The science of salt: a systematic review of clinical salt studies 2013 to 2014

Dissociation of Hypertension and Renal Damage After Cessation of High-Salt Diet in Dahl Rats

BACKGROUND

Every year, thousands of patients with hypertension reduce salt consumption in an effort to control their blood pressure. However, hypertension has a self-sustaining character in a significant part of the population. We hypothesized that chronic hypertension leads to irreversible renal damage that remains after removing the trigger, causing an elevation of the initial blood pressure.

METHODS

Dahl salt-sensitive rat model was used for chronic, continuous observation of blood pressure. Rats were fed a high salt diet to induce hypertension, and then the diet was switched back to normal sodium content.

RESULTS

We found that developed hypertension was irreversible by salt cessation: after a short period of reduction, blood pressure grew even higher than in the high-salt phase. Notably, the self-sustaining phase of hypertension was sensitive to benzamil treatment due to sustaining epithelial sodium channel hyperactivity, as shown with patch-clamp analysis. Glomerular damage and proteinuria were also irreversible. In contrast, some mechanisms, contributing to the development of salt-sensitive hypertension, normalized after salt restriction. Thus, flow cytometry demonstrated that dietary salt reduction in hypertensive animals decreased the number of total CD45+, CD3+CD4+, and CD3+CD8+ cells in renal tissues. Also, we found tubular recovery and improvement of glomerular filtration rate in the postsalt period versus a high-salt diet.

CONCLUSIONS

Based on earlier publications and current data, poor response to salt restriction is due to the differential contribution of the factors recognized in the developmental phase of hypertension. We suggest that proteinuria or electrolyte transport can be prioritized over therapeutic targets of inflammatory response.

A mobile phone application intervention to promote healthy salt intake among adults: Protocol for a randomized controlled study (Preprint)

Background

There is sound evidence associating high salt intake and a greater risk of cardiovascular and noncardiovascular diseases. High salt intake has been observed in several populations worldwide. Therefore, promoting healthier salt consumption has been encouraged as a low-cost strategy to reduce this risk factor. However, these strategies need to be sound, built on theoretical and methodological bases, and consider the target population’s context.

Objective

This protocol aims to describe a mobile phone app intervention to promote healthy salt intake among adults.

Methods

This is an experimental and longitudinal study protocol conducted in three modules. Module 1 refers to the planning of the intervention based on the Behaviour Change Wheel framework. Module 2 is the development of the mobile phone app intervention based on the date of module 1. In module 3, the intervention will be evaluated using a randomized controlled study, with three steps of data collection in a 2-month follow-up in a sample of 86 adults (43 participants for each group: the control group and intervention group) recruited from the primary health care centers of a Brazilian town. The discretionary salt intake questionnaire will assess salt consumption, the app usability will be assessed using the System Usability Scale, and psychosocial variables (habit, intention, and self-efficacy) will also be measured.

Results

Recruitment began in October 2021, and the follow-up will end in August 2022. The results of this study are expected to be published in 2023.

Conclusions

Results from this study will help people to control salt intake when cooking at home, will stimulate self-care, will work as an alternative or supportive method in the relationship between health care professionals and patients, and will contribute to implementing the app intervention to promote healthy salt intake on a large scale.

Trial Registration

The Brazilian Clinical Trials Registry RBR-4s8qyyq; https://ensaiosclinicos.gov.br/rg/RBR-4s8qyyq

International Registered Report Identifier (IRRID)

DERR1-10.2196/37853

The role of diet in renal cell carcinoma incidence: an umbrella review of meta-analyses of observational studies

BACKGROUND

Evidence associating diet with the incidence of renal cell carcinoma (RCC) is inconclusive. We aimed to summarize evidence associating dietary factors with RCC incidence and assess the strength and validity of this evidence.

METHODS

We conducted an umbrella review of systematic reviews or meta-analyses (SRoMAs) that assessed the association between diet and RCC incidence. Through April 2021, PubMed, Web of Science, Embase, The Cochrane Library, Scopus, and WCRF were searched. Two independent reviewers selected studies, extracted data, and appraised the quality of SRoMAs. According to credibility assessment criteria, evidence can be divided into five categories: convincing (class I), highly suggestive (class II), suggestive (class III), weak (class IV), and nonsignificant (class V).

RESULTS

Twenty-nine meta-analyses were obtained after screening. After excluding 7 overlapping meta-analyses, 22 meta-analyses including 502 individual studies and 64 summary hazard ratios for RCC incidence were included: dietary patterns or dietary quality indices (n = 6), foods (n = 13), beverages (n = 4), alcohol (n = 7), macronutrients (n =15), and micronutrients (n =19). No meta-analyses had high methodological quality. Five meta-analyses exhibited small study effects; one meta-analysis showed evidence of excess significance bias. No dietary factors showed convincing or highly suggestive evidence of association with RCC in the overall analysis. Two protective factors had suggestive evidence (vegetables (0.74, 95% confidence interval 0.63 to 0.86) and vitamin C (0.77, 0.66 to 0.90)) in overall analysis. One protective factor had convincing evidence (moderate drinking (0.77, 0.70 to 0.84)) in Europe and North America and one protective factor had highly suggestive evidence (cruciferous vegetables (0.78, 0.70 to 0.86)) in North America.

CONCLUSIONS

Although many meta-analyses have assessed associations between dietary factors and RCC, no high-quality evidence exists (classes I and II) in the overall analysis. Increased intake of vegetables and vitamin C is negatively associated with RCC risk. Moderate drinking might be beneficial for Europeans and North Americans, and cruciferous vegetables might be beneficial to North Americans, but the results should be interpreted with caution. More researches are needed in the future.

TRIAL REGISTRATION

PROSPERO CRD42021246619.

Nutrient Composition of Foods Marketed to Children or Adolescents Sold in the Spanish Market: Are They Any Better?

Healthy eating is essential for the growth and development of children and adolescents. Eating habits established in childhood continue into adulthood. In Spain, the frequent promotion of foods with low nutritional value is already considered a threat to the health of the population, particularly to children and adolescents. In this work, we analyse 3209 foods from the Food Database, BADALI. Foods were classified as marketed to children or adolescents according to the advertising on the packaging, television or internet. We found that 17.5% of foods in the database were marketed to this population and 97% of those were considered unhealthy following the Pan American Health Organization Nutrient Profile Model (PAHO-NPM). In the total of foods for children or adolescents, 61.5% were high in fat, 58.5% in free-sugar, 45.4% in saturated fat and 45% in sodium. Foods marketed to them presented higher amounts of carbohydrates and sugar, while lower protein and fibre content than the rest. There was also considerable variability in levels of the other nutrients found in these products, which depended largely on the food group. According to our findings, there is a tendency for products marketed to children or adolescents to be unhealthy and of a poorer nutritional quality than those not targeted at them.

What methods have been used to estimate salt intake? A systematic review

The relationship between salt intake and cardiovascular diseases is a contemporary scientific controversy, which has been attributed to the limits of the measures of salt intake used in the studies. Thus, this article sought to systematically review the literature on the methods used to estimate salt intake in different study designs. Of the 124 articles, 60.5% used only biochemical measures, 26.6% only self-report measures and 12.9% reported the combined use of both methods. The 24-hour urinary sodium excretion was the predominant biochemical method (79.1%) and the Food Frequency Questionnaire was the predominant self-report measure (36.4%). Interventional studies used mostly 24-hour urinary sodium excretion; while longitudinal studies used self-report measures. The question guiding the study and its design, as well as constraints related to costs, sample size and feasibility seems to influence the choice of the type of measurement.

The International Consortium for Quality Research on Dietary Sodium/Salt (TRUE) position statement on the use of 24-hour, spot, and short duration (<24 hours) timed urine collections to assess dietary sodium intake

The International Consortium for Quality Research on Dietary Sodium/Salt (TRUE) is a coalition of intentional and national health and scientific organizations formed because of concerns low-quality research methods were creating controversy regarding dietary salt reduction. One of the main sources of controversy is believed related to errors in estimating sodium intake with urine studies. The recommendations and positions in this manuscript were generated following a series of systematic reviews and analyses by experts in hypertension, nutrition, statistics, and dietary sodium. To assess the population's current 24-hour dietary sodium ingestion, single complete 24-hour urine samples, collected over a series of days from a representative population sample, were recommended. To accurately estimate usual dietary sodium at the individual level, at least 3 non-consecutive complete 24-hour urine collections obtained over a series of days that reflect the usual short-term variations in dietary pattern were recommended. Multiple 24-hour urine collections over several years were recommended to estimate an individual's usual long-term sodium intake. The role of single spot or short duration timed urine collections in assessing population average sodium intake requires more research. Single or multiple spot or short duration timed urine collections are not recommended for assessing an individual's sodium intake especially in relationship to health outcomes. The recommendations should be applied by scientific review committees, granting agencies, editors and journal reviewers, investigators, policymakers, and those developing and creating dietary sodium recommendations. Low-quality research on dietary sodium/salt should not be funded, conducted, or published.

Sodium Content of Processed Foods Available in the Mexican Market

BACKGROUND

Sodium intake is related to several adverse health outcomes, such as hypertension and cardiovascular diseases. Processed foods are major contributors to the population's sodium intake. The aim of the present study was to determine sodium levels in Mexican packaged foods, as well as to evaluate the proportion of foods that comply with sodium benchmark targets set by the United Kingdom Food Standards Agency (UK FSA) and those set by the Mexican Commission for the Protection of Health Risks (COFEPRIS). We also evaluated the proportion of foods that exceeded the Pan American Health Organization (PAHO) targets.

METHODS

This was a cross-sectional study that comprised data collected from the package of 2248 processed foods from selected supermarkets in Mexico.

RESULTS

Many processed food categories contained an excessive amount of sodium. Processed meats, ham, bacon and sausages, had the highest concentrations. The proportion of foods classified as compliant in our sample was lower for international targets (FSA UK and PAHO) compared to the Mexican COFEPRIS criteria.

CONCLUSIONS

These data provided a critical baseline assessment for monitoring sodium levels in Mexican processed foods.

Dietary sources of salt intake in adults and older people: a population-based study in a Brazilian town

OBJECTIVE

To assess salt intake and its dietary sources using biochemical and self-report methods and to characterize salt intake according to sociodemographic and disease-related variables in a sample of the Brazilian population.

DESIGN

Population-based cross-sectional survey.

SETTING

Salt intake was assessed by biochemical (24 h urinary Na excretion) and self-report methods (sodium FFQ, 24 h dietary recall, seasoned-salt questionnaire, discretionary-salt questionnaire and total reported salt intake).ParticipantsAdults and older people (n 517) aged 20-80 years, living in Artur Nogueira, São Paulo, Brazil.

RESULTS

Mean salt intake based on 24 h urinary Na excretion and total reported salt intake was 10·5 and 11·0 g/d, respectively; both measures were significantly correlated. Discretionary salt and seasoned salt were the most important sources of salt intake (68·2 %). Men in the study consumed more salt than women as estimated by 24 h urinary Na excretion (11·7 v. 9·6 g salt/d; P&lt;0·0001). Participants known to be hypertensive added more salt to their meals but consumed less salty ultra-processed foods. Waist circumference in both sexes and BMI were positively correlated with salt intake estimated by 24 h urinary Na excretion. In addition, regression analysis revealed that being a young male or having a high waist circumference was a predictor of higher salt intake.

CONCLUSIONS

Salt intake in this population was well above the recommended amount. The main source of salt intake came from salt added during cooking. Salt intake varied according to sex and waist circumference.

Low potassium and high sodium intakes: a double health threat to Cape Verdeans

BACKGROUND

Cape Verde presents a high rate of cardiovascular diseases. Low potassium and high sodium intakes are related to cardiovascular diseases. However, studies regarding these two micronutrients continue to be rare in African urban settings. This work aims to estimate potassium and sodium intakes and to analyse the self-reported salt intake by gender and by type of urban area in the city of Praia - the capital of Cape Verde.

METHODS

In the first stage (n = 1912), an intra-urban study was designed in two types of urban areas (formal and informal), using a sampling strategy based on random selection of geographical coordinates, in order to apply a questionnaire. In a second stage, a 24-h dietary recall and anthropometric measurements were performed by local nutritionists. Potassium and sodium intakes were estimated for 599 participants (149 men and 450 women). Non-parametric methods (including quantile regression) were used in the statistical analysis.

RESULTS

In informal areas, a higher percentage of women reported having hypertension (31.0%) compared to formal areas (19.7%). Based on 24-h dietary recall, median potassium intake for men was 2924.2 mg/day and for women and 2562.6 mg/day. Almost 70.0% of men and 80.0% of women ingested less than the recommended 3510 mg/day of potassium. In informal areas, men and women presented high medians of sodium intakes compared to formal areas (men: 4131.2 vs 3014.6 mg/day and women: 3243.4 vs 2522.4 mg/day). On the other hand, the percentage of participants exceeding 2000 mg/day for sodium was high (≥70.8%), even for participants that self-reported low-salt intake. Quantile regression models revealed effects of the type of urban area and gender in the potassium and sodium intakes, at least, in some quartiles, accounting for age, academic qualifications, and professional situation.

CONCLUSIONS

A low potassium intake and a high sodium intake were found in Praia. Thus, efficient health education campaigns and health promotion are needed and should be tailored considering gender and urban areas.

Epithelial sodium channel blockade and new β-ENaC polymorphisms among normotensive and hypertensive adult Nigerians

We sought to determine the effect of amiloride on blood pressure (BP) and the presence of polymorphisms of the β-subunit of the epithelial sodium channel (ENaC) among normotensive (NT) and hypertensive (HT) Nigerians. Healthy volunteers-47 NT and 53 age-matched HT were recruited after giving informed consent. Subjects were salt-loaded with 200 mmol of NaCl daily for 5 days. Following a week washout period, salt-loading was repeated in addition to the administration of 5 mg amiloride daily for five days. Blood pressure, plasma and urine electrolytes were measured at baseline, after salt-loading and after salt-loading plus amiloride. PCR amplicons were sequenced for β-ENaC polymorphisms. Salt-loading led to a significant increase (p < 0.05) in SBP among NT and HT and in DBP (p < 0.001) only among HT. Amiloride reduced SBP and DBP to below baseline levels in NT (p < 0.05) and HT (p < 0.001) subjects. Five of the subjects had the β-T594M polymorphism, HT 3/53; NT 2/47 (p = 0.75). Four previously unreported β-ENaC mutations were recorded: E632V and E636V, respectively, among two HT subjects, D638Y in another HT and L628Q in one NT subject. We showed the presence of β-ENaC polymorphisms among our populace and the possible usefulness of amiloride as a single antihypertensive among Nigerians.

The Science of Salt: A regularly updated systematic review of the implementation of salt reduction interventions (September 2016-February 2017)

This periodic review aims to identify, summarize, and appraise studies relating to the implementation of salt reduction strategies that were published between September 2016 and February 2017. A total of 41 studies were included as relevant to the design, assessment, and implementation of salt reduction strategies, and a detailed appraisal was conducted on the seven studies that evaluated the impact of salt reduction strategies. Of these, three were national studies or included large populations and four were conducted in communities with small participant sample sizes. Each study used a different strategy for reducing salt intake varying from category-specific sodium targets for packaged food to use of a low-sodium salt substitute to behavior change interventions. Four studies found statistically significant decreases in dietary salt intake and one study showed statistically significant decreases in mean sodium density of packaged food products. Four of the seven studies used either spot or 24-hour urine samples to measure dietary salt intake and five were conducted in East or Southeast Asia-two of which were in low- and middle-income countries. Study quality varied among the seven studies and all except one had one or more risks related to bias.

Characterization of Breakfast Cereals Available in the Mexican Market: Sodium and Sugar Content

Preschool Mexican children consume 7% of their total energy intake from processed breakfast cereals. This study characterized the nutritional quality and labelling (claims and Guideline Daily Amount (GDA)) of the packaged breakfast cereals available in the Mexican market. Photographs of all breakfast cereals available in the 9 main food retail chains in the country were taken. The nutrition quality of cereals was assessed using the United Kingdom Nutrient Profiling Model (UKNPM). Claims were classified using the International Network for Food and Obesity/non-communicable Diseases Research, Monitoring and Action Support (INFORMAS) taxonomy and the GDA was defined according to the Mexican regulation, NOM-051. Overall, a total of 371 different breakfast cereals were analysed. The nutritional profile showed that 68.7% were classified as “less healthy”. GDAs and claims were displayed more frequently on the “less healthy” cereals. Breakfast cereals within the “less healthy” category had significantly higher content of energy, sugar and sodium (p < 0.001). Most of the claims were displayed in the “less healthy” cereals (n = 313). This study has shown that there is a lack of consistency between the labelling on the front of the pack and the nutritional quality of breakfast cereals.

Interaction between Single Nucleotide Polymorphism and Urinary Sodium, Potassium, and Sodium-Potassium Ratio on the Risk of Hypertension in Korean Adults

Hypertension is a complex disease explained with diverse factors including environmental factors and genetic factors. The objectives of this study were to determine the interaction effects between gene variants and 24 h estimated urinary sodium and potassium excretion and sodium-potassium excretion ratios on the risk of hypertension. A total of 8839 participants were included in the genome-wide association study (GWAS) to find genetic factors associated with hypertension. Tanaka and Kawasaki formulas were applied to estimate 24 h urinary sodium and potassium excretion. A total of 4414 participants were included in interaction analyses to identify the interaction effects of gene variants according to 24 h estimated urinary factors on the risk of hypertension. CSK rs1378942 and CSK-MIR4513 rs3784789 were significantly modified by urinary sodium-potassium excretion ratio. In addition, MKLN rs1643270 with urinary potassium excretion, LOC101929750 rs7554672 with urinary sodium and potassium excretion, and TENM4 rs10466739 with urinary sodium-potassium excretion ratio showed significant interaction effects. The present study results indicated that the mutant alleles of CSK rs1378942 and CSK-MIR4513 rs3784789 had the strongest protective effects against hypertension in the middle group of 24 h estimated urinary sodium-potassium excretion ratio. Further studies are needed to replicate these analyses in other populations.

Socioeconomic Determinants of Sodium Intake in Adult Populations of High-Income Countries: A Systematic Review and Meta-Analysis

BACKGROUND

A poorer quality diet among individuals with low socioeconomic status (SES) may partly explain the higher burden of noncommunicable disease among disadvantaged populations. Because there is a link between sodium intake and noncommunicable diseases, we systematically reviewed the current evidence on the social patterning of sodium intake.

OBJECTIVES

To conduct a systematic review and a meta-analysis of the evidence on the association between SES and sodium intake in healthy adult populations of high-income countries.

SEARCH METHODS

We followed the PRISMA-Equity guidelines in conducting a literature search that ended June 3, 2016, via MEDLINE, Embase, and SciELO. We imposed no publication date limits.

SELECTION CRITERIA

We considered only peer-reviewed articles meeting the following inclusion criteria: (1) reported a measure of sodium intake disaggregated by at least 1 measure of SES (education, income, occupation, or any other socioeconomic indicator); (2) were written in English, Spanish, Portuguese, French, or Italian; and (3) were conducted in a high-income country as defined by the World Bank (i.e., per capita national gross income was higher than $12 746). We also excluded articles that exclusively sampled low-SES individuals, pregnant women, children, adolescents, elderly participants, or diseased patients or that reported results from a trial or intervention.

DATA COLLECTION AND ANALYSIS

As summary measures, we extracted (1) the direction (positive, negative, or neutral) and the magnitude of the association between each SES indicator and sodium intake, and (2) the estimated sodium intake according to SES level. When possible and if previously unreported, we calculated the magnitude of the relative difference in sodium intake between high- and low-SES groups for each article, applying this formula: ([value for high-SES group - value for low-SES group]/[value for high-SES group]) × 100. We considered an association significant if reported as such, and we set an arbitrary 10% relative difference as clinically relevant and significant. We conducted a meta-analysis of the relative difference in sodium intake between high- and low-SES groups. We included articles in the meta-analysis if they reported urine-based sodium estimates and provided the total participant numbers in the low- and high-SES groups, the estimated sodium intake means for each group (in mg/day or convertible units), and the SDs (or transformable measures). We chose a random-effects model to account for both within-study and between-study variance.

MAIN RESULTS

Fifty-one articles covering 19 high-income countries met our inclusion criteria. Of these, 22 used urine-based methods to assess sodium intake, and 30 used dietary surveys. These articles assessed 171 associations between SES and sodium intake. Among urine-based estimates, 67% were negative (higher sodium intake in people of low SES), 3% positive, and 30% neutral. Among diet-based estimates, 41% were negative, 21% positive, and 38% neutral. The random-effects model indicated a 14% relative difference between low- and high-SES groups (95% confidence interval [CI] = -18, -9), corresponding to a global 503 milligrams per day (95% CI = 461, 545) of higher sodium intake among people of low SES.

CONCLUSIONS

People of low SES consume more sodium than do people of high SES, confirming the current evidence on socioeconomic disparities in diet, which may influence the disproportionate noncommunicable disease burden among disadvantaged socioeconomic groups. Public Health Implications. It is necessary to focus on disadvantaged populations to achieve an equitable reduction in sodium intake to a population mean of 2 grams per day as part of the World Health Organization's target to achieve a 25% relative reduction in noncommunicable disease mortality by 2025.

The Science of Salt: A Systematic Review of Quality Clinical Salt Outcome Studies June 2014 to May 2015

Studies identified from an updated systematic review (from June 2014 to May 2015) on the impact of dietary salt intake on clinical and population health are reviewed. Randomized controlled trials, cohort studies, and meta-analyses of these study types on the effect of sodium intake on blood pressure, or any substantive adverse health outcomes were identified from MEDLINE searches and quality indicators were used to select studies that were relevant to clinical and public health. From 6920 studies identified in the literature search, 144 studies were selected for review, of which only three (n=233,680) met inclusion criteria. Between them, the three studies demonstrated a harmful association between excess dietary salt and all-cause mortality, noncardiovascular and cardiovascular disease mortality, and headache. None of the included studies found harm from lowering dietary salt. The findings of this systematic review are consistent with the large body of research supportive of efforts to reduce population salt intake and congruent with our last annual review from June 2013 to May 2014.

Genome-Wide Gene-Sodium Interaction Analyses on Blood Pressure: The Genetic Epidemiology Network of Salt-Sensitivity Study

We performed genome-wide analyses to identify genomic loci that interact with sodium to influence blood pressure (BP) using single-marker-based (1 and 2 df joint tests) and gene-based tests among 1876 Chinese participants of the Genetic Epidemiology Network of Salt-Sensitivity (GenSalt) study. Among GenSalt participants, the average of 3 urine samples was used to estimate sodium excretion. Nine BP measurements were taken using a random zero sphygmomanometer. A total of 2.05 million single-nucleotide polymorphisms were imputed using Affymetrix 6.0 genotype data and the Chinese Han of Beijing and Japanese of Tokyo HapMap reference panel. Promising findings (P<1.00×10(-4)) from GenSalt were evaluated for replication among 775 Chinese participants of the Multi-Ethnic Study of Atherosclerosis (MESA). Single-nucleotide polymorphism and gene-based results were meta-analyzed across the GenSalt and MESA studies to determine genome-wide significance. The 1 df tests identified interactions for UST rs13211840 on diastolic BP (P=3.13×10(-9)). The 2 df tests additionally identified associations for CLGN rs2567241 (P=3.90×10(-12)) and LOC105369882 rs11104632 (P=4.51×10(-8)) with systolic BP. The CLGN variant rs2567241 was also associated with diastolic BP (P=3.11×10(-22)) and mean arterial pressure (P=2.86×10(-15)). Genome-wide gene-based analysis identified MKNK1 (P=6.70×10(-7)), C2orf80 (P<1.00×10(-12)), EPHA6 (P=2.88×10(-7)), SCOC-AS1 (P=4.35×10(-14)), SCOC (P=6.46×10(-11)), CLGN (P=3.68×10(-13)), MGAT4D (P=4.73×10(-11)), ARHGAP42 (P≤1.00×10(-12)), CASP4 (P=1.31×10(-8)), and LINC01478 (P=6.75×10(-10)) that were associated with at least 1 BP phenotype. In summary, we identified 8 novel and 1 previously reported BP loci through the examination of single-nucleotide polymorphism and gene-based interactions with sodium.

State-level and community-level salt reduction initiatives: a systematic review of global programmes and their impact

BACKGROUND

High-salt diets are linked to elevated blood pressure, a major risk factor for cardiovascular diseases, particularly stroke. State and community salt reduction strategies may complement nationally led initiatives and contribute to achieving global salt reduction targets. We aim to systematically review such interventions and document reported impact where programmes have been evaluated.

METHODS

Electronic databases were searched up to June 2015 using terms 'salt' or 'sodium' and 'state' and 'community' in combination with 'campaign', 'initiative', 'project', 'strategy', 'intervention' or 'programme'. Data from evaluated and unevaluated interventions were included. Studies were analysed in relation to intervention components and outcome measures and appraised for quality using a Cochrane Risk-of-Bias Tool.

RESULTS

39 state and community programmes were identified. Settings varied from whole communities (n=23), state-owned buildings (n=5), schools (n=7), workplaces (n=3) and correctional facilities (n=1). Strategies included nutrition education programmes, public education campaigns, changes to the food environment, other 'novel' approaches and multifaceted approaches. Of the 28 studies that evaluated intervention effectiveness, significant reductions were observed in terms of salt intake from dietary assessment (n=7), urinary sodium excretion (n=8), blood pressure (n=11) and sodium in foods (n=9). Six studies reported positive changes in consumer knowledge, attitudes and behaviours. All but two studies had some methodological limitations.

CONCLUSIONS

State and community salt reduction programmes may be effective in a range of settings but more robust evaluation methods are needed. Scaling up these efforts in coordination with national initiatives could provide the most effective and sustainable approach to reducing population salt intake.