population, magnifies its impact due to the higher prevalence of diabetes and hypertension and due to limitations in the management of sodium and phosphorus. The intake of these products far exceeds the established recommendations, assuming 72% of total sodium, 25%-35% of phosphorus, 12%-18% of potassium and exceeding 10% of the caloric intake in simple sugars. Measures are necessary to reduce their contribution through nutritional advice, labeling review, education campaigns on healthy habits, fees and institutional actions that involve food safety agencies, industry, distribution and scientific societies.

Dietary sodium and cardiovascular morbidity/mortality: a brief commentary on the 'J-shape hypothesis'

The last decade, a growing number of evidence support J-shape or inverse - instead of positive linear -- associations between dietary sodium intake and cardiovascular morbidity/mortality. A careful evaluation of these studies leads to the following observations: less accurate methods for dietary sodium assessment are usually used; most studies included high-risk participants, enhancing the possibility of a 'reverse causality' phenomenon. However, these limitations do not explain all the findings. Few carefully designed randomized clinical trials comparing different levels of sodium intake that address the issue of the optimal and safe range exist; therefore, current guidelines recommend a higher cut-off instead of a safe range of intake. Given the demonstrated harmful effects of very low sodium diets leading to subclinical vascular damage in animal studies, the 'J-shape hypothesis' cannot yet be either neglected or verified. There is a great need of well-designed general population-based prospective randomized clinical trials to address the issue.

Association between ultrapocessed food and chronic kidney disease

The modern diet is closely linked to the consumption of processed foods, causing an increase in the intake of salt, simple sugars, phosphorus and added potassium. This excess intake is associated with an increased risk of obesity, diabetes, hypertension and chronic kidney disease (CKD). CKD, which according to data from the ENRICA study affects 15% of the population, magnifies its impact due to the higher prevalence of diabetes and hypertension and due to limitations in the management of sodium and phosphorus. The intake of these products far exceeds the established recommendations, assuming 72% of total sodium, 25-35% of phosphorus, 12-18% of potassium and exceeding 10% of the caloric intake in simple sugars. Measures are necessary to reduce their contribution through nutritional advice, labeling review, education campaigns on healthy habits, fees and institutional actions that involve food safety agencies, industry, distribution and scientific societies.

Estimation of salt intake assessed by 24-h urinary sodium level among adults speaking different dialects from the Chaoshan region of southern China

OBJECTIVE

Dietary salt intake may vary depending on different lifestyles. We aimed to estimate the different salt intakes and evaluate the knowledge and self-awareness about salt among people speaking the Teochew, Teochew-Hakka and Hakka dialects in the Chaoshan region of southern China.

DESIGN

The study followed a cluster sampling of residents in Chaoshan region. General characteristics, lifestyles, health status as well as knowledge and self-awareness related to salt intake were investigated using a questionnaire. Anthropometric variables as well as Na and K excretion in a 24-h urine collection were measured.

SETTING

Chaoshan region of China.

PARTICIPANTS

Four hundred fifteen adults who spoke only one of these three dialects.

RESULTS

The salt intake of adults who spoke the Teochew, Teochew-Hakka and Hakka dialects was 7·19 (interquartile range (IQR) 5·29-10·17), 9·03 (IQR 6·62-11·54) and 10·12 (IQR 7·61-12·82) g/d, respectively, with significant differences between Teochew and Teochew-Hakka speakers and between Teochew and Hakka speakers (both P < 0·05). The Na:K ratio for adults who spoke the three dialects was 3·00 (IQR 2·00-4·11), 3·50 (IQR 2·64-4·82) and 4·52 (IQR 3·35-5·97), respectively, and differed significantly among the groups (all P < 0·05). Multiple linear regression analysis showed increased Na:K ratio associated with hypertension (β = 0·71, P = 0·043) in Hakka speakers. Knowledge and self-awareness about salt intake were poor in this population.

CONCLUSIONS

Salt intake was closely related to lifestyles and was higher than the upper limit (5 g/d) recommended by the WHO in adults of Chaoshan, especially those speaking the Hakka dialect.

Modifiable Lifestyle Factors for Primary Prevention of CKD: A Systematic Review and Meta-Analysis

BACKGROUND

Despite increasing incidence of CKD, no evidence-based lifestyle recommendations for CKD primary prevention apparently exist.

METHODS

To evaluate the consistency of evidence associating modifiable lifestyle factors and CKD incidence, we searched MEDLINE, Embase, CINAHL, and references from eligible studies from database inception through June 2019. We included cohort studies of adults without CKD at baseline that reported lifestyle exposures (diet, physical activity, alcohol consumption, and tobacco smoking). The primary outcome was incident CKD (eGFR<60 ml/min per 1.73 m²). Secondary outcomes included other CKD surrogate measures (RRT, GFR decline, and albuminuria).

RESULTS

We identified 104 studies of 2,755,719 participants with generally a low risk of bias. Higher dietary potassium intake associated with significantly decreased odds of CKD (odds ratio [OR], 0.78; 95% confidence interval [95% CI], 0.65 to 0.94), as did higher vegetable intake (OR, 0.79; 95% CI, 0.70 to 0.90); higher salt intake associated with significantly increased odds of CKD (OR, 1.21; 95% CI, 1.06 to 1.38). Being physically active versus sedentary associated with lower odds of CKD (OR, 0.82; 95% CI, 0.69 to 0.98). Current and former smokers had significantly increased odds of CKD compared with never smokers (OR, 1.18; 95% CI, 1.10 to 1.27). Compared with no consumption, moderate consumption of alcohol associated with reduced risk of CKD (relative risk, 0.86; 95% CI, 0.79 to 0.93). These associations were consistent, but evidence was predominantly of low to very low certainty. Results for secondary outcomes were consistent with the primary finding.

CONCLUSIONS

These findings identify modifiable lifestyle factors that consistently predict the incidence of CKD in the community and may inform both public health recommendations and clinical practice.

Association between Dietary Patterns and Kidney Function Parameters in Adults with Metabolic Syndrome: A Cross-Sectional Study

This study explored the association between dietary patterns and kidney function parameters in adults with metabolic syndrome in Taiwan. This cross-sectional study was undertaken in 56,476 adults from the health screening centers in Taiwan from 2001 to 2010. Dietary intake and dietary patterns were assessed using a food frequency questionnaire and principal component analysis, respectively. Blood urea nitrogen (BUN), creatinine, estimated glomerular filtration rate (eGFR), and uric acid were measured as clinical parameters of kidney function. Multivariate linear regression was conducted to explore the relationship between dietary patterns and kidney function parameters. After adjusting for confounders, the highest tertiles of the processed food–sweets dietary pattern and the meat–seafood–eggs dietary pattern were associated with increased BUN, creatinine, and uric acid but decreased eGFR (all adjusted p < 0.05). Meanwhile, the highest tertiles of the veggie–fruit–grains dietary pattern and the milk–dairy dietary pattern were associated with decreased BUN, creatinine, and uric acid but increased eGFR (all adjusted p < 0.05). A processed food–sweets dietary pattern or a meat–seafood–eggs dietary pattern is associated with worse kidney function parameters in adults with metabolic syndrome. In contrast, a veggie–fruit–grains dietary pattern or a milk–dairy dietary pattern is associated with better kidney function parameters.

Ambulatory blood pressure in relation to interaction between dietary sodium intake and serum uric acid in the young

PURPOSE

We hypothesise that dietary sodium intake interacts with serum uric acid to influence blood pressure (BP) in children and adolescents. In the present study, we investigated ambulatory BP in relation to hyperuricaemia, dietary sodium intake and their interaction in children and adolescents with hypertension.

MATERIALS AND METHODS

A total of 616 study participants were 10-24 years old and had primary hypertension diagnosed after admission in a specialised inpatient ward. Ambulatory BP monitoring was performed during hospitalisation. 24-h urine was collected for measurements of electrolytes. Hyperuricaemia was defined as a serum uric acid of ≥327.25 μmol/L in patients <18 years old and of ≥420 and ≥360 μmol/L, respectively, in male and female patients ≥18 years old.

RESULTS

In adjusted analyses, patients with hyperuricaemia (n = 283), compared with those with normal serum uric acid, had similar 24-h systolic BP (131.7 mmHg, p = 0.54) and a significantly (p ≤ 0.005) lower 24-h diastolic BP (77.5 vs. 80.9 mmHg) and higher 24-h pulse pressure (54.2 vs. 51.7 mmHg). In similar adjusted analyses, 24-h ambulatory pulse pressure, but not systolic/diastolic BP (p ≥ 0.12), significantly differed across the quartile distributions of urinary sodium excretion (p for trend ≤ 0.04). Further adjusted analyses showed significant (p ≤ 0.04) interaction between serum uric acid and urinary sodium excretion in relation to 24-h systolic BP. In patients with hyperuricaemia (p = 0.04), but not those with normal serum uric acid (p = 0.13), 24-h systolic BP was significantly associated with urinary sodium excretion, with a 6.5 ± 2.1 mmHg difference between quartiles 4 and 1. Similar results were observed for daytime and night-time BP and pulse pressure.

CONCLUSIONS

Both hyperuricaemia and higher dietary sodium intake were associated with higher pulse pressure, and their interaction further heightened systolic BP.

Past Sodium Intake, Contemporary Sodium Intake, and Cardiometabolic Health in Southwest Coastal Bangladesh

Background We compared the relationship of past and contemporary sodium (Na) intake with cardiometabolic biomarkers. Methods and Results A total of 1191 participants' data from a randomized controlled trial in coastal Bangladesh were analyzed. Participants provided 24-hour urine Na (24UNa) data for 5 monthly visits. Their fasting blood glucose, total cholesterol, triglycerides, high-density lipoprotein, blood pressure, and 24-hour urine protein were measured at the fifth visit. Participants' mean 24UNa over the first 4 visits was the past Na, and 24UNa of the fifth visit was the contemporary Na intake. We estimated the prevalence ratios of elevated cardiometabolic biomarkers and metabolic syndrome across 24UNa tertiles by multilevel logistic regression using participant-, household-, and community-level random intercepts. Models were adjusted for age, sex, body mass index, smoking, physical activity, alcohol consumption, sleep hours, religion, and household wealth. Compared with participants in tertile 1 of past urine Na, those in tertile 3 had 1.46 (95% CI, 1.08-1.99) times higher prevalence of prediabetes or diabetes mellitus, 5.49 (95% CI, 2.73-11.01) times higher prevalence of large waist circumference, and 1.60 (95% CI, 1.04-2.46) times higher prevalence of metabolic syndrome. Compared with participants in tertile 1 of contemporary urine Na, those in tertile 3 had 1.93 (95% CI, 1.24-3.00) times higher prevalence of prediabetes or diabetes mellitus, 3.14 (95% CI, 1.45-6.83) times higher prevalence of proteinuria, and 2.23 (95% CI, 1.34-3.71) times higher prevalence of large waist circumference. Conclusions Both past and contemporary Na intakes were associated with higher cardiometabolic disease risk.

Frequency of alcohol drinking modifies the association between salt intake and albuminuria: a 1-year observational study

Albuminuria is an important risk factor for end-stage kidney disease and cardiovascular mortality. This 1-year observational study aimed to assess the effect modification of alcohol drinking on the association between salt intake and albuminuria. Overall, 448 employees at a pharmaceutical company in Japan who underwent annual health checkups in both 2017 and 2018 were evaluated. The main exposure of interest was drinking frequency at their first checkups categorized as rarely, occasionally, and daily. To assess the association between the changes in salt intake and albuminuria, the differences in salt intake estimated from single-spot urine specimens and the urinary albumin-to-creatinine ratio (UACR) between 2017 and 2018 were calculated for each subject. A multivariable-adjusted linear regression model showed a significant association between ∆salt intake and ∆Log UACR (per 1 g/day of ∆salt intake, adjusted ß 0.16 [95% confidence interval 0.14, 0.19]) and an effect modification between drinking frequency and ∆salt intake (P for interaction = 0.088). The association between ∆salt intake and ∆Log UACR was enhanced by drinking frequency in a dose-dependent manner (per 1 g/day of ∆salt intake, adjusted ß 0.13 [0.06, 0.19], 0.16 [0.12, 0.20], and 0.20 [0.13, 0.27] in rare, occasional, and daily drinkers, respectively). In conclusion, the results of the present study indicated that salt-induced albuminuria was enhanced in subjects with higher drinking frequency, suggesting that salt restriction may have a stronger renoprotective effect in subjects with higher drinking frequency.

The effect of uric acid and urinary sodium excretion on prehypertension: a nationwide population-based study

Background

This study examined the effect of serum uric acid (SUA) level and urinary sodium excretion on blood pressure as well as their combined effect on prehypertension in a Korean population.

Method

Data from the 7th Korea National Health and Nutrition Examination Survey for adults (≥ 19 years of age) were used. The participants were classified into two groups, normotension and prehypertension, according to the JNC-7 definition. Logistic regression was carried out and adjusted for traditionally regarded confounders of blood pressure. All analyses considered a complex sampling design. A multivariate analysis was performed on subgroups defined according to their SUA level and urinary sodium excretion.

Results

The 4200 participants were divided into normotension (n = 2646) and prehypertension (n = 1554) groups. In the univariate analysis, patient age, male sex, concurrent comorbidity (diabetes mellitus, cardiovascular disease, stroke, dyslipidemia, and chronic kidney disease), uric acid, and urinary sodium excretion were associated with prehypertension. After adjusting for baseline covariates, both the SUA level and urinary sodium excretion were significant predictors of incident prehypertension (SUA, per 1 mg/dL increase, odds ratio [OR] 1.216, 95% confidence interval [95% CI] 1.131–1.309; urinary sodium excretion, per 1 g/day increase, OR 1.067, 95% CI 1.019–1.117). Additionally, simultaneously higher tertiles of SUA and urinary sodium excretion resulted in higher ORs for prehypertension.

Conclusion

Increased SUA is a significant risk marker for the development of prehypertension in normotensives. Simultaneously high SUA and urinary sodium excretion amplified the effect on the development of prehypertension. Our findings suggest that lowering SUA levels and reducing sodium intake will contribute to preventing hypertension.

Changes in Urinary Microalbumin Levels after Correction of Hyperuricemia in Patients with Gout: An Observational Cohort Study

Background

Gout is commonly associated with metabolic syndrome. Strong association between the serum uric acid level and microalbuminuria has also been observed in various studies.

Aim

To observe the change in urinary microalbumin after urate-lowering treatment in patients with gout and microalbuminuria. Methodology. A prospective, observational study was conducted at a tertiary-level rheumatic center (NCRD) in Kathmandu, Nepal. Adults diagnosed with gout using the 2015 ACR/EULAR criteria and microalbuminuria were enrolled in the study after obtaining informed consent. Sociodemographic profile and clinical history were recorded at baseline. Serum uric acid levels, spot urinary microalbumin (MAU) excretion, blood sugar, lipid profile, and blood pressure were measured at baseline, 3-month follow-up, and 6-month follow-up. A paired t-test was used to compare the change in mean MAU after treatment.

Results

A total of 778 patients diagnosed with gout were screened for microalbuminuria. Among them, 114 (14.6%) had urinary microalbumin levels of >30.0 mg/L during presentation. Mean MAU level among those with microalbuminuria was 132.4 ± 124.6 mg/L. Thirty-five patients had concomitant HTN and were put on ARBs (20 mg of telmisartan). All received 40 mg of febuxostat. In patients with ARBs, MAU reduced significantly after 3 months of treatment with ARBs. Reduction in MAU in those without ARBs was seen after the 6-month follow-up, and the change was statistically significant.

Conclusions

There is significant reduction in MAU after the use of urate-lowering drugs in patients with gout.

Separating the effects of 24-hour urinary chloride and sodium excretion on blood pressure and risk of hypertension: Results from PREVEND

Objective

Research into dietary factors associated with hypertension has focused on the sodium component of salt. However, chloride has distinct physiological effects that may surpass the effect of sodium on blood pressure. This study aims to separate the specific effects of chloride and sodium intake on blood pressure.

Methods

We studied 5673 participants from the Prevention of Renal and Vascular End-Stage Disease(PREVEND) study. Urinary chloride(uCl) and sodium(uNa) were measured in two 24-hour collections. We used generalized-linear-regression to evaluate the relation of uCl and uNa with baseline blood pressure and Cox-proportional-hazards-analysis to assess the association with hypertension. Multicollinearity was assessed with Ridge regression.

Results

Baseline 24-hour uCl was 135±39mmol and uNa was 144±54mmol. The correlation between uCl and uNa was high (Pearson’s r = 0.96). UCl and uNa had similar non-significant positive and linear associations with blood pressure. In 3515 normotensive patients, 1021 patients developed hypertension during a median follow-up of 7.4 years. UCl and uNa had a comparable but non-significant J-shaped effect on the risk of hypertension. Adding both uCl and uNa to the same model produced instability, demonstrated by Ridge coefficients that converged or changed sign. The single index of uNa minus uCl showed a non-significant higher risk of hypertension of 2% per 10mmol/24-hour difference (HR1.02, 95%CI 0.98–1.06).

Conclusion

UCl and uNa had similar positive but non-significant associations with blood pressure and risk of hypertension and their effects could not be disentangled. Hence, the alleged adverse effects of high salt intake could be due to sodium, chloride or both. This encourages further study into the effect of chloride in order to complement dietary recommendations currently focused on sodium alone.

Association of uric acid in serum and urine with subclinical renal damage: Hanzhong Adolescent Hypertension Study

BACKGROUND AND OBJECTIVES

The aim of the study was to examine the associations of uric acid (UA) in blood and urine with subclinical renal damage (SRD) and its progression in a Chinese cohort.

METHODS

1) 2342 participants from our previously established cohort who were followed up in 2017 were included. Cross-sectional analysis was used to examine the relationships between serum and urinary UA and the risk of SRD. 2) A total of 266 participants were recruited from the same cohort in 2013, and followed up in 2017. Longitudinal analysis was used to determine the relationships of serum and urinary UA with progression of SRD, which was defined as urinary albumin-to-creatinine ratio (uACR) progression or estimated glomerular filtration rate (eGFR) decline.

RESULTS

In cross-sectional analysis, higher levels of uACR were associated with higher levels of serum uric acid (SUA) and urinary uric acid/creatinine ratio (uUA/Cre). Lower eGFR was associated with higher levels of SUA and fractional excretion of uric acid (FEUA) but lower uUA/Cre levels in all subjects. In addition, the multivariate-adjusted odds ratios for SRD compared with non-SRD were 3.574 (2.255-5.664) for uUA/Cre. Increasing uUA/Cre levels were associated with higher risk of SRD. In longitudinal analysis, 4-year changes of uUA/Cre and SUA were significantly associated with eGFR decline.

CONCLUSIONS

This study suggested that urinary UA excretion was significantly associated with the risk of SRD in Chinese adults. Furthermore, 4-year changes of serum and urinary UA were associated with SRD progression. These findings suggest that UA, especially urinary UA, may be used as a simple, noninvasive marker for early detection of decreased renal function in otherwise healthy subjects.

Non-Communicable Diseases on the Rise in Sub-Saharan Africa, the Underappreciated Threat of a Dual Disease Burden

In sub-Saharan Africa, the burden of non-communicable diseases (NCDs) remains under appreciated, but emerging evidence suggests it to be substantial. NCDs such as arterial hypertension, heart diseases, diabetes mellitus and chronic kidney diseases are especially relevant, and put additional strain on the already challenged health systems in this region. Moreover, NCDs appear to be associated with higher mortality and morbidity rates and are more common in younger population groups, in people from sub-Saharan Africa when compared to more developed countries. In this review, we summarize the current literature on the burden of NCDs in sub-Saharan Africa, and highlight the clinical implications of the most relevant etiologies, i.e. arterial hypertension, heart diseases, diabetes mellitus and chronic kidney diseases.

Dietary reference values for sodium

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) derived dietary reference values (DRVs) for sodium. Evidence from balance studies on sodium and on the relationship between sodium intake and health outcomes, in particular cardiovascular disease (CVD)-related endpoints and bone health, was reviewed. The data were not sufficient to enable an average requirement (AR) or population reference intake (PRI) to be derived. However, by integrating the available evidence and associated uncertainties, the Panel considers that a sodium intake of 2.0 g/day represents a level of sodium for which there is sufficient confidence in a reduced risk of CVD in the general adult population. In addition, a sodium intake of 2.0 g/day is likely to allow most of the general adult population to maintain sodium balance. Therefore, the Panel considers that 2.0 g sodium/day is a safe and adequate intake for the general EU population of adults. The same value applies to pregnant and lactating women. Sodium intakes that are considered safe and adequate for children are extrapolated from the value for adults, adjusting for their respective energy requirement and including a growth factor, and are as follows: 1.1 g/day for children aged 1-3 years, 1.3 g/day for children aged 4-6 years, 1.7 g/day for children aged 7-10 years and 2.0 g/day for children aged 11-17 years, respectively. For infants aged 7-11 months, an Adequate Intake (AI) of 0.2 g/day is proposed based on upwards extrapolation of the estimated sodium intake in exclusively breast-fed infants aged 0-6 months.

Impact of serum uric acid on incident hypertension in a worksite population of Japanese men

OBJECTIVE

Higher levels of serum uric acid are associated with an increased risk of cardiovascular diseases, which may be confounded by comorbidities. We investigated the effects of serum uric acid on the risk of hypertension in Japanese men at a worksite.

METHODS

We evaluated a total of 2335 Japanese male workers without hypertension who ranged in age from 18 to 64 years at a worksite in 2009. These men were followed for 6 years from 2009 to 2015.

RESULTS

During the follow-up period, 380 individuals developed hypertension. The odds ratio for the incident hypertension was estimated according to quartiles of serum uric acid levels of 5.1 or less, 5.2-5.8, 5.9-6.6, and at least 6.7 mg/dl. The multivariable-adjusted risk of incident hypertension was significantly higher in the highest serum uric acid quartile than in the lowest: odds ratio 1.00 (reference) for the lowest quartile, 1.34 (0.91-1.97) for the second quartile, 1.42 (0.97-2.06) for the third quartile, and 1.65 (1.14-2.40) for the highest quartile. In stratified analyses, the association between serum uric acid and incident hypertension was significant in the patients of aged below 45 years and without comorbidities, namely diabetes and low levels of high-density lipoprotein-cholesterol.

CONCLUSIONS

Serum uric acid levels were associated with the future incidence of hypertension, and the association was observed in the younger individuals, those without diabetes, and those with preserved high-density lipoprotein cholesterol levels in a worksite population of Japanese men.

Sex differences in cardiac and renal responses to a high salt diet in Sprague-Dawley rats

High dietary salt intake is an important risk factor for cardiovascular and renal diseases. However, sexual disparity exists in the response of target organs to high salt diet (HSD). To determine how sex affects cardiac and renal functions' response to HSD, 20 weanling Sprague-Dawley rats (10 males and 10 females) were divided into 4 groups of 5 rats each. The rats were fed a normal diet (0.3% NaCl) or HSD (8% NaCl) for 12 weeks. Fluid balance (FB) was determined from 24 hrs water intake and voided urine. Blood pressure (BP) was measured via arterial cannulation under anesthesia (25% w/v urethane and 1% w/v α-chloralose; 5 ml/kg, i.p). Serum levels of troponin I, aminotransaminases, creatinine, urea, uric acid and electrolytes as well as urinary concentration of albumin, creatinine, and electrolytes were measured using appropriate assay kits. Values are presented as mean ± S.E.M, compared by two-way ANOVA and Bonferroni post Hoc test. In the male rat, HSD significantly increased BP, serum: Troponin I, LDH and sodium (p < 0.05), urinary: albumin, sodium, potassium and FB (p < 0.05). In the female rat, HSD increased BP, serum: troponin I, LDH, sodium and creatinine clearance (p < 0.05), urinary: albumin, sodium and potassium (p < 0.01). However, HSD increased more, the BP, serum: Troponin I, LDH, urinary albumin and FB in male rats, while HSD increased urinary sodium more in female rats. Basal values in male vs. female of serum LDH and urinary albumin were significantly different. Thus, sex plays an important role in the response of the heart and kidney to salt stress.

Changes in blood pressure associated with lead, manganese, and selenium in a Bangladeshi cohort

BACKGROUND

Heavy metal contamination is widespread in Bangladesh. Previous studies have observed lead increases blood pressure over time. However, the role of other metal contaminants and essential micronutrients, which could also adversely affect blood pressure or act as protective factors, is understudied.

OBJECTIVES

We therefore evaluated the associations of lead, manganese, and selenium with blood and pulse pressure trajectories.

METHODS

We prospectively followed placebo-assigned participants nested within a randomized trial for the prevention of arsenic-related skin cancer (n = 255). Blood lead, manganese, and selenium were measured at baseline; blood pressure was measured at baseline and at 3 biennial follow-up examinations. Mixed-effect linear regression models were used to estimate associations with average annual changes in systolic, diastolic, and pulse pressure.

RESULTS

In models simultaneously adjusted for baseline blood lead, manganese, and selenium concentrations in addition to other potential confounders, lead was linearly associated with increases in systolic blood pressure, but not with diastolic blood pressure or pulse pressure. A non-linear association was observed for manganese, such that mid-range concentrations were associated with decreases in systolic, diastolic, and pulse pressure. Baseline selenium concentrations in the highest quartile were also associated with longitudinal decreases in both systolic and diastolic blood pressure, while null associations were observed with pulse pressure. In exploratory analyses, the combination of mid-range manganese and high selenium concentrations completely offset lead-associated increases in blood and pulse pressure.

CONCLUSIONS

The results indicate a direct, linear association of lead exposure with systolic blood pressure, and manganese and selenium exposures within certain ranges may have a blood pressure-lowering effect in this population.

Plasma xanthine oxidase activity is related to increased sodium and left ventricular hypertrophy in resistant hypertension

BACKGROUND

The extra-renal effects of aldosterone on left ventricular (LV) structure and function are exacerbated by increased dietary sodium in persons with hypertension. Previous studies demonstrated endothelial dysfunction and increased oxidative stress with high salt diet in normotensive salt-resistant subjects. We hypothesized that increased xanthine oxidase (XO), a product of endothelial cells, is related to 24-h urinary sodium and to LV hypertrophy and function in patients with resistant hypertension (RHTN).

METHODS

The study group included persons with RHTN (n = 91), defined as a blood pressure > 140/90 mmHg on ≥ 3 medications at pharmacologically effective doses. Plasma XO activity and 24-h urine were collected, and cardiac magnetic resonance imaging (MRI) was performed to assess LV function and morphology. Sixty-seven normotensive persons on no cardiovascular medications served as controls. A subset of RHTN (n = 19) received spironolactone without salt restriction for six months with follow-up XO activity measurements and MRI analyses.

RESULTS

XO activity was increased two-fold in RHTN vs. normal and was positively correlated with LV mass, LV diastolic function, and 24-h urinary sodium. In RHTN patients receiving spironolactone without salt restriction, LV mass decreased, but LV diastolic function and XO activity did not improve. Baseline urinary sodium was positively associated with rate of change of LV mass to volume ratio and the LV E/A ratio.

CONCLUSIONS

These results demonstrate a potential role of endothelium-derived oxidative stress and excess dietary salt in the pathophysiology of LV hypertrophy and diastolic dysfunction in persons with RHTN unaffected by the addition of spironolactone.

High Serum Uric Acid is Highly Associated with a Reduced Left Ventricular Ejection Fraction Rather than Increased Plasma B-type Natriuretic Peptide in Patients with Cardiovascular Diseases

High serum uric acid (UA) has been reported to be associated with left ventricular (LV) dysfunction; however, the relationship between UA and plasma B-type natriuretic peptide (BNP), a sensitive biomarker of heart failure, is still unclear. This study investigated their relationship to provide an accurate assessment of high UA. The study patients consisted of 3,077 subjects who underwent cardiac catheterization because of various cardiovascular disorders. Since the explanatory factors of multiple regression analysis were mostly confounding with each other, subgroup analysis was performed by quartering the study population using the respective risk factors and by covariance structure analysis. This analysis revealed that UA was almost always well associated with a reduced LV ejection fraction (LVEF), but generally not with BNP. UA was significantly associated with BNP in lean aged females, but not in obese adolescent males, although LVEF was significantly reduced in response to a high UA in both groups. A high UA is a direct risk factor for cardiac dysfunction from the perspective of BNP; however, augmentation of BNP in response to a high UA would likely be restricted among obese adolescent males. On the other hand, the observed LV systolic dysfunction, such as LVEF, reflects a high UA on an almost constant basis.

Sodium excretion and associated factors in urine samples of African descendants in Alcântara, Brazil: a population based study

In most countries, salt intake has been excessive and constitutes one of the main risk factors for disease development, especially hypertension. Factors such as age, gender, sedentary lifestyle, smoking, African descent, obesity, dietary habits and family history of hypertension may be associated with high blood pressure. Studies show a positive association between the excretion of sodium and increased blood pressure. We evaluated the urinary excretion of sodium and associated factors in isolated urine samples of African descendants from remaining Quilombos. We performed a cross-sectional, population-based study with 1162 African descendants living in remaining quilombos in Alcântara, Maranhão, Brazil. Demographic, nutritional, clinical and laboratory data were analyzed. Urinary sodium excretion was estimated using the Kawasaki equation. A multivariate linear regression model was used to identify the variables related to sodium excretion. The average age was 37.6 ± 11.8 years and 51.2% were women. The prevalence of hypertension was 21.3%. The average urinary excretion of sodium was high, especially among the hypertensive (217.9 ± 90.1 vs. 199.2 ± 83.0 mmol/d; p = .002). After an adjusted analysis, only the waist circumference (odds ratios (OR) = 1.16; confidence intervals(CI)95%: 1.03-1.30), triglyceride (OR = 1.13; CI95%: 1.05-1.22), systolic blood pressure (OR = 1.19; CI95%: 1.08-1.32) and Chronic Kidney Disease Epidemiology (CKD-EPI;OR = 1.24; CI95%: 1.15-1.35) remained related to urinary sodium excretion. African descendants had a high rate of sodium excretion, especially among those who had hypertension. Abdominal adiposity, triglyceride and systolic blood pressure levels and renal function by CKD-EPI equation were associated to urinary sodium excretion.

Dietary Sodium Intake and Serum Uric Acid: A Mini-Review

The aim of the present review is to summarize recent studies on the relationship between dietary sodium intake and serum uric acid concentration. In short-term dietary sodium intervention studies, including a recent further analysis of a previously published trial, high dietary sodium intake (200 mmol/day), compared with a low sodium diet (20-60 mmol/day), resulted in a significant reduction in serum uric acid, being approximately 20-60 μmol/L. This finding, though consistent across short-term studies, is in contradiction to the long-term observational evidence on the relationship between dietary sodium intake and serum uric acid. Indeed, in a population-based prospective study, high dietary sodium intake was associated with a higher serum uric acid concentration. If serum uric acid would be followed up, several currently ongoing long-term randomized dietary sodium intervention studies may shed some light on how dietary sodium intake interacts with serum uric acid in the development of hypertension.

Association between urinary sodium excretion and uric acid, and its interaction on the risk of prehypertension among Chinese young adults

High uric acid (UA) level and high salt intake are reportedly associated with cardiovascular disease. This study investigated the association between UA and urinary sodium excretion, as well as its interaction on the risk of prehypertension. A total of 1869 participants without hypertension were recruited from a previously established cohort in Shaanxi Province, China. The participants were classified as normotensive or prehypertensive on the basis of their blood pressure. Increasing quartiles of sodium excretion were associated with high urinary UA/creatinine levels in prehypertensive participants. Estimated sodium excretion positively correlated with urinary UA/creatinine excretions in the prehypertensive group. In addition, the multivariate-adjusted odds ratios for prehypertension compared with normotension were 1.68 (1.27–2.22) for sodium excretion and 1.71 (1.21–2.42) for serum UA. Increasing sodium excretion and serum UA were associated with higher risk of prehypertension. Compared with the lowest quartiles, the highest sodium excretion and serum UA quartiles entailed 3.48 times greater risk of prehypertension. Sodium excretion is associated with urinary UA excretion in prehypertensive participants. The present study shows that high levels of salt intake and serum UA simultaneously are associated with a higher risk of prehypertension.

Urinary excretion of uric acid is negatively associated with albuminuria in patients with chronic kidney disease: a cross-sectional study

Background

Increasing evidence has shown that albuminuria is related to serum uric acid. Little is known about whether this association may be interrelated via renal handling of uric acid. Therefore, we aim to study urinary uric acid excretion and its association with albuminuria in patients with chronic kidney disease (CKD).

Methods

A cross-sectional study of 200 Chinese CKD patients recruited from department of nephrology of Huadong hospital was conducted. Levels of 24 h urinary excretion of uric acid (24-h Uur), fractional excretion of uric acid (FEur) and uric acid clearance rate (Cur) according to gender, CKD stages, hypertension and albuminuria status were compared by a multivariate analysis. Pearson and Spearman correlation and multiple regression analyses were used to study the correlation of 24-h Uur, FEur and Cur with urinary albumin to creatinine ratio (UACR).

Results

The multivariate analysis showed that 24-h Uur and Cur were lower and FEur was higher in the hypertension group, stage 3–5 CKD and macro-albuminuria group (UACR> 30 mg/mmol) than those in the normotensive group, stage 1 CKD group and the normo-albuminuria group (UACR< 3 mg/mmol) (all P < 0.05). Moreover, males had higher 24-h Uur and lower FEur than females (both P < 0.05). Multiple linear regression analysis showed that UACR was negatively associated with 24-h Uur and Cur (P = 0.021, P = 0.007, respectively), but not with FEur (P = 0.759), after adjusting for multiple confounding factors.

Conclusions

Our findings suggested that urinary excretion of uric acid is negatively associated with albuminuria in patients with CKD. This phenomenon may help to explain the association between albuminuria and serum uric acid.

Dietary Sodium and Other Nutrient Intakes among Patients Undergoing Hemodialysis in New Zealand

This study describes baseline intakes of sodium and other nutrients in a multi-ethnic sample of hemodialysis patients in New Zealand participating in the SoLID Trial between May/2013 to May/2016. Baseline 3-day weighed food record collections were analyzed using Foodworks 8 Professional food composition database, supplemented by other sources of nutrient information. Intakes of dietary sodium and other nutrients were compared with relevant guidelines and clinical recommendations. Eighty-five participants completed a 3-day weighed food record. The mean (SD) sodium intake was 2502 (957) mg/day at and more than half of the participants exceeded recommended intake levels. Sodium intake was positively associated with energy intake. Only 5% of participants met the recommended calorie density; nine percent of participants ate the recommended minimum of 1.2 g/kg of protein per day; 68% of participants were consuming inadequate fiber at baseline. A high proportion of dialysis patients in SoLID Trial did not meet current renal-specific dietary recommendations. The data show excess sodium intake. It is also evident that there was poor adherence to dietary guidelines for a range of other nutrients. A total diet approach is needed to lower sodium intake and improve total diet quality among hemodialysis patients in New Zealand.

Hypertension Control in Adults With CKD in China: Baseline Results From the Chinese Cohort Study of Chronic Kidney Disease (C-STRIDE)

BACKGROUND

Hypertension contributes to increased morbidity and mortality in the chronic kidney disease (CKD) population. Studies on blood pressure control in CKD patients in China are limited. In this study, we aimed to describe the status of blood pressure control in Chinese CKD patients based on the first national prospective CKD cohort data.

METHODS

A subgroup of Chinese Cohort Study of Chronic Kidney Disease participants with hypertension at baseline was included in the present study. Uncontrolled blood pressure was defined as systolic blood pressure ≥140 mm Hg and/or diastolic blood pressure ≥90 mm Hg. Defined daily doses (DDDs) are used as a standard measurement of drug utilization in this population. Factors associated with uncontrolled blood pressure were analyzed using multivariable logistic regression.

RESULTS

There were 2,251 hypertensive CKD subjects among 2,873 predialysis CKD participants. The awareness, treatment, and control rates of hypertension were 80.7%, 95.6%, and 57.1%, respectively. Factors independently associated with uncontrolled blood pressure were overweight, obesity, albuminuria, decreased estimated glomerular filtration rate (eGFR), and diabetes. Over 50% of study subjects were prescribed 2 or more antihypertensive medications and only 7% were prescribed diuretics. Uncontrolled hypertensive patients were prescribed less antihypertensive medication than controlled hypertensives (DDD 1.3 [1.0-2.3] vs. 2.0 [1.0-3.1], P < 0.001).

CONCLUSIONS

Hypertension control was suboptimal among hypertensive CKD patients in China, especially among those overweight or with obesity, albuminuria, lower eGFR, and diabetes. Patients with uncontrolled hypertension should undergo treatment regimen evaluation to select the appropriate dosage and type of antihypertensive medications.

Effects of serum uric acid on blood-pressure lowering treatment

If hyperuricemia is an independent risk factor in blood-pressure control, urate-lowering therapy should be used to reduce cardiovascular risk. It may also act as a prognostic marker of other abnormalities. This review presents current evidence on the relationship between hyperuricemia and hypertension.

Prognostic Significance of Spot Urine Na/K for Longitudinal Changes in Blood Pressure and Renal Function: The Nagahama Study

BACKGROUND

Urinary sodium-to-potassium ratio (Na/K) represents a simple measure of sodium load and has been reported to be associated with blood pressure (BP) levels in a cross-sectional setting even with spot measurements. The aim of the present large-scale cohort study is to determine prognostic significance of spot urine Na/K for longitudinal changes in BP levels and renal function.

METHODS

The present study population consisted of 7,063 individuals from the general population. Clinical parameters were measured at baseline and at a follow-up interval of 5 years.

RESULTS

Mean systolic BP was slightly increased during the follow-up period (overall, 124 ± 17 to 125 ± 18 mm Hg; nontreated participants, 119 ± 15 to 122 ± 17 mm Hg). Although, the urinary Na/K demonstrated a linear association with BP in a cross-sectional analysis (P < 0.001), analysis of repeated measured BP values identified baseline Na/K * time interaction, i.e., an intraindividual effect, as an inverse determinant (F = 76.9, P < 0.001) independently of hypertension status and fasting conditions possibly due to regression to the mean of temporary high baseline Na/K values at baseline. Spot urine Na/K values were found to be positively associated with renal function in a cross-sectional analysis (P < 0.001). Although baseline Na/K * time interaction showed inverse associated with renal functional decline (F = 85.8, P < 0.001), this inverse association might not represent physiological relationship in likewise fashion with the analysis for BP.

CONCLUSIONS

Spot urine Na/K may have limited utility as a prognostic marker of longitudinal BP change, as well as renal functional decline.

Diet-independent relevance of serum uric acid for blood pressure in a representative population sample

A direct relationship between serum uric acid and blood pressure (BP) has been reported, but the possible confounding impact of diet on this association is unclear. The authors performed a cross-sectional analysis in the representative German Health Interview and Examination Survey for Adults (n=6788, aged 18-79 years). In adjusted regression models considering dietary factors, each 1-mg/dL higher uric acid value was associated with a 1.10-mm Hg (P=.0002) and a 0.60-mm Hg (P=.04) higher systolic BP among participants younger than 50 years and participants 50 years and older, respectively. For diastolic BP, uric acid was a significant predictor (β=0.71 mm Hg, P=.0001) among participants younger than 50 years and for participants 50 years and older without antihypertensive treatment. Adjusted odds ratios of hypertension for participants with hyperuricemia were broadly similar in younger (odds ratio, 1.71; P=.02) and older (odds ratio, 1.81; P=.0003) participants. Uric acid is a significant predictor of systolic BP and hypertension prevalence in the general adult population in Germany independently of several known dietary BP influences.

Close linkage between serum uric acid and cardiac dysfunction in patients with ischemic heart disease according to covariance structure analysis

High serum uric acid (UA) level has been assumed to be a risk factor for left ventricular (LV) dysfunction; however, the precise relationship between these conditions has not been fully examined because many confounding factors are associated with UA level. We herein examined the precise relationship by proposing structural equation models. The study population consisted of 1432 cases with ischemic heart disease who underwent cardiac catheterization. Multiple regression analyses and covariance structure analyses were performed to elucidate the cause-and-effect relationship between UA level and LV ejection fraction (LVEF). A path model exploring the factors contributing to LVEF showed that high UA was a significant cause of reduced LVEF (P = 0.004), independent of other significant factors. The degree of atherosclerosis, as estimated by the number of diseased coronary vessels, was significantly affected by high UA (P = 0.005); and the number of diseased coronary vessels subsequently led to reduced LVEF (P < 0.001). Another path model exploring the factors contributing to UA level showed that LVEF was a significant cause of high UA (P = 0.001), while other risk factors were also independent contributing factors. This study clearly demonstrated that there was a close link between high UA and LV dysfunction, which was represented by possible cause-and-effect relationship.

Myocardial extracellular volume fraction quantified by cardiovascular magnetic resonance is increased in hypertension and associated with left ventricular remodeling

OBJECTIVES

To determine whether extracellular volume fraction (ECV) quantification by cardiac magnetic resonance (CMR) can demonstrate left ventricle (LV) abnormalities and relationship between ECV and LV remodeling in hypertension (HTN) patients METHODS: ECV quantification was prospectively performed in 134 consecutive HTN patients and 97 healthy subjects. Individual and regional ECV were compared to the regions on late gadolinium enhancement (LGE) images. Statistical analysis of the relationship between LV global functional parameters and ECV was carried out using Pearson's correlation, Student's t test and multiple regressions.

RESULTS

In the HTN group, 70.1% (94/134) were LGE negative and 29.9% (40/134) LGE positive. The mean ECV after adjusting for age, sex, BMI, diabetes, smoking and dyslipidaemia in healthy controls and LGE-negative patients were 26.9 ± 2.67% and 28.5 ± 2.9% (p < 0.001), respectively. The differences in ECV reached statistical significance among the regions of LGE, LGE-Peri, LGE remote and the normal area between the control and LGE-positive subgroup (all p < 0.05). Global ECV significantly correlated with LVEF (r = -0.466, p < 0 .001) and LV hypertrophy (r = 0.667, p < 0.001).

CONCLUSIONS

ECV can identify LV abnormalities at an early stage in HTN patients without LGE. These abnormalities may reflect an increase in diffuse myocardial fibrosis and are associated with LV remodeling.

KEY POINTS

• Diffuse myocardial fibrosis may develop in hypertensive cardiomyopathy before conventional MRI detectable LGE. • ECV can identify myocardial fibrosis at an early stage in hypertensive patients. • Elevated ECV is associated with decreased LV global function and LV remodeling in hypertension.

Opposing effects of sodium intake on uric acid and blood pressure and their causal implication

Reducing uric acid is hypothesized to lower blood pressure, although evidence is inconsistent. In this ancillary of the DASH-Sodium trial, we examined whether sodium-induced changes in serum uric acid (SUA) were associated with changes in blood pressure. One hundred and three adults with prestage or stage 1 hypertension were randomly assigned to receive either the DASH diet or a control diet (typical of the average American diet) and were fed each of the three sodium levels (low, medium, and high) for 30 days in random order. Body weight was kept constant. SUA was measured at baseline and following each feeding period. Participants were 55% women and 75% black. Mean age was 52 (SD, 10) years, and mean SUA at baseline was 5.0 (SD, 1.3) mg/dL. Increasing sodium intake from low to high reduced SUA (-0.4 mg/dL; P < .001) but increased systolic (4.3 mm Hg; P < .001) and diastolic blood pressure (2.3 mm Hg; P < .001). Furthermore, changes in SUA were independent of changes in systolic (P = .15) and diastolic (P = .63) blood pressure, regardless of baseline blood pressure, baseline SUA, and randomized diet, as well as sodium sensitivity. Although both SUA and blood pressure were influenced by sodium, a common environmental factor, their effects were in opposite directions and were unrelated to each other. These findings do not support a consistent causal relationship between SUA and BP.

Effect of Soy Sauce on Serum Uric Acid Levels in Hyperuricemic Rats and Identification of Flazin as a Potent Xanthine Oxidase Inhibitor

This is the first report on the ability of soy sauce to effectively reduce the serum uric acid levels and xanthine oxidase (XOD) activities of hyperuricemic rats. Soy sauce was partitioned sequentially into ethyl acetate and water fractions. The ethyl acetate fraction with strong XOD inhibition effect was purified further. On the basis of xanthine oxidase inhibitory (XOI) activity-guided purification, nine compounds including 3,4-dihydroxy ethyl cinnamate, diisobutyl terephthalate, harman, daidzein, flazin, catechol, thymine, genistein, and uracil were obtained. It was the first time that 3,4-dihydroxy ethyl cinnamate and diisobutyl terephthalate had been identified from soy sauce. Flazin with hydroxymethyl furan ketone group at C-1 and carboxyl at C-3 exhibited the strongest XOI activity (IC50 = 0.51 ± 0.05 mM). According to fluorescence quenching and molecular docking experiments, flazin could enter into the catalytic center of XOD to interact with Lys1045, Gln1194, and Arg912 mainly by hydrophobic forces and hydrogen bonds. Flazin, catechol, and genistein not only were potent XOD inhibitors but also held certain antioxidant activities. According to ADME (absorption, distribution, metabolism, and excretion) simulation in silico, flazin had good oral bioavailability in vivo.

Influence of Salt Intake on Association of Blood Uric Acid with Hypertension and Related Cardiovascular Risk

BACKGROUND

A relationship of blood uric acid (UA) with hypertension and cardiovascular risk is under debate thus salt intake is hypothesized to contribute to such associations.

METHODS

In this cross-sectional study, stratified cluster random sampling elicited a sample of 1805 Kazakhs with 92.4% compliance. Hypertension and moderate-or-high total cardiovascular risk (mTCR) were defined according to guidelines. Sodium intake was assessed by urinary sodium excretion. Prevalence ratios (PRs) were used to express associations of UA with hypertension and mTCR.

RESULTS

In the highest tertile of sodium intake in women, the adjusted PRs (95% confidence intervals) of low to high quartiles compared with the lowest quartile of UA, were 1.22(0.78-1.91), 1.18(0.75-1.85), and 1.65(1.09-2.51) for hypertension and 1.19(0.74-1.90), 1.39(0.91-2.11), and 1.65(1.10-2.47) for mTCR (P for trend <0.05). However, these findings were not shown for other sodium intake levels. There were similar results in men. PRs markedly increased with a concomitant increase in UA and sodium intake and there was a significant interaction (P = 0.010) for mTCR with PRs of 1.69(1.10-2.60) for men and 3.70(2.09-6.52) for women in those with the highest compared with the lowest quartile of UA and tertile of sodium intake. Similar findings were shown for hypertension.

CONCLUSIONS

This study implied that a high salt intake may enhance the associations of UA with hypertension and cardiovascular risk.