Sodium Intake and Cause-Specific Mortality Among Predominantly Low-Income Black and White US Residents.

IMPORTANCE: Epidemiologic evidence regarding the outcomes of dietary sodium intake on mortality remains limited for low-income individuals, particularly Black people. OBJECTIVE: To investigate the associations of excessive dietary sodium with all-cause and cause-specific mortality among predominantly low-income Black and White Americans. DESIGN, SETTING, AND PARTICIPANTS: This cohort study included participants aged 40 to 79 years from the Southern Community Cohort Study who were recruited at Community Health Centers in 12 southeastern states from 2002 to 2009. Analyses were conducted between March 2022 and June 2023. EXPOSURES: Dietary sodium intake was assessed using a validated food frequency questionnaire at baseline. MAIN OUTCOMES AND MEASURES: Multivariable-adjusted Cox regression was used to estimate hazard ratios (HRs) and 95% CIs for mortality outcomes (all-cause, cardiovascular disease [CVD], coronary heart disease [CHD], stroke, heart failure, cancer, and other) associated with sodium intake. Nonlinear associations and population-attributable risk (PAR) of the mortality burden associated with excess sodium were further assessed. RESULTS: Among the 64 329 participants, 46 185 (71.8%) were Black, 18 144 (28.2%) were White, and 39 155 (60.9%) were female. The mean (SD) age at study enrollment was 51.3 (8.6) years for Black participants and 53.3 (9.3) years for White counterparts. Mean (SD) dietary sodium intake was 4512 (2632) mg/d in Black individuals and 4041 (2227) mg/d in White individuals; 37 482 Black individuals (81.2%) and 14 431 White individuals (79.5%) exceeded the current dietary recommendations of 2300 mg/d. During a median (IQR) follow-up of 13.8 (11.3-15.8) years, 17 811 deaths were documented, including 5701 from CVD. After adjustment for potential confounders, in Black individuals, HRs per 1000-mg increase in daily sodium intake were 1.07 (95% CI, 1.03-1.10) and 1.08 (95% CI, 1.02-1.14) for deaths from total CVD and CHD, respectively; while in White individuals, the corresponding HRs were 1.08 (95% CI, 1.02-1.14) and 1.13 (95% CI, 1.03-1.23). No significant associations were found for cancer mortality. PAR estimates suggest that sodium intake above the recommended threshold may account for 10% of total CVD, 13% of CHD, and 30% of heart failure deaths in this low-income southern population. CONCLUSIONS AND RELEVANCE: In this cohort study of 64 329 low-income Americans, nearly 80% of study participants consumed sodium exceeding the current recommended daily amount, which was associated with 10% to 30% of CVD mortality. Public health programs targeted to reduce sodium intake among this underserved population may be beneficial.

Sex-specific associations between sodium and potassium intake and overall and cause-specific mortality: a large prospective U.S. cohort study, systematic review, and updated meta-analysis of cohort studies.

BACKGROUND: The impact of sodium intake on cardiovascular disease (CVD) health and mortality has been studied for decades, including the well-established association with blood pressure. However, non-linear patterns, dose-response associations, and sex differences in the relationship between sodium and potassium intakes and overall and cause-specific mortality remain to be elucidated and a comprehensive examination is lacking. Our study objective was to determine whether intake of sodium and potassium and the sodium-potassium ratio are associated with overall and cause-specific mortality in men and women. METHODS: We conducted a prospective analysis of 237,036 men and 179,068 women in the National Institutes of Health-AARP Diet and Health Study. Multivariable-adjusted Cox proportional hazard regression models were utilized to calculate hazard ratios. A systematic review and meta-analysis of cohort studies was also conducted. RESULTS: During 6,009,748 person-years of follow-up, there were 77,614 deaths, 49,297 among men and 28,317 among women. Adjusting for other risk factors, we found a significant positive association between higher sodium intake (≥ 2,000 mg/d) and increased overall and CVD mortality (overall mortality, fifth versus lowest quintile, men and women HRs = 1.06 and 1.10, Pnonlinearity < 0.0001; CVD mortality, fifth versus lowest quintile, HRs = 1.07 and 1.21, Pnonlinearity = 0.0002 and 0.01). Higher potassium intake and a lower sodium-potassium ratio were associated with a reduced mortality, with women showing stronger associations (overall mortality, fifth versus lowest quintile, HRs for potassium = 0.96 and 0.82, and HRs for the sodium-potassium ratio = 1.09 and 1.23, for men and women, respectively; Pnonlinearity < 0.05 and both P for interaction ≤ 0.0006). The overall mortality associations with intake of sodium, potassium and the sodium-potassium ratio were generally similar across population risk factor subgroups with the exception that the inverse potassium-mortality association was stronger in men with lower body mass index or fruit consumption (Pinteraction < 0.0004). The updated meta-analysis of cohort studies based on 42 risk estimates, 2,085,904 participants, and 80,085 CVD events yielded very similar results (highest versus lowest sodium categories, pooled relative risk for CVD events = 1.13, 95% CI: 1.06-1.20; Pnonlinearity < 0.001). CONCLUSIONS: Our study demonstrates significant positive associations between daily sodium intake (within the range of sodium intake between 2,000 and 7,500 mg/d), the sodium-potassium ratio, and risk of CVD and overall mortality, with women having stronger sodium-potassium ratio-mortality associations than men, and with the meta-analysis providing compelling support for the CVD associations. These data may suggest decreasing sodium intake and increasing potassium intake as means to improve health and longevity, and our data pointing to a sex difference in the potassium-mortality and sodium-potassium ratio-mortality relationships provide additional evidence relevant to current dietary guidelines for the general adult population. SYSTEMATIC REVIEW REGISTRATION: PROSPERO Identifier: CRD42022331618.

Spatiotemporal trends in the burden of aortic aneurysms caused by high sodium intake from 1990 to 2019: A global, regional, and national analysis.

BACKGROUND AND AIMS: This study, drawing on Global Burden of Disease (GBD) data, examines spatiotemporal trends in mortality and disability-adjusted life years (DALYs) linked to aortic aneurysm (AA) from high sodium intake. The aim is a comprehensive analysis globally, regionally, and nationally spanning 1990 to 2019. METHODS AND RESULTS: Quantifying AA deaths and DALYs due to high sodium intake, incorporating age-standardized mortality rate (ASMR) and age-standardized DALYs rate (ASDR), revealed a global surge. Deaths rose by 86.09 %, DALYs by 74.02 % from 1990 to 2019. EAPC for ASMR and ASDR displayed negative trends (-0.72 and -0.77). High/middle-high Socio-demographic Index (SDI) regions bore higher burdens than lower SDI regions. Males consistently had higher burdens across SDI regions, with both genders showing a slight downward trend. Age-wise, AA deaths and DALYs rose with age, followed by decline. A positive correlation existed between SDI and global burden, inversely related to EAPC for ASMR and ASDR. CONCLUSION: AA burden from high sodium intake is pronounced in high SDI regions, necessitating targeted interventions. The global data highlights a significant increase in AA deaths and DALYs due to high sodium intake, urging prompt and effective control measures.

Sex-Specific Association between Sodium Intake Estimated by 24-Hour Urinary Sodium Excretion and Nonalcoholic Fatty Liver Disease: The Community-Based Prospective Cohort Study.

Evidence for the association between high sodium intake and the onset of nonalcoholic fatty liver disease (NAFLD) is insufficient. This study examined the sex-specific association between sodium intake and the risk of NAFLD. This study included 2582 adults (aged 40-69 years; 1011 males and 1571 females). The total sodium excreted over 24 h was estimated from spot urine specimens using Tanaka's equation. Based on these estimates, participants were categorized into three groups according to their 24-h urinary sodium excretion levels: lowest (T1), middle (T2), and highest (T3). In addition, the participants were divided into non-NAFLD (≤36) and NAFLD (>36) groups based on the hepatic steatosis index. During the follow-up period (14 years), NAFLD was observed in 551 participants. The estimated 24-h urinary sodium excretion levels were positively associated with the incidence of NAFLD in all subjects. Upon sex stratification, females in the T2 and T3 groups exhibited adjusted hazard ratios of 1.35 and 1.51, respectively, compared with the T1 group. However, a significant relationship was not observed in males. High intake of sodium, especially among females, may be an important factor contributing to the development of NAFLD. Individuals with high sodium intake should be appropriately counselled and monitored for the risk of NAFLD.

The contribution of sodium reduction and potassium increase to the blood pressure lowering observed in the Salt Substitute and Stroke Study.

The Salt Substitute and Stroke Study (SSaSS) demonstrated significant reductions in systolic blood pressure (SBP), and the risk of stroke, major cardiovascular events and total mortality with the use of potassium-enriched salt. The contribution of sodium reduction versus potassium increase to these effects is unknown. We identified four different data sources describing the association between sodium reduction, potassium supplementation and change in SBP. We then fitted a series of models to estimate the SBP reductions expected for the differences in sodium and potassium intake in SSaSS, derived from 24-h urine collections. The proportions of the SBP reduction separately attributable to sodium reduction and potassium supplementation were calculated. The observed SBP reduction in SSaSS was -3.3 mmHg with a corresponding mean 15.2 mmol reduction in 24-h sodium excretion and a mean 20.6 mmol increase in 24-h potassium excretion. Assuming 90% of dietary sodium intake and 70% of dietary potassium intake were excreted through urine, the models projected falls in SBP of between -1.67 (95% confidence interval: -4.06 to +0.73) mmHg and -5.33 (95% confidence interval: -8.58 to -2.08) mmHg. The estimated proportional contribution of sodium reduction to the SBP fall ranged between 12 and 39% for the different models fitted. Sensitivity analyses assuming different proportional urinary excretion of dietary sodium and potassium intake showed similar results. In every model, the majority of the SBP lowering effect in SSaSS was estimated to be attributable to the increase in dietary potassium rather than the fall in dietary sodium.

Assessing the effects of tempol on renal fibrosis, inflammation, and oxidative stress in a high-salt diet combined with 5/6 nephrectomy rat model: utilizing oxidized albumin as a biomarker.

BACKGROUND: Oxidative stress has been implicated in the pathogenesis of chronic kidney disease (CKD), prompting the exploration of antioxidants as a potential therapeutic avenue for mitigating disease progression. This study aims to investigate the beneficial impact of Tempol on the progression of CKD in a rat model utilizing oxidized albumin as a biomarker. METHODS: After four weeks of treatment, metabolic parameters, including body weight, left ventricle residual weight, kidney weight, urine volume, and water and food intake, were measured. Systolic blood pressure, urinary protein, oxidized albumin level, serum creatinine (Scr), blood urea nitrogen (BUN), 8-OHdG, TGF-ß1, and micro-albumin were also assessed. Renal fibrosis was evaluated through histological and biochemical assays. P65-NF-κB was quantified using an immunofluorescence test, while Smad3, P65-NF-κB, and Collagen I were measured using western blot. TNF-α, IL-6, MCP-1, TGF-ß1, Smad3, and P65-NF-κB were analyzed by RT-qPCR. RESULTS: Rats in the high-salt diet group exhibited impaired renal function, characterized by elevated levels of blood urea nitrogen, serum creatinine, 8-OHdG, urine albumin, and tubulointerstitial damage, along with reduced body weight. However, these effects were significantly ameliorated by Tempol administration. In the high-salt diet group, blood pressure, urinary protein, and oxidized albumin levels were notably higher compared to the normal diet group, but Tempol administration in the treatment group reversed these effects. Rats in the high-salt diet group also displayed increased levels of proinflammatory factors (TNF-α, IL-6, MCP1) and profibrotic factors (NF-κB activation, Collagen I), elevated expression of NADPH oxidation-related subunits (P65), and activation of the TGF-ß1/Smad3 signaling pathway. Tempol treatment inhibited NF-κB-mediated inflammation and TGF-ß1/Smad3-induced renal fibrosis signaling pathway activation. CONCLUSION: These findings suggest that Tempol may hold therapeutic potential for preventing and treating rats undergoing 5/6 nephrectomy. Further research is warranted to elucidate the mechanisms underlying Tempol's protective effects and its potential clinical applications. Besides, there is a discernible positive relationship between oxidized albumin and other biomarkers, such as 8-OHG, urinary protein levels, mALB, Scr, BUN, and TGF-ß1 in a High-salt diet combined with 5/6 nephrectomy rat model. These findings suggest the potential utility of oxidized albumin as a sensitive indicator for oxidative stress assessment.

The dilemma of sodium intake in preeclampsia: beneficial or detrimental?

Preeclampsia (PE) is a disorder involving de novo development of hypertension plus end organ damage after 20 weeks of gestation. PE is considered to be a heterogeneous disease. There are 2 main types of PE: early-onset (<34 weeks of gestation), which is considered to be a placental disorder and is associated with vasoconstriction, low cardiac output, and placental hypoperfusion and organ damage due to decreased microcirculation to maternal organs; and late-onset PE, which is primarily a disorder of pregnant women with obesity, diabetes, and/or cardiovascular abnormalities. In late-onset PE, there is avid sodium reabsorption by the maternal kidneys, causing hypervolemia and increased cardiac output, along with vasodilatation causing venous congestion of organs. Although PE has been a well-known disease for a long time, it is interesting to note that there is no specific sodium (salt) intake recommendation for these patients. This may be due to the fact that studies since as far back as the 1900s have shown conflicting results, and the reasons for the inconsistent findings have not been fully explained; furthermore, the type of PE in these studies was not specifically defined. Some studies suggest that sodium restriction may be detrimental in early-onset PE, but may be feasible in late-onset PE. To explore this paradox, the current review explains the hemodynamic factors involved in these 2 types of PE, summarizes the findings of the current studies, and highlights the knowledge gaps and the research needed to determine whether increase or restriction of salt or sodium intake is beneficial in different types of PE.

Sex influences blood pressure but not blood pressure variability in response to dietary sodium and potassium in salt-resistant adults.

Dietary sodium and potassium have been shown to affect blood pressure (BP) but their influence on BP variability (BPV) is less studied as is the influence of sex. The aim of this study was to compare 24 h BP and short-term BPV in response to varying dietary levels of sodium and potassium in healthy non-obese normotensive salt-resistant adults. We hypothesized that high sodium would increase short-term BP and BPV while the addition of high potassium would counteract this increase. Furthermore, we hypothesized that women would experience greater increases in BPV under high sodium conditions compared to men while potassium would attenuate this response. Thirty-seven participants (17 M/20 W; 27 ± 5 years old; BMI 24.3 ± 3 kg/m2) completed seven days each of the following randomized diets: moderate potassium/low sodium (MK/LS), moderate potassium/high sodium (MK/HS) and high potassium/high sodium (HK/HS). BP and short-term BPV were assessed using 24 h ambulatory BP monitoring starting on day 6. BPV was calculated using the average real variability (ARV) index. Twenty-four hour, daytime, and nighttime systolic BP (SBP) were lower in women compared to men regardless of diet. However, 24 h and daytime SBP were lowered in women on the HK/HS diet compared to the MK/HS diet. There were no significant effects of diet or sex for 24 h, daytime or nighttime SBP ARV. However, men exhibited a higher 24 hDBP ARV than women regardless of diet. In conclusion, a high potassium diet lowered BP under high sodium conditions in women alone while men exhibited higher short-term BPV that was not influenced by diet.

Using Genetics to Inform Interventions Related to Sodium and Potassium in Hypertension.

BACKGROUND: Hypertension is a key risk factor for major adverse cardiovascular events but remains difficult to treat in many individuals. Dietary interventions are an effective approach to lower blood pressure (BP) but are not equally effective across all individuals. BP is heritable, and genetics may be a useful tool to overcome treatment response heterogeneity. We investigated whether the genetics of BP could be used to identify individuals with hypertension who may receive a particular benefit from lowering sodium intake and boosting potassium levels. METHODS: In this observational genetic study, we leveraged cross-sectional data from up to 296 475 genotyped individuals drawn from the UK Biobank cohort for whom BP and urinary electrolytes (sodium and potassium), biomarkers of sodium and potassium intake, were measured. Biologically directed genetic scores for BP were constructed specifically among pathways related to sodium and potassium biology (pharmagenic enrichment scores), as well as unannotated genome-wide scores (conventional polygenic scores). We then tested whether there was a gene-by-environment interaction between urinary electrolytes and these genetic scores on BP. RESULTS: Genetic risk and urinary electrolytes both independently correlated with BP. However, urinary sodium was associated with a larger BP increase among individuals with higher genetic risk in sodium- and potassium-related pathways than in those with comparatively lower genetic risk. For example, each SD in urinary sodium was associated with a 1.47-mm Hg increase in systolic BP for those in the top 10% of the distribution of genetic risk in sodium and potassium transport pathways versus a 0.97-mm Hg systolic BP increase in the lowest 10% (P=1.95×10-3). This interaction with urinary sodium remained when considering estimated glomerular filtration rate and indexing sodium to urinary creatinine. There was no strong evidence of an interaction between urinary sodium and a standard genome-wide polygenic score of BP. CONCLUSIONS: The data suggest that genetic risk in sodium and potassium pathways could be used in a precision medicine model to direct interventions more specifically in the management of hypertension. Intervention studies are warranted.

Salt restriction for treatment of hypertension - current state and future directions.

PURPOSE OF REVIEW: Given the adverse effects of excess dietary sodium chloride (also known as table salt) on blood pressure (BP) and cardiovascular disease (CVD), restriction of dietary sodium is recommended by numerous guidelines. The strictest of these recommend no more than 1.5 g/day of dietary sodium among hypertensive persons. However, average dietary sodium intake in the population is closer to 5 g/day and there is debate about whether too much sodium restriction may be associated with increased CVD risk. Herein, we aim to provide a balanced update on this topic. RECENT FINDINGS: In 2021, the Salt Substitute and Stroke Study (SSaSS) demonstrated a significant reduction in BP, CVD, and death among Chinese adults randomized to a low sodium salt-substitute supplemented with potassium. This trial largely puts to rest any remaining debate about the benefits of dietary sodium restriction among persons with excess baseline intake (dietary sodium intake fell from approximately 5 down to 4 g/day in the active arm of SSaSS). However, whether achieving and maintaining a dietary sodium of less than1.5 g/day is feasible in real-world settings and whether this low an intake is harmful remain open questions. SUMMARY: Aiming for sodium intakes of 2--3 g/day in the general population and as low as 2 g/day in persons with hypertension or CVD seems most reasonable, but there is some uncertainty around lower targets.

The Burden of Gastric Cancer Attributable to High Sodium Intake: A Longitudinal Study from 1990 to 2019 in China.

BACKGROUNDS: Excessive intake of sodium is a crucial risk factor of gastric cancer. However, it is still unclear whether the profile of gastric cancer burden is attributable to high sodium intake in China. This study aims to evaluate the levels and trends of gastric cancer burden attributable to high sodium intake across China from 1990 to 2019. METHODS: We acquired data from the GBD (Global Burden of Disease Study) 2019 via the Global Health Data Exchange query tool. The details of regions from 1 January 1990 to 31 December 2019 from the China National Center for Food Safety Risk Assessment were also used. We conducted an integrated analysis on the gastric cancer burden attributable to high sodium intake among Chinese residents. The gastric cancer-related deaths, disability-adjusted life years (DALYs), age-standardized mortality rate (ASMR), and age-standardized DALYs rate (ASDR), all being calculated to be attributable to sodium intake, were reckoned as separated by age, sex, SDI, and regions. Then, the estimated annual percentage change (EAPC) was regarded as the secular trends of gastric cancer's ASMR and ASDR due to high sodium intake from 1990 to 2019. We further explored the associations between SDI (Socio-demographic index) and the ASMR and ASDR. The rates were calculated per 100,000 population as age-standardized rates. RESULTS: Briefly, the number of gastric cancer-related deaths and DALYs being attributed to high sodium intake were 37,131.48 (95% UI: 833.14 to 138,478.72) and 873,813.19 (95% UI: 19,283.13 to 3,220,231.82) in 2019; both have increased by a third since 1990. However, the ASMR decreased with an EAPC of -1.72% (95% CI: -2.11% to -1.33%), while ASDR increased with an EAPC of 0.36% (95% CI: 0.08% to 0.68%), respectively. The age-specific numbers and rates of deaths, as well as DALYs of gastric cancer being attributed to high sodium intake, elevated gradually with age. And, they were higher in males than in females. The gastric cancer burden being attributed to high sodium intake in 2019 and its temporal trends from 1990 to 2019 varied greatly by SDI quintile and geographic locations. There was a strong negative association between the EAPC in ASMR and SDI in 2019 (ρ = -0.642, p < 0.001). The EAPC in ASDR and SDI also exhibited a negative connection in 2019 (ρ = -0.538, p = 0.0012). CONCLUSIONS: Overall, using a longitudinal sample from different regions, the study presented that gastric cancer burden attributed to high sodium intake still exists seriously and varies remarkably by regions, sex, and age across China. The disparity of socioeconomic status on disease burden also exists. Integrated and precise approaches for gastric cancer prevention are anticipated in the future.

Effect of Dietary Sodium on Blood Pressure: A Crossover Trial.

Importance: Dietary sodium recommendations are debated partly due to variable blood pressure (BP) response to sodium intake. Furthermore, the BP effect of dietary sodium among individuals taking antihypertensive medications is understudied. Objectives: To examine the distribution of within-individual BP response to dietary sodium, the difference in BP between individuals allocated to consume a high- or low-sodium diet first, and whether these varied according to baseline BP and antihypertensive medication use. Design, Setting, and Participants: Prospectively allocated diet order with crossover in community-based participants enrolled between April 2021 and February 2023 in 2 US cities. A total of 213 individuals aged 50 to 75 years, including those with normotension (25%), controlled hypertension (20%), uncontrolled hypertension (31%), and untreated hypertension (25%), attended a baseline visit while consuming their usual diet, then completed 1-week high- and low-sodium diets. Intervention: High-sodium (approximately 2200 mg sodium added daily to usual diet) and low-sodium (approximately 500 mg daily total) diets. Main Outcomes and Measures: Average 24-hour ambulatory systolic and diastolic BP, mean arterial pressure, and pulse pressure. Results: Among the 213 participants who completed both high- and low-sodium diet visits, the median age was 61 years, 65% were female and 64% were Black. While consuming usual, high-sodium, and low-sodium diets, participants' median systolic BP measures were 125, 126, and 119 mm Hg, respectively. The median within-individual change in mean arterial pressure between high- and low-sodium diets was 4 mm Hg (IQR, 0-8 mm Hg; P < .001), which did not significantly differ by hypertension status. Compared with the high-sodium diet, the low-sodium diet induced a decline in mean arterial pressure in 73.4% of individuals. The commonly used threshold of a 5 mm Hg or greater decline in mean arterial pressure between a high-sodium and a low-sodium diet classified 46% of individuals as "salt sensitive." At the end of the first dietary intervention week, the mean systolic BP difference between individuals allocated to a high-sodium vs a low-sodium diet was 8 mm Hg (95% CI, 4-11 mm Hg; P < .001), which was mostly similar across subgroups of age, sex, race, hypertension, baseline BP, diabetes, and body mass index. Adverse events were mild, reported by 9.9% and 8.0% of individuals while consuming the high- and low-sodium diets, respectively. Conclusions and Relevance: Dietary sodium reduction significantly lowered BP in the majority of middle-aged to elderly adults. The decline in BP from a high- to low-sodium diet was independent of hypertension status and antihypertensive medication use, was generally consistent across subgroups, and did not result in excess adverse events. Trial Registration: ClinicalTrials.gov Identifier: NCT04258332.

Potassium intake: the Cinderella electrolyte.

Dietary guidelines recommend intake targets for some essential minerals, based on observational and experimental evidence relating mineral intake levels to health outcomes. For prevention of cardiovascular disease, reducing sodium intake and increasing potassium intake are the principal tools. While reducing sodium intake has received greatest public health priority, emerging evidence suggests that increasing potassium intake may be a more important target for cardiovascular prevention. Increased potassium intake reduces blood pressure and mitigates the hypertensive effects of excess sodium intake, and the recent large Phase III SSaSS trial reported that increasing potassium intake (and reducing sodium intake) in populations with low potassium intake and high sodium intake, through salt substitution (25% KCl, 75%NaCl), reduces the risk of stroke in patients at increased cardiovascular risk. As key sources of potassium intake include fruit, vegetables, nuts, and legumes, higher potassium intake may be associated with healthy dietary patterns. The current review makes the case that increasing potassium intake might represent a more advantageous dietary strategy for prevention of cardiovascular disease. Future research should focus on addressing the independent effect of potassium supplementation in populations with low or moderate potassium intake, and determine effective strategies to increase potassium intake from diet.

Higher versus lower sodium intake for preterm infants.

BACKGROUND: Infants born preterm are at increased risk of early hypernatraemia (above-normal blood sodium levels) and late hyponatraemia (below-normal blood sodium levels). There are concerns that imbalances of sodium intake may impact neonatal morbidities, growth and developmental outcomes. OBJECTIVES: To determine the effects of higher versus lower sodium supplementation in preterm infants. SEARCH METHODS: We searched CENTRAL in February 2023; and MEDLINE, Embase and trials registries in March and April 2022. We checked reference lists of included studies and systematic reviews where subject matter related to the intervention or population examined in this review. We compared early (< 7 days following birth), late (≥ 7 days following birth), and early and late sodium supplementation, separately. SELECTION CRITERIA: We included randomised, quasi-randomised or cluster-randomised controlled trials that compared nutritional supplementation that included higher versus lower sodium supplementation in parenteral or enteral intake, or both. Eligible participants were preterm infants born before 37 weeks' gestational age or with a birth weight less than 2500 grams, or both. We excluded studies that had prespecified differential water intakes between groups. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed eligibility and risk of bias, and extracted data. We used the GRADE approach to assess the certainty of evidence. MAIN RESULTS: We included nine studies in total. However, we were unable to extract data from one study (20 infants); some studies contributed to more than one comparison. Eight studies (241 infants) were available for quantitative meta-analysis. Four studies (103 infants) compared early higher versus lower sodium intake, and four studies (138 infants) compared late higher versus lower sodium intake. Two studies (103 infants) compared intermediate sodium supplementation (≥ 3 mmol/kg/day to < 5 mmol/kg/day) versus no supplementation, and two studies (52 infants) compared higher sodium supplementation (≥ 5 mmol/kg/day) versus no supplementation. We assessed only two studies (63 infants) as low risk of bias. Early (less than seven days following birth) higher versus lower sodium intake Early higher versus lower sodium intake may not affect mortality (risk ratio (RR) 1.02, 95% confidence interval (CI) 0.38 to 2.72; I2 = 0%; 3 studies, 83 infants; low-certainty evidence). Neurodevelopmental follow-up was not reported. Early higher versus lower sodium intake may lead to a similar incidence of hyponatraemia < 130 mmol/L (RR 0.68, 95% CI 0.40 to 1.13; I2 = 0%; 3 studies, 83 infants; low-certainty evidence) but an increased incidence of hypernatraemia ≥ 150 mmol/L (RR 1.62, 95% CI 1.00 to 2.65; I2 = 0%; 4 studies, 103 infants; risk difference (RD) 0.17, 95% CI 0.01 to 0.34; number needed to treat for an additional harmful outcome 6, 95% CI 3 to 100; low-certainty evidence). Postnatal growth failure was not reported. The evidence is uncertain for an effect on necrotising enterocolitis (RR 4.60, 95% CI 0.23 to 90.84; 1 study, 46 infants; very low-certainty evidence). Chronic lung disease at 36 weeks was not reported. Late (seven days or more following birth) higher versus lower sodium intake Late higher versus lower sodium intake may not affect mortality (RR 0.13, 95% CI 0.01 to 2.20; 1 study, 49 infants; very low-certainty evidence). Neurodevelopmental follow-up was not reported. Late higher versus lower sodium intake may reduce the incidence of hyponatraemia < 130 mmol/L (RR 0.13, 95% CI 0.03 to 0.50; I2 = 0%; 2 studies, 69 infants; RD -0.42, 95% CI -0.59 to -0.24; number needed to treat for an additional beneficial outcome 2, 95% CI 2 to 4; low-certainty evidence). The evidence is uncertain for an effect on hypernatraemia ≥ 150 mmol/L (RR 7.88, 95% CI 0.43 to 144.81; I2 = 0%; 2 studies, 69 infants; very low-certainty evidence). A single small study reported that later higher versus lower sodium intake may reduce the incidence of postnatal growth failure (RR 0.25, 95% CI 0.09 to 0.69; 1 study; 29 infants; low-certainty evidence). The evidence is uncertain for an effect on necrotising enterocolitis (RR 0.07, 95% CI 0.00 to 1.25; 1 study, 49 infants; very low-certainty evidence) and chronic lung disease (RR 2.03, 95% CI 0.80 to 5.20; 1 study, 49 infants; very low-certainty evidence). Early and late (day 1 to 28 after birth) higher versus lower sodium intake for preterm infants Early and late higher versus lower sodium intake may not have an effect on hypernatraemia ≥ 150 mmol/L (RR 2.50, 95% CI 0.63 to 10.00; 1 study, 20 infants; very low-certainty evidence). No other outcomes were reported. AUTHORS' CONCLUSIONS: Early (< 7 days following birth) higher sodium supplementation may result in an increased incidence of hypernatraemia and may result in a similar incidence of hyponatraemia compared to lower supplementation. We are uncertain if there are any effects on mortality or neonatal morbidity. Growth and longer-term development outcomes were largely unreported in trials of early sodium supplementation. Late (≥ 7 days following birth) higher sodium supplementation may reduce the incidence of hyponatraemia. We are uncertain if late higher intake affects the incidence of hypernatraemia compared to lower supplementation. Late higher sodium intake may reduce postnatal growth failure. We are uncertain if late higher sodium intake affects mortality, other neonatal morbidities or longer-term development. We are uncertain if early and late higher versus lower sodium supplementation affects outcomes.

Dietary Sodium and Human Health.

Sodium, contained in dietary salt, is essential to human life [...].

Sodium intake and the development of hypertensive disorders of pregnancy.

BACKGROUND: In nonpregnant populations, sodium intake has been associated with the development of chronic hypertension, and sodium restriction has been identified as a strategy to reduce blood pressure. Data regarding the relationship between sodium intake and the development of hypertensive disorders of pregnancy are limited and conflicting. OBJECTIVE: This study aimed to assess the association between daily periconceptional sodium intake and the risk of hypertensive disorders of pregnancy. STUDY DESIGN: This was a secondary analysis of the prospective Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-To-Be study. Individuals with nonanomalous, singleton pregnancies who completed food frequency questionnaires with recorded sodium intake in the 3 months before pregnancy were included in the analysis. Individuals whose pregnancies did not progress beyond 20 weeks of gestation were excluded from the analysis. Sodium intake was categorized as low (<2 g per day), medium (2 to <3 g per day), or high (≥3 g per day), based on thresholds used in the nonpregnant population. The primary outcome was the development of a new-onset hypertensive disorder of pregnancy, including gestational hypertension; preeclampsia; hemolysis, elevated liver enzymes, and low platelet count syndrome; superimposed preeclampsia; or eclampsia. Bivariable analyses were performed using Kruskal-Wallis and chi-square tests. Poisson regression was used to estimate adjusted incidence risk ratios with 95% confidence intervals after controlling for potentially confounding factors. RESULTS: Among 7458 individuals included in this analysis, 2336 (31%) reported low sodium intake, 2792 (37%) reported medium sodium intake, and 2330 (31%) reported high sodium intake. Individuals with high sodium intake were more likely to have chronic hypertension, to use tobacco, and to be living with obesity. The risk of developing a hypertensive disorder of pregnancy was similar among groups (medium vs low adjusted incidence risk ratio: 1.10 [95% confidence interval, 0.94-1.28]; high vs low adjusted incidence risk ratio: 1.17 [95% confidence interval, 1.00-1.37]). There was no difference in neonatal outcomes by sodium intake, including preterm birth, small-for-gestational-age neonate, and admission to the neonatal intensive care unit. CONCLUSION: Sodium intake was not associated with the risk of developing a hypertensive disorder of pregnancy. This lack of association contrasts with that between sodium intake and hypertension in the nonpregnant state and may reflect differences in the pathophysiology underlying pregnancy- vs non-pregnancy-related hypertensive disorders.

Association of Dietary Sodium-to-Potassium Ratio with Cardiometabolic Risk Factors in Korean Adults: Findings from the Korean National Health and Nutrition Examination Survey.

High-sodium and low-potassium intakes are interdependently linked to hypertension and cardiovascular diseases. We investigated the associations of dietary sodium-to-potassium (Na/K) ratio with cardiometabolic risk factors in 12,996 Korean adults (≥30 years) from the Korean National Health and Nutrition Examination Survey Ⅶ (2016-2018). Food intake was assessed through 24 h dietary recall data. Participants were divided into thirds based on their dietary Na/K ratio, with mean molar Na/K ratios of 1.11 (low), 1.92 (medium), and 3.21 (high). Although no significant associations were found between the dietary Na/K level and the risk of hypertension, obesity, and diabetes in all participants, the high Na/K ratio group had a higher risk of hypertension compared to the low Na/K ratio group in older adults (≥65 years) after adjusting for confounding factors (odds ratio = 1.38, 95% confidence interval: 1.10-1.72). Moreover, a higher Na/K ratio was associated with an increased risk of metabolic syndrome (MetS) in all participants (p for trend = 0.0020). Within MetS components, abdominal obesity, elevated triglycerides, and elevated blood pressure were positively associated with the Na/K level. The food groups positively associated with a lower Na/K ratio were fruits, unsalted vegetables, nuts, potatoes, and dairy products. These findings suggest that a high dietary Na/K ratio may be an important risk factor for hypertension in older adults and MetS in all adults.

A short, animated storytelling video about sodium intake as a major cardiovascular risk factor and recommendations for a healthy diet: an online, randomized, controlled trial.

BACKGROUND: Increased uptake of sodium is a major cause for cardiovascular disease and mortality. Reduction of daily salt intake below a reference level of 2 g per day (the equivalent to 5 g salt/day) is known to effectively reduce cardiovascular mortality. The widespread use of social media, with a constant increase in video consumption, is opening new avenues for the dissemination of innovative and scalable approaches to health-related information and recommendations for a healthy diet, such as via video interventions with short animated stories (SAS). OBJECTIVE: This study will evaluate the effect of a sodium intake-SAS video intervention on immediate and medium-term knowledge about dietary sodium. Beyond that, immediate and medium-term effects on behavioral expectation to reduce sodium intake as well as voluntary post-trial engagement with the video content will be examined. METHODS: In this 4-armed, parallel, randomized controlled trial, 10,000 adult, US participants will be randomly assigned to (1) a short, animated storytelling intervention video on sodium as a cardiovascular disease risk factor followed by surveys assessing the facts on sodium and cardiovascular disease conveyed in the video (2) the surveys only, (3) an attention placebo control video followed by the before mentioned surveys, and (4) an arm that is exposed to neither the video nor the surveys. Two weeks later, participants in all four arms will complete all of the surveys. RESULTS: Primary outcomes are the immediate and medium-term effects of the short, animated storytelling intervention video on knowledge about dietary sodium. Secondary outcomes are immediate and medium-term effects of the short, animated storytelling intervention on behavioral expectation to reduce sodium intake as well as voluntary post-trial engagement with the video content. CONCLUSION: This study will extend the knowledge on the effects of short, animated storytelling for the containment of the global cardiovascular disease burden. Knowledge on the groups that may be more likely to voluntarily engage with SAS video content will help to improve targeting of future interventions towards audiences at risk. TRIAL REGISTRATION {2A}: ClinicalTrials.gov NCT05735457. Registered on February 21, 2023.