Estimation of sodium intake by urinary excretion and dietary records in children and adolescents from Porto Alegre, Brazil: a comparision of two methods

Dietary Sodium Intake and Risk of Cardiovascular Disease: A Systematic Review and Dose-Response Meta-Analysis

Dietary sodium intake has received considerable attention as a potential risk factor of cardiovascular disease. However, evidence on the dose-response association between dietary sodium intake and cardiovascular disease risk is unclear. Embase and PubMed were searched from their inception to 17 August 2020 and studies that examined the association between sodium intake and cardiovascular disease in adolescents were not included in this review. We conducted a meta-analysis to estimate the effect of high sodium intake using a random effects model. The Newcastle-Ottawa Scale assessment was performed. A random-effects dose-response model was used to estimate the linear and nonlinear dose-response relationships. Subgroup analyses and meta-regression were conducted to explain the observed heterogeneity. We identified 36 reports, which included a total of 616,905 participants, and 20 of these reports were also used for a dose-response meta-analysis. Compared with individuals with low sodium intake, individuals with high sodium intake had a higher adjusted risk of cardiovascular disease (Rate ratio: 1.19, 95% confidence intervals = 1.08–1.30). Our findings suggest that there is a significant linear relationship between dietary sodium intake and cardiovascular disease risk. The risk of cardiovascular disease increased up to 6% for every 1 g increase in dietary sodium intake. A low-sodium diet should be encouraged and education regarding reduced sodium intake should be provided.

Sodium and potassium excretion predict increased depression in urban adolescents

This study examined the prospective role of urinary sodium and potassium excretion in depressive symptoms among urban, low-income adolescents, and whether these relationships vary by gender. A total of 84 urban adolescents (mean age 13.36 years; 50% male; 95% African American) self-reported on their depressive symptoms at baseline and 1.5 years later. At baseline, the youth also completed a 12-h (overnight) urine collection at home which was used to measure sodium and potassium excretion. After adjusting for baseline depressive symptoms, age, BMI percentile, and pubertal development, greater sodium excretion and lower potassium excretion predicted more severe depressive symptoms at follow-up, with no significant gender differences. The results suggest that consumption of foods high in sodium and low in potassium contributes to the development of depressive symptoms in early adolescence, and that diet is a modifiable risk factor for adolescent depression. Interventions focusing on diet may improve mental health in urban adolescents.

Reliable Quantification of the Potential for Equations Based on Spot Urine Samples to Estimate Population Salt Intake: Protocol for a Systematic Review and Meta-Analysis

Background

Methods based on spot urine samples (a single sample at one time-point) have been identified as a possible alternative approach to 24-hour urine samples for determining mean population salt intake.

Objective

The aim of this study is to identify a reliable method for estimating mean population salt intake from spot urine samples. This will be done by comparing the performance of existing equations against one other and against estimates derived from 24-hour urine samples. The effects of factors such as ethnicity, sex, age, body mass index, antihypertensive drug use, health status, and timing of spot urine collection will be explored. The capacity of spot urine samples to measure change in salt intake over time will also be determined. Finally, we aim to develop a novel equation (or equations) that performs better than existing equations to estimate mean population salt intake.

Methods

A systematic review and meta-analysis of individual participant data will be conducted. A search has been conducted to identify human studies that report salt (or sodium) excretion based upon 24-hour urine samples and spot urine samples. There were no restrictions on language, study sample size, or characteristics of the study population. MEDLINE via OvidSP (1946-present), Premedline via OvidSP, EMBASE, Global Health via OvidSP (1910-present), and the Cochrane Library were searched, and two reviewers identified eligible studies. The authors of these studies will be invited to contribute data according to a standard format. Individual participant records will be compiled and a series of analyses will be completed to: (1) compare existing equations for estimating 24-hour salt intake from spot urine samples with 24-hour urine samples, and assess the degree of bias according to key demographic and clinical characteristics; (2) assess the reliability of using spot urine samples to measure population changes in salt intake overtime; and (3) develop a novel equation that performs better than existing equations to estimate mean population salt intake.

Results

The search strategy identified 538 records; 100 records were obtained for review in full text and 73 have been confirmed as eligible. In addition, 68 abstracts were identified, some of which may contain data eligible for inclusion. Individual participant data will be requested from the authors of eligible studies.

Conclusions

Many equations for estimating salt intake from spot urine samples have been developed and validated, although most have been studied in very specific settings. This meta-analysis of individual participant data will enable a much broader understanding of the capacity for spot urine samples to estimate population salt intake.

Sodium and potassium intake estimated using two methods in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

CONTEXT AND OBJECTIVE

Sodium and potassium intake from different food sources is an important issue regarding cardiovascular physiology. Epidemiological assessment of the intake of these electrolytes intake is done through food frequency questionnaires or urinary excretion measurements. Our aim was to compare these methods using a sample of Brazilian civil servants.

DESIGN AND SETTING

Cross-sectional baseline evaluation from the Brazilian Longitudinal Study of Adult Health.

METHODS

Sodium and potassium intake was obtained using two methods: a semi-quantitative questionnaire including 114 food items; and overnight 12-hour urinary excretion measurement. Sodium and potassium estimates obtained through the questionnaire were adjusted for energy intake using the residual method. Urinary excretion measurements were considered valid if they met three adequacy criteria: collection time, volume and total creatinine excretion. Mean nutrients were estimated, and Spearman correlations were calculated. Sodium and potassium intake was categorized into quintiles, and weighted kappa coefficients and percentage agreement were calculated. The significance level for all tests was 0.05.

RESULTS

Data from 15,105 participants were analyzed, and significant differences between mean intakes of sodium (questionnaire: 4.5 ± 1.7 g; urine: 4.2 ± 2.1 g) and potassium (questionnaire: 4.7 ± 1.8 g; urine: 2.4 ± 1 g) were found. Weak agreement was found for sodium (K = 0.18) and potassium (K = 0.16). The percentage disagreement between methods ranged from 41.8 to 44.5%, while exact concordance ranged from 22.1% to 23.9%.

CONCLUSIONS

The agreement between the food frequency questionnaire and urinary excretion measurements for assessment of sodium and potassium intakes was modest.

Evaluation of Salt Intake, Urinary Sodium Excretion and Their Relationship to Overhydration in Chronic Kidney Disease Patients

The purpose of this study was to estimate sodium intake in a group of patients with chronic kidney disease (CKD) and to correlate the results with the urinary excretion values of sodium and signs of fluid overload. We included patients with CKD in different stages. Urinary sodium was measured in 24 h urine samples. Body composition monitor (BCM) was used to estimate the hydration status. Sixty patients (38 ± 15 ml/min of GFR) presented 4.14 ± 1.71 g/24 h of urinary sodium excretion. Overhydration was detected in 50% of the patients by the BCM. There was a positive correlation between the measured sodium excretion values and BCM, ICW, ECW and TBW. In conclusion, markers of overhydration evaluated by BCM were positively correlated with urinary sodium excretion.

Consumption and sources of dietary salt in family members in Beijing

In China, few people are aware of the amount and source of their salt intake. We conducted a survey to investigate the consumption and sources of dietary salt using the “one-week salt estimation method” by weighing cooking salt and major salt-containing food, and estimating salt intake during dining out based on established evidence. Nine hundred and three families (1981 adults and 971 children) with students in eight primary or junior high schools in urban and suburban Beijing were recruited. On average, the daily dietary salt intake of family members in Beijing was 11.0 (standard deviation: 6.2) g for children and adolescents (under 18 years old), 15.2 (9.1) g for adults (18 to 59 years old), and 10.2 (4.8) g for senior citizens (60 years old and over), respectively. Overall, 60.5% of dietary salt was consumed at home, and 39.5% consumed outside the home. Approximately 90% of the salt intake came from cooking (household cooking and cafeteria or restaurant cooking), while less than 10% came from processed food. In conclusion, the dietary salt intake in Beijing families far surpassed the recommended amounts by World Health Organization, with both household cooking and dining-out as main sources of salt consumption. More targeted interventions, especially education about major sources of salt and corresponding methods for salt reduction should be taken to reduce the risks associated with a high salt diet.

A pilot study to validate a standardized one-week salt estimation method evaluating salt intake and its sources for family members in China

The objective of this study was to develop a new method named the “one-week salt estimation method” that could estimate an individual’s salt intake and the sources of salt in the diet, and to evaluate this new method with a 24-h urine collection. The new method estimates salt intake from: (1) household cooking by weighing the family salt container and other high-salt condiments or sauces at the beginning and end of a week; (2) processed food according to established China food composition figures; and (3) cafeteria or restaurant meals using the results of previous studies. Consumption of salt additives and major salt contained foods and salt intake related eating habits were collected using a structured simple seven-day questionnaire. In order to validate the method, we studied 37 individuals from 11 families using the new method and 26 of these participants collected seven concurrent 24-h urine samples. The average salt intake for the 26 participants was 15.6 ± 5.5 g/person/day (mean ± standard deviation) by the 24-h urine collection and 13.7 ± 6.5 g/person/day by the new method. The difference was 1.8 ± 4.2 g/day/person (p = 0.037). The Pearson correlation coefficient was 0.762 (p < 0.001) and the partial correlation coefficient was 0.771 (p < 0.001) when adjusted for family code. Bland-Altman Plot showed the average of the difference between the two methods was −1.83, with 95% limits of −10.1 to 6.5 g/person/day. The new method showed that 43.7% of salt intake came from household cooking (33.5% from cooking salt, 10.2% from other condiments and sauces), 12.9% from processed food, and 43.4% from eating out. In conclusion, despite its limitations of underestimating salt intake, the “one-week salt estimation method” is easier for people to implement and is likely to provide useful information that highlights the excessively high intake of salt and its sources, and in turn is helpful in guiding dietary salt reduction.

Risk factors for high blood pressure in low income children aged 3-4 years

This study aimed to evaluate the effect of dietary sodium intake on blood pressure among low income children aged 3-4 years. Data were collected during a randomized trial conducted in São Leopoldo, Brazil, with 500 mother-child pairs recruited from the maternity ward of a local hospital. Breastfeeding data were obtained during the children's first year of life. At 3 to 4 years of age, children's anthropometric, dietary, and blood pressure assessments were obtained. Sodium intake was estimated from two multiple-pass 24-h dietary recalls. Systolic blood pressure > 90th percentile for age, sex, and height was classified as high systolic blood pressure, according to the population-based percentiles provided by the Task Force on Hypertension Control in Children and Adolescents. Blood pressure data were obtained from 331 children at 3 to 4 years. The mean value of systolic blood pressure was 91.31 mmHg (SD = 8.30 mmHg) and 5.2% (n = 17) presented high systolic blood pressure. The results of the multivariable analyses showed that children who consumed more than 1,200 mg of sodium/day and with waist-to-height ratio higher than 0.5 presented, respectively, 3.32 (95%CI 0.98-11.22) and 8.81 (95%CI 2.13-36.31) greater risk of having high systolic blood pressure. Exclusive breastfeeding, child overweight and change in body mass index z score during the first year of life were not associated with the outcome.

CONCLUSIONS

The results of this study suggest that at preschool age sodium intake and high waist-to-height ratio are risk factors for high systolic blood pressure.

Estimativa de consumo de sódio pela população brasileira, 2008-2009

OBJETIVO: Atualizar estimativas sobre consumo de sódio no Brasil.MÉTODOS: Foram utilizados dados da Pesquisa de Orçamentos Familiares 2008-2009. Realizou-se a conversão em nutrientes dos registros de aquisição de alimentos dos domicílios brasileiros por meio de tabelas de composição de alimentos. Foram calculadas a disponibilidade média de sódio/pessoa/dia e a disponibilidade média ajustada para um consumo energético diário de 2.000 kcal. Calculou-se a contribuição de grupos de alimentos selecionados para o total de sódio disponível para consumo no domicílio e comparou-se com aqueles da Pesquisa de Orçamentos Familiares 2002-2003.RESULTADOS: A quantidade diária de sódio disponível para consumo nos domicílios brasileiros foi de 4,7 g para ingestão diária de 2.000 kcal, mantendo-se mais de duas vezes superior ao limite recomendado de ingestão desse nutriente. A maior parte do sódio disponível para consumo provém do sal de cozinha e de condimentos à base de sal (74,4%), mas a fração proveniente de alimentos processados com adição de sal aumentou linear e intensamente com o poder aquisitivo domiciliar (12,3% do total de sódio no quinto inferior da distribuição da renda por pessoa e 27,0% no quinto superior). Observou-se redução na contribuição de sal e condimentos à base de sal (76,2% para 74,4%) e dos alimentos in natura ou processados sem adição de sal (6,6% para 4,8%) e aumento dos alimentos processados com adição de sal (15,8% para 18,9%) e dos pratos prontos (1,4% para 1,6%) na comparação com a Pesquisa de Orçamentos Familiares 2002-2003.CONCLUSÕES: O consumo de sódio no Brasil mantém-se em níveis acima da recomendação máxima para esse nutriente em todas as macrorregiões e classes de renda brasileiras. Observou-se estabilidade na disponibilidade domiciliar total de sódio e aumento na fração proveniente dos alimentos processados com adição de sal e dos pratos prontos, na comparação de 2008-2009 com 2002-2003.

Twenty-four-hour urinary sodium excretion and postural orthostatic tachycardia syndrome

OBJECTIVE

To investigate whether 24-hour urinary sodium excretion could be an indicator of the effectiveness of salt supplementation in children with postural orthostatic tachycardia syndrome (POTS).

STUDY DESIGN

The patient group comprised 30 children with POTS, and the control group comprised 10 healthy children. Serum sodium and 24-hour urinary sodium excretion were measured in all children, and the relationship between 24-hour urinary sodium and symptom severity was analyzed in the 30 patients. At 1 month after initiation of salt supplementation, the receiver operating characteristic curve was used to explore the probability of correctly discriminating responders to salt supplementation from nonresponders using 24-hour urinary sodium excretion as an indicator.

RESULTS

Patients with POTS had lower 24-hour urinary sodium excretion than controls (P = .022). Symptom severity was negatively correlated with 24-hour urinary sodium excretion (OR, -0.754; P = .000). The receiver operating characteristic curve demonstrated a sensitivity of 76.9% and specificity of 93% for correct prediction of responders and nonresponders to salt supplementation when a 24-hour urinary sodium excretion of 124 mmol/24 hours was used as the cutoff value.

CONCLUSION

Our results indicate that 24-hour sodium excretion of <124 mmol/24 hours is an indicator of the effectiveness of salt supplementation in children and adolescents with POTS.

Sources of variation in energy and nutrient intakes among children from six to thirty months old in a population-based study

The objective of this article was to describe and analyze sources of variation in the dietary intakes of children aged 6 to 30 months. The data was obtained from two 24-hour recall surveys of a sample of 383 children of both sexes in the metropolitan region of Rio de Janeiro, Brazil. Age and the food insecurity scale, which was used as a proxy to characterize socioeconomic differences, were considered. The analysis was based on food groups. The ratio of the coefficients' variation was calculated, and the crude and de-attenuated relative means for energy and macro- and micronutrients were estimated. In addition, the number of 24-hour recall replications was also estimated. Age and food insecurity had significant impacts on the average number of servings of food groups. The coefficients of variation ratios for most nutrients were < 1, except for vitamin C and for children in the younger age group. The number of 24-hour recall required ranged from 1 to 6 days and was higher for vitamin C.

[Estimated sodium intake by the Brazilian population, 2002-2003]

OBJECTIVE

To estimate the magnitude and distribution of sodium intake in Brazil and to identify major dietary sources contributing to this intake.

METHODS

Estimates were based on data from a Brazilian household budget survey carried between July 2002 and June 2003. A total of 969,989 food purchase records from a probabilistic sample of 48,470 households located in 3,984 census tracts across the country were analyzed. Purchase records were converted into nutrients using food composition charts. Mean sodium availability per person per day and mean adjusted availability considering a 2,000 kcal daily energy intake were calculated, as well as the contribution of selected food groups to total household sodium availability. Estimates are presented according to geographical region, urban or rural status of the household, and income stratum.

RESULTS

Mean daily sodium availability in Brazilian households was 4.5 g per person (or 4.7 g considering a daily calorie intake of 2,000 kcal), thus exceeding by more than two times the recommended levels of intake for this nutrient. Although most of the sodium available for intake across all income strata was derived from kitchen salt or salt-based condiments (76.2%), the fraction derived from processed foods with added salt showed a strong linear increase as household purchasing power increased, representing 9.7% of total sodium intake in the lower quintile of the per capita income distribution and 25.0% in the upper quintile.

CONCLUSIONS

Results indicate that sodium intake in Brazil widely exceeds the maximum recommended intake level for this nutrient in all of the country's macro regions and across all income strata.