Association between 24-h urinary sodium excretion and obesity in Korean adults: A multicenter study

Dietary salt intake and kidney function in rural Senegalese populations: a cross-sectional study

INTRODUCTION

High salt intake is a major risk factor for hypertension and its complications such as chronic kidney disease (CKD) and cardiovascular diseases. The present study aimed to determine level of sodium consumption and its relation with kidney function in the rural populations of Ferlo (centre of Senegal).

SUBJECTS AND METHODS

We performed a cross-sectional study including 400 volunteers aged > 18 years. Clinical, biological and dietary data were collected during household visits. Daily sodium intake was measured in the 24 h-urine outpout and CKD was defined as eGFR < 60 ml/min. Linear regression analysis was used to assess association between sodium intake and covariates.

RESULTS

Mean age was 46.42 ± 15.60 and sex-ratio was 1.05. Prevalence of hypertension, CKD and overweight were 21.5, 11.7 and 20.5%, respectively. The median daily salt intake was 11.7 g with interquartile range of 14.8 g. Only 11.25% of participants consumed less than 5 g/day. After multivariate analysis, high salt intake was associated with age > 60 years, overweight and CKD. However, gender and hypertension were not significantly associated with salt intake. Industrial broths (91.5%) and bread (85%) represented the main sources of dietary salt.

CONCLUSION

This study revealed high levels of daily salt intake contrasting with low potassium intakes in the majority of participants. Participants with CKD, overweight and age > 60 years presented higher salt consumption. Stategies to reduce salt consumption are urgently needed to reduce burden of CKD in rural Senegalese populations.

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.

Hepatic Transcriptomics Reveals Reduced Lipogenesis in High-Salt Diet Mice

It has been demonstrated that a high salt diet (HSD) increases the risk of cardiovascular disease and metabolic dysfunction. In particular, the impact and molecular mechanisms of long-term HSD on hepatic metabolism remain largely unknown. To identify differentially expressed genes (DEGs) affecting the metabolism of liver tissues from HSD and control groups, a transcriptome analysis of liver tissues was performed in this study. As a result of the transcriptome analysis, the expression of genes related to lipid and steroid biosynthesis (such as Fasn, Scd1, and Cyp7a1) was significantly reduced in the livers of HSD mice. Additionally, several gene ontology (GO) terms have been identified as associated with metabolic processes in the liver, including the lipid metabolic process (GO: 0006629) and the steroid metabolic process (GO: 0008202). An additional quantitative RT-qPCR analysis was conducted to confirm six down-regulated genes and two up-regulated genes. Our findings provide a theoretical basis for further investigation of HSD-induced metabolic disorders.

Comparison between 24-hour diet recall and 24-hour urine collection for estimating sodium and potassium intakes and their ratio among Korean adults

BACKGROUND/OBJECTIVES

This study aimed to compare 24-h diet recall (DR) and 24-h urine collection (UC) for estimating sodium and potassium intakes and their ratio (Na/K), identifying factors associated with sodium and potassium intakes and Na/K, and identifying those who were likely to underestimate sodium and potassium intakes by DR.

SUBJECTS/METHODS

A total of 640 healthy adults aged 19-69 yrs completed a questionnaire survey, salty taste assessment, anthropometric measurement, two 24-h DRs, and two 24-h UCs.

RESULTS

The mean sodium and potassium intakes and Na/K were 3,755 mg/d, 2,737 mg/d, and 1.45 according to DR, and 4,145 mg/d, 2,812 mg/d, and 1.57 according to UC, with percentage differences of -9.4%, -2.7%, and -7.6% in the values between the two methods, respectively. Men, older adults, smokers, obese individuals, those who consumed all the liquid in the soup, and those who were found to be salty in the salty taste assessment consumed significantly more sodium; older adults, the heavy- activity group, and obese individuals consumed more potassium; and men, younger adults, smokers, and obese individuals had a significantly higher Na/K, according to UC. Compared with UC, DR was more likely to underestimate sodium intake in older adults, smokers, obese individuals, those who consumed all the liquid in the soup, and those who consumed eating-out/delivery food at least once a day, and potassium intake in older adults, the heavy-activity group, and obese individuals.

CONCLUSIONS

The mean sodium and potassium intakes and Na/K estimated by DR were comparable to those measured by UC. However, the association of sodium and potassium intakes with sociodemographic and health-related factors showed inconsistent results when estimated by DR and UC. Factors influencing the underestimation of sodium intake by DR compared to UC should be further investigated.

The association between dietary sodium intake and obesity in adults by sodium intake assessment methods: a review of systematic reviews and re-meta-analysis

BACKGROUND/OBJECTIVES

The scientific evidence of a sodium-obesity association is limited by sodium intake assessments. Our specific aim is to synthesize the association between dietary sodium intake and obesity across the sodium intake assessments as evidenced by systematic reviews in adults.

SUBJECTS/METHODS

A systematic search identified systematic reviews comparing the association of dietary sodium intakes with obesity-related outcomes such as body mass index (BMI), body weight, waist circumference, and risk of (abdominal) obesity. We searched PubMed on October 24, 2022. To assess the Risk of Bias in Systematic Reviews (ROBIS), we employed the ROBIS tool.

RESULTS

This review included 3 systematic reviews, consisting of 39 unique observational studies (35 cross-sectional studies and 4 longitudinal studies) and 15 randomized controlled trials (RCTs). We found consistently positive associations between dietary sodium intake and obesity-related outcomes in cross-sectional studies. Studies that used 24-h urine collection indicated a greater BMI for those with higher sodium intake (mean difference = 2.27 kg/m2; 95% confidence interval [CI], 1.59-2.51; P < 0.001; I2 = 77%) compared to studies that used spot urine (mean difference = 1.34 kg/m2; 95% CI, 1.13-1.55; P < 0.001; I2 = 95%) and dietary methods (mean difference = 0.85 kg/m2; 95% CI, 0.1-1.51; P < 0.05; I2 = 95%).

CONCLUSIONS

Quantitative synthesis of the systematic reviews has shown that cross-sectional associations between dietary sodium intake and obesity outcomes were substantially different across the sodium intake assessments. We need more high-quality prospective cohort studies and RCTs using 24-h urine collection to examine the causal effects of sodium intake on obesity.

Urinary Sodium Excretion and Obesity Markers among Bangladeshi Adult Population: Pooled Data from Three Cohort Studies

We evaluated the relationship of urinary sodium excretion with a conditional mean, 10th and 90th percentiles of body mass index (BMI), and waist circumference among 10,034 person-visits of Bangladeshi population. We fitted linear mixed models with participant-level random intercept and restricted maximum likelihood estimation for conditional mean models; and quantile mixed-effect models with participant-level random intercept and Laplace estimation for 10th and 90th percentiles models. For each 100 mmol/24 h increase in urinary sodium excretion, participants had a 0.10 kg/m2 (95% CI: 0.00, 0.10) increase in the mean; a 0.39 kg/m2 (95% CI: 0.23, 0.54) increase in the 10th percentile; and a 0.59 kg/m2 (95% CI: 0.39, 0.78) increase in the 90th percentile of BMI. For each 100 mmol/24 h increase in urinary sodium excretion, participants had a 0.20 cm (95% CI: 0.10, 0.30) increase in mean; a 0.18 cm (95% CI: -0.03, 0.40) change in the 10th percentile; and a 0.23 cm (95% CI: 0.03, 0.43) increase in the 90th percentile of waist circumference. We found a modest association between urine sodium and conditional mean of BMI and waist circumference. The magnitude of associations between urine sodium and the 10th and 90th percentile BMI distributions were higher compared to the conditional mean models, suggesting high sodium intake could be more detrimental to underweight and obese participants.

The association between salt intake and blood pressure is mediated by body mass index but modified by hypertension: The ELSA-Brasil study

High salt intake has been linked to both obesity and high blood pressure (BP). Part of the variability of BP attributed to salt intake might be BMI-mediated. To investigate whether hypertension would be an effect modifier in the complex network including salt intake, obesity, and BP, we tested the hypothesis that salt intake has direct and BMI-mediated effects on systolic (SBP) and diastolic blood pressure (DBP). Data from 9,028 participants (aged 34-75 years, 53.6% women) were analyzed. A validated formula was used to estimate daily salt intake from the sodium excretion (12 h urine collection). A path model adjusted for covariates was designed in which salt intake has both a direct and a BMI-mediated effect on BP. In normotensives, standardized beta coefficients showed significant direct (Men: 0.058 and 0.052, Women: 0.072 and 0,061, P < 0.05) and BMI-mediated (Men: 0.040 and 0.065, Women: 0.038 and 0.067, P < 0.05) effect of salt intake on the SBP and DBP, respectively. However, in hypertensive individuals, neither the direct (Men: 0.006 and 0.056, Women: 0.048 and 0.017) nor the indirect effect (Men: -0.044 and 0.014, Women: 0.011 and 0.050) of salt intake on the SBP and DBP were significant. These data suggest that cardiovascular risk stratification should consider the complex interaction between salt intake and weight gain, and their effects on BP of normotensive and hypertensive individuals.

Analysis of spot urine biomarkers and association with body weight in Japanese elementary schoolchildren

Childhood obesity is rapidly increasing worldwide and is largely the consequence of adoption of unhealthy diets excessive in calories and salt (NaCl) as well as devoid in pivotal micronutrients such as potassium (K) and magnesium (Mg). Education-based programs aiming to encourage healthy food knowledge and behaviors are crucial at a young age, and for this purpose, convenient ways to assess daily dietary intake are warranted. We therefore attempted to evaluate the dietary intake of Okinawan schoolchildren in Japan by analyzing a series of biomarkers in morning spot urine samples and explore whether these biomarkers correlate with body weight and a series of metabolic parameters. We enrolled 98 third-grade elementary schoolchildren in Okinawa, Japan. Morning spot urine samples were collected and analyzed using high-performance liquid chromatography (HPLC) to assess dietary intake. We found that estimated daily NaCl intake was higher in obese/overweight children as compared to healthy-weight children (p = 0.0001). There was also a significant positive correlation between body mass index (BMI) and NaCl intake (Spearman) (ρ = 0.45, p < 0.0001) and a negative correlation between BMI and Mg/Cr (ρ =  -0.27, p = 0.01). Furthermore, Na/K ratio was higher in samples collected on Monday (weekend) as compared to samples collected on Thursday or Friday (weekday) (p < 0.0001).

CONCLUSION

Via the use of morning spot urine analyses, our results show that NaCl intake was associated with obesity, and Mg excretion negatively correlated with BMI in Japanese schoolchildren, highlighting the potential role of these micronutrients in maintaining a healthy body weight.

WHAT IS KNOWN

•Overweight and obesity are largely due to excessive consumption of calories and positively correlated with salt (NaCl) intake. •Spot urine methods are convenient for assessing the nutritional needs and targeting prevention programs in children.

WHAT IS NEW

•Utilizing morning spot urine analyses, estimated NaCl intake is positively correlated and Mg/Cr negatively correlated with BMI in Okinawan schoolchildren. •As estimated via morning spot urine samples, a greater proportion of children likely exceeds the recommended NaCl intake on the weekend as compared to weekday.

Dietary Reference Intakes of sodium for Koreans: focusing on a new DRI component for chronic disease risk reduction

Sodium is a physiologically essential nutrient, but excessive intake is linked to the increased risk of various chronic diseases, particularly cardiovascular. It is, therefore, necessary to accomplish an evidence-based approach and establish the Korean Dietary Reference Intakes (KDRIs) index, to identify both the nutritional adequacy and health effects of sodium. This review presents the rationale for and the process of revising the KDRIs for sodium and, more importantly, establishing the sodium Chronic Disease Risk Reduction Intake (CDRR) level, which is a new specific set of values for chronic disease risk reduction. To establish the 2020 KDRIs for dietary sodium, the committee conducted a systematic literature review of the intake–response relationships between the selected indicators for sodium levels and human chronic diseases. In this review, 43 studies published from January 2014 to December 2018, using databases of PubMed and Web of Science, were finally included for evaluating the risk of bias and strength of evidence (SoE). We determined that SoE of the relationship between dietary sodium and cardiovascular diseases, cerebrovascular disease, and hypertension, was moderate to strong. However, due to insufficient scientific evidence, we were unable to establish the estimated average requirement and the recommended nutrient intake for dietary sodium. Therefore, the adequate intake of sodium for adults was established to be 1,500 mg/day, whereas the CDRR for dietary sodium was established at 2,300 mg/day for adults. Intake goal for dietary sodium established in the 2015 KDRIs instead of the tolerable upper intake level was not presented in the 2020 KDRIs. For the next revision of the KDRIs, there is a requirement to pursue further studies on nutritional adequacy and toxicity of dietary sodium, and their associations with chronic disease endpoint in the Korean population.

Insight Into Differences in Dietary Sodium Adherence Between Men and Women With Heart Failure

BACKGROUND

Men with heart failure are reported to be less adherent to low-sodium diets than women are. One potential reason may be that men consume more food and, consequently, more sodium than women do.

OBJECTIVES

The aims of this study were to compare dietary sodium intake, urine sodium excretion, and sodium density of diet consumed between men and women with heart failure and to determine whether sex moderated the relationship of kilocalories (kcals) consumed with dietary and urine sodium.

METHODS

A total of 223 patients with heart failure (mean age, 62 ± 12 years; 70% men, 46% New York Heart Association class III-IV) completed detailed 4-day food diaries and provided 24-hour urine sodium samples. To account for sodium density of food, dietary sodium and urine sodium were referenced to sodium per 1000 kcal.

RESULTS

On an absolute basis, men consumed 23% more kcals and 28% more sodium than women did; 24-hour sodium excretion was 16% higher in men than in women. There were no differences between men and women when dietary sodium and urinary sodium were referenced to 1000 kcal, indicating they consumed foods with similar sodium density. However, both moderation analyses showed that the dietary sodium intake of men and women with lower kcal intake was similar, whereas men with higher kcal intake consumed more sodium-dense foods than women did.

CONCLUSION

The results suggest that the men with higher sodium intake than women had 2 reasons for nonadherence. They consumed more food and foods with higher sodium density than women did.

Progress on sodium reduction in South Korea

Introduction

High dietary sodium is a leading contributor to hypertension, and hypertension is the leading underlying cause of death globally. There is a robust body of evidence supporting the health benefits of sodium reduction. Sodium intake in South Korea is high, with about half the population consuming >4000 mg/day, twice the recommended upper limit.

Methods

In 2012, South Korea implemented its National Plan to Reduce Sodium Intake, with a goal of reducing population sodium consumption by 20%, to 3900 mg/day, by 2020. The plan included five key components: (1) a consumer awareness campaign designed to change food consumption behaviours; (2) increased availability of low-sodium foods at schools and worksites; (3) increased availability of low-sodium meals in restaurants; (4) voluntary reformulation of processed foods to lower sodium content; and (5) development of low-sodium recipes for food prepared at home. Monitoring and evaluation included tracking sodium intake and sources of dietary sodium using the Korea National Health and Nutrition Examination Survey.

Results

By 2014, South Korea had reduced dietary sodium consumption among adults by 23.7% compared to a survey conducted in 2010 prior to implementation of a nationwide salt reduction campaign that used this comprehensive, multipronged approach. The reductions in sodium intake were accompanied by reductions in population blood pressure and hypertension prevalence. Although causal associations between the sodium reduction programme and reduced sodium intake cannot be made, the declines occurred with the introduction of the programme.

Conclusion

Multicomponent interventions have great potential to reduce population sodium intake. Lessons learnt from South Korea could be applied to other countries and are likely very relevant to other Asian countries with similar food sources and consumption profiles.

Salt added to food and body mass index: A bidirectional Mendelian randomisation study

AIM

This study aimed to determine the causal association between salt added to food and body mass index (BMI) by integrating a summary-level genome-wide association study (GWAS) data.

METHODS

We performed two-sample Mendelian randomisation (MR) analyses using summary statistics of GWAS. Inverse-variance weighted (IVW), maximum likelihood estimation, and random effect model were used to analyse the effect of salt added to food on BMI. A bidirectional MR analysis with BMI as the exposure and salt added to food as the outcome was also performed.

RESULTS

The single nucleotide polymorphisms (SNPs) were selected from the UK Biobank (n = 462 630) and a meta-analysis of 322 154 European-descent individuals. The IVW method estimate indicated that salt added to food was positively associated with BMI (β = 0.1416, SE = 0.0576, P = .0139). Results from maximum likelihood estimation (β = 0.1476, SE = 0.0363, P < .0001) and the random effect model (β = 0.1411, SE = 0.0572, P = .0137) were consistent with the IVW. Bidirectional MR analysis suggested that BMI did not causally affect salt added to food.

CONCLUSION

Our results provided qualitative evidence supporting a causal relationship between salt intake and BMI.

Dietary Sodium Intake is Predicted by Antihypertensive Medication Regimen in Patients With Heart Failure

BACKGROUND

Low-sodium diet adherence is foundational to heart failure (HF) self-management. Altered salt taste perception caused by angiotensin-converting enzyme (ACE) inhibitors commonly prescribed to patients with HF may increase sodium consumption. We hypothesized sodium intake, indicated by dietary sodium density, would be significantly higher among patients with HF prescribed ACE inhibitors compared with those not prescribed the drug.

OBJECTIVE

The aim of this study was to assess the association between prescribed ACE inhibitors and dietary sodium density in patients with HF.

METHODS

We conducted a secondary analysis of baseline data from patients with HF in an observational longitudinal study. Sodium density was derived by dividing averaged daily sodium intake from 4-day food diaries by averaged kilocalories consumed. Medical chart review was conducted to ascertain prescribed medications. Patients were categorized as prescribed and not prescribed an ACE inhibitor. t Tests were conducted to compare sodium intake between groups, and linear regression was conducted to examine whether prescribed ACE inhibitors independently predicted sodium density controlling for age, gender, New York Heart Association class, prescribed diuretics, and β-blockers.

RESULTS

Analyses included 255 patients with HF aged 61 ± 12 years, with 67% male, 44% New York Heart Association class III/IV, and 68% prescribed an ACE inhibitor. Compared with those not prescribed an ACE inhibitor, 13% more sodium per kilocalorie was consumed by patients prescribed an ACE inhibitor. Prescribed ACE inhibitor independently predicted dietary sodium density (β = 0.238, P = .009).

CONCLUSIONS

Sodium intake was higher among patients prescribed ACE inhibitors. Interventions to assist patients with HF with dietary sodium adherence can be informed by assessing medication regimens.

Causal associations between urinary sodium with body mass, shape and composition: a Mendelian randomization study

Observational studies have found associations between urinary sodium (UNa) with obesity, body shape and composition; but the findings may be biased by residual confounding. The objective of this two-sample Mendelian randomization (MR) study was to analyze their causal associations in both sex-combined and sex-specific models. Genome-wide association studies of UNa, body mass index (BMI), BMI-adjusted waist-to-hip ratio (WHR), body fat (BF) percentage and estimated glomerular filtration rate (eGFR) were identified. We initially extracted fifty SNPs associated with UNa at significance level of 5 × 10^–8, but further removed those SNPs with potential horizontal pleiotropy. Univariable and multivariable MR with adjustment for eGFR were performed. Inverse-variance weighted MR was performed as the primary analysis, with MR-Egger methods as sensitivity analysis. The potential bidirectional association between BMI and UNa was investigated. All exposure and outcomes were continuous, and the effect measure was regression coefficients (beta) and their 95% confidence intervals (95% CI). The total sample size was up to 322 154. UNa was causally associated with increased BMI in both men [eGFR-adjusted beta 0.443 (0.163–0.724)] and women [0.594 (0.333–0.855)]. UNa caused BF percentage increase in men [0.622 (0.268–0.976)] and women [0.334 (0.007–0.662)]. UNa significantly elevated BMI-adjusted WHR in men [0.321 (0.094–0.548)], but not in women [0.170 (− 0.052 to 0.391)]. Additionally, we found that BMI causally increased UNa [0.043 (0.023–0.063)]. UNa increased BMI and BF percentage. Salt intake affects male body shape by increasing BMI-adjusted WHR, but showed no effects on female body shape. The bidirectional association between BMI and UNa suggested that salt reduction measures and weight reduction measures should be implemented simultaneously to break the vicious cycle and gain more health benefits.

The association between dietary sodium intake, adiposity and sugar-sweetened beverages in children and adults: a systematic review and meta-analysis

Higher intakes of Na may contribute to weight gain. The primary aim of this systematic review and meta-analysis was to examine the relationship between dietary Na intake and measures of adiposity in children and adults. Given the previous link between Na intake and the consumption of sugar-sweetened beverages (SSB), which are a known risk factor for obesity, a secondary aim examining the relationship between Na intake and SSB consumption was assessed. A systematic literature search identified cross-sectional and longitudinal studies and randomised controlled trials (RCT) which reduced dietary Na (≥3 months). Meta-analysis was performed for outcomes with ≥3 studies. Cross-sectionally higher Na intakes were associated with overweight/obesity in adults (five studies; n 11 067; OR 1·74; 95 % CI 1·43, 2·13) and in children (three studies; n 3625, OR 3·29; 95 % CI 2·25, 4·80), and abdominal obesity (five studies; n 19 744; OR 2·04; 95 % CI 1·72, 2·42) in adults. Overall, associations remained in sensitivity analyses which adjusted for energy. Findings from longitudinal studies were inconsistent. RCT in adults indicated a trend for lower body weight on reduced-Na compared with control diets (fifteen studies; n 5274; -0·29 kg; 95 % CI -0·59, 0·01; P = 0·06); however, it is unclear if energy intakes were also altered on reduced-Na diets. Among children higher Na intakes were associated with higher intake of SSB (four studies, n 10 329, b = 22, 16 and 26 g/d); no studies were retrieved for adults. Overall, there was a lack of high-quality studies retrieved. While cross-sectional evidence indicates Na intake was positively associated with adiposity, these findings have not been clearly confirmed by longitudinal studies or RCT.

Higher Sodium Intake Assessed by 24 Hour Urinary Sodium Excretion Is Associated with Non-Alcoholic Fatty Liver Disease: The PREVEND Cohort Study

A higher sodium intake is conceivably associated with insulin resistant conditions like obesity, but associations of non-alcoholic fatty liver disease (NAFLD) with a higher sodium intake determined by 24 hours (24 h) urine collections are still unclear. Dietary sodium intake was measured by sodium excretion in two complete consecutive 24 h urine collections in 6132 participants of the Prevention of Renal and Vascular End-Stage Disease (PREVEND) cohort. Fatty Liver Index (FLI) ≥60 and Hepatic Steatosis Index (HSI) >36 were used as proxies of suspected NAFLD. 1936 (31.6%) participants had an FLI ≥60, coinciding with the increased prevalence of type 2 diabetes (T2D), metabolic syndrome, hypertension and history of cardiovascular disease. Sodium intake was higher in participants with an FLI ≥60 (163.63 ± 61.81 mmol/24 h vs. 136.76 ± 50.90 mmol/24 h, p < 0.001), with increasing incidence in ascending quartile categories of sodium intake (p < 0.001). Multivariably, an FLI ≥60 was positively associated with a higher sodium intake when taking account for T2D, a positive cardiovascular history, hypertension, alcohol intake, smoking and medication use (odds ratio (OR) 1.54, 95% confidence interval (CI) 1.44–1.64, p < 0.001). Additional adjustment for the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) diminished this association (OR 1.30, 95% CI 1.21–1.41, p < 0.001). HSI >36 showed similar results. Associations remained essentially unaltered after adjustment for body surface area or waist/hip ratio. In conclusion, suspected NAFLD is a feature of higher sodium intake. Insulin resistance-related processes may contribute to the association of NAFLD with sodium intake.

Comparison of 24-h Diet Records, 24-h Urine, and Duplicate Diets for Estimating Dietary Intakes of Potassium, Sodium, and Iodine in Children

Accurately estimating nutrient intake can be challenging, yet it is important for informing policy. This cross-sectional validation study compared the use of three methods for estimating the intake of sodium, potassium, and iodine in children aged 9–11 years in New Zealand. Over the same 24 hour period, participants collected duplicate diets (n = 37), weighed food records (n = 84), and 24 hour urine samples (n = 82). Important differences were found between dietary estimates of sodium, potassium, and iodine using the three methods of dietary assessment, suggesting that different methods of assessment have specific limitations for the measurement of these nutrients in children. Bland Altman plots show relatively wide limits of agreement for all measures and nutrients. These results support the World Health Organization’s (WHOs) recommendations to use urinary assessment to measure population sodium and iodine intake, while dietary assessment appears to be more accurate for estimating potassium intake. Compared to reference values, our results suggest that the children in this study consume inadequate iodine, inadequate potassium, and excess dietary sodium. Public health measures to reduce sodium intake, increase intake of fruit and vegetables, and iodine-rich foods are warranted in New Zealand.

Comparison of 24-hour urine and 24-hour diet recall for estimating dietary sodium intake in populations: A systematic review and meta-analysis

This systematic literature review and meta-analysis examined whether 24-hour diet recall is a valid way to measure mean population sodium intake compared with the gold standard 24-hour urinary assessment. The authors searched electronic databases MEDLINE, Embase, and Scopus using pre-defined terms. Studies were eligible for inclusion if they assessed adult humans in free-living settings, and if they included group means for 24-hour diet recall and 24-hour urinary collection of sodium intake in the same participants. Studies that included populations with an active disease state that might interfere with normal sodium metabolism were excluded. Results of 28 studies are included in the meta-analysis. Overall, 24-hour diet recall underestimated population mean sodium intake by an average of 607 mg per day compared to the 24-hour urine collection. The difference between measures from 24-hour urine and 24-hour diet recall was smaller in studies conducted in high-income countries, in studies where multiple-pass methods of 24-hour diet recall were reported and where urine was validated for completeness. Higher quality studies also reported smaller differences between measures than lower quality studies. Monitoring of population sodium intake with 24-hour urinary excretion remains the most accurate method of assessment. Twenty-four-hour diet recall tends to underestimate intake, although high-quality 24-hour diet recall improves accuracy, and may be used if 24-hour urine is not feasible.

Salt intake among Iranian population: the first national report on salt intake in Iran

OBJECTIVE

In Iran, there has been no national report on salt intake based on laboratory measurements so far. Therefore, this study was conducted to measure salt intake among Iranian population at the national level.

METHODS

In stepwise approach to conduct a surveillance survey 2016, 18 624 Iranian adults (25 years old and above), as a representative sample of Iranian adult population at national and subnational levels, underwent urine sodium measurement and were included in this study. The participants were recruited through a systematic random sampling from 30 provinces of Iran. For each individual, through a computer-assisted interview, a questionnaire on lifestyle risk factors was completed, all anthropometric indices were measured, and data on sodium of spot urine sample for all individuals and 24-h urine sample for a subsample were collected. To estimate the 24-h salt intake, common equations were used.

RESULTS

In total, 97.66% of the population consumed at least 5 g of salt per day. In addition, in 41.20% of the population, the level of salt intake was at least two times higher than the level recommended by the WHO for adults. The mean of salt intake among Iranian population was 9.52 g/day (95% confidence interval: 9.48-9.56).

CONCLUSION

The study showed that the consumption of salt among the Iranian population is higher than the level recommended by WHO. To reduce salt intake, it is necessary to adopt a combination of nationwide policies such as food reformulation and food labelling.

Salt intake and prevalence of overweight/obesity in Japan, China, the United Kingdom, and the United States: the INTERMAP Study

BACKGROUND

Several studies have reported that dietary salt intake may be an independent risk factor for overweight/obesity, but results from previous studies are controversial, reflecting study limitations such as use of a single spot urine or dietary recall to estimate daily salt intake rather than 24-h urine collections, and population samples from only a single country or center.

OBJECTIVE

The aim of this study was to use data from the International Study of Macro-/Micro-nutrients and Blood Pressure (INTERMAP Study) to explore the relation between dietary salt intake estimated from 2 timed 24-h urine collections and body mass index (BMI; in kg/m2) as well as prevalence of overweight/obesity in Japan, China, the United Kingdom, and the United States.

METHODS

Data were from a cross-sectional study of 4680 men and women aged 40-59 y in Japan (n = 1145), China (n = 839), the United Kingdom (n = 501), and the United States (n = 2195). General linear models were used to obtain the regression coefficients (β) of salt intake associated with BMI. Multivariable logistic regression models were used to determine the ORs and 95% CIs of overweight/obesity associated with a 1-g/d higher dietary salt intake.

RESULTS

After adjustment for potential confounding factors including energy intake, salt intake 1 g/d higher was associated with BMI higher by 0.28 in Japan, 0.10 in China, 0.42 in the United Kingdom, and 0.52 in the United States, all P values < 0.001. Salt intake 1 g/d higher was associated with odds of overweight/obesity 21% higher in Japan, 4% higher in China, 29% higher in the United Kingdom, and 24% higher in the United States, all P values < 0.05.

CONCLUSIONS

Salt intake is positively associated with BMI and the prevalence of overweight/obesity in Japan, China, the United Kingdom, and the United States. This association needs to be further confirmed in well-designed prospective studies with repeated dietary and BMI measurements.This trial was registered at clinicaltrials.gov as NCT00005271.

Prevalence and risk determinants of metabolic syndrome in obese worksite workers in hill city of Himachal Pradesh, India

OBJECTIVE

We report prevalence and risk factors of metabolic syndrome (MS) in the obese workforce of organized sector in hill city of Himachal Pradesh (HP), India.

METHODS

The cross-sectional survey study of employees of organized sectors in Shimla city of HP, India, was conducted to collect data of demographics, health behavior, psychosocial factors, anthropometry, blood pressure, and blood chemistry to measure blood glucose and lipid profile in fasting state in 3004 employees using validated tools. Out of 3004 subjects screened, data of 418 subjects with body mass index of ≥30 are analyzed to estimate the prevalence of MS and its risk determinants. The association of demographics, health behavior, and psychosocial factors as the risk determinants were analyzed using multivariable logistic regression modeling.

RESULTS

MS was prevalent in 57.6% [95% confidence interval (CI): 52.8%-62.3%]. The central obesity (odds ratio: 10.6, 95% CI: 2.32-48.4) and consumption of frequent or daily alcohol (odds ratio: 1.94, 95% CI: 1.05-3.59),and extra salt (odds ratio: 3.34, 95% CI: 1.09-10.2) were independent risk factors for MS. The consumption of tobacco, vegetables, sugar-sweetened drinks, physical inactivity, and psychosocial factors had no significant association with MS in obese population.

CONCLUSIONS

MS is highly prevalent among obese employees of organized sector. The consumption of alcohol and extra salt were major behavioral risk factors for MS and therefore have important implications in behavioral modifications for prevention of MS among obese employees in organized sectors.

Paucity of high-quality studies reporting on salt and health outcomes from the science of salt: A regularly updated systematic review of salt and health outcomes (April 2017 to March 2018)

The purpose of this review is to identify, summarize, and critically appraise studies on dietary salt and health outcomes that were published from April 2017 to March 2018. The search strategy was adapted from a previous systematic review on dietary salt and health. Identified studies were screened based on a priori defined criteria to identify publications eligible for detailed critical appraisals. Overall, 6747 citations were identified by the search strategy, and 42 health outcome studies were identified. Three of the 42 studies met the criteria for methodological quality and health outcomes and underwent detailed critical appraisals and commentary. In addition, a systematic review and meta-analysis was critically appraised, although it did not strictly meet our methodological criteria. All four of the studies critically appraised found that sodium reduction improved blood pressure, especially in individuals with hypertension. In addition, sodium reduction reduced albuminuria in patients with stage 1-3 chronic kidney disease. Examination of the time course of blood pressure responses to sodium reduction revealed lowering sodium in the context of an average American diet may not produce maximal blood pressure reductions within a 4-week intervention period. This review provides further evidence of the benefit of sodium reduction for blood pressure lowering and gives insights into the subgroups of the population that may derive the greatest benefit from sodium reduction and the time course required to see benefit. Only three high-quality studies were identified during this 12-month review period, highlighting the critical need for more well-conducted rigorous studies in this area.