Cross-Sectional Study of 24-Hour Urinary Electrolyte Excretion and Associated Health Outcomes in a Convenience Sample of Australian Primary Schoolchildren: The Salt and Other Nutrients in Children (SONIC) Study Protocol

Dietary Approaches to Stop Hypertension (DASH) dietary pattern is not associated with blood pressure in a cross-sectional sample of Australian primary schoolchildren

PURPOSE

The beneficial effects of the Dietary Approaches to Stop Hypertension (DASH) to reduce blood pressure among adults are well established. However, whether this dietary pattern is also relevant for the control of blood pressure in children remains unknown. Therefore, this study aimed to evaluate adherence to the DASH dietary pattern and examine its association with blood pressure among Australian primary schoolchildren.

METHOD

Cross-sectional data from 658 Australian children aged 8-12 years participating in the Salt and Other Nutrients In Children (SONIC) study were analyzed. One 24-hour diet recall was used to assess dietary intake. Systolic and diastolic blood pressure were measured with a digital automatic blood pressure machine. To assess adherence to the DASH dietary pattern a total DASH score (0-90) was created based on nine nutrient targets (protein, saturated fat, total fat, cholesterol, total fiber, sodium, potassium, magnesium, calcium). Multiple linear regression models were used to examine the association between the DASH score and blood pressure.

RESULTS

The mean total DASH score was 53.1 (SD 10.4) and was significantly different between boys (52.3) and girls (54.0) (p = 0.013). After controlling for covariates, no association between total DASH score and systolic or diastolic blood pressure was found.

CONCLUSION

Adherence to the DASH dietary pattern was moderate and there was no association between the DASH dietary pattern and blood pressure among Australian children aged 8-12 years.

Evaluation of a state-wide intervention on salt intake in primary schoolchildren living in Victoria, Australia

OBJECTIVE

In 2015, the Victorian Salt Reduction Partnership launched a 4-year multifaceted salt reduction intervention designed to reduce salt intake by 1 g/d in children and adults living in Victoria, Australia. Child-relevant intervention strategies included a consumer awareness campaign targeting parents and food industry engagement seeking to reduce salt levels in processed foods. This study aimed to assess trends in salt intake, dietary sources of salt and discretionary salt use in primary schoolchildren pre- and post-delivery of the intervention.

DESIGN

Repeated cross-sectional surveys were completed at baseline (2010-2013) and follow-up (2018-2019). Salt intake was measured via 24-h urinary Na excretion, discretionary salt use behaviours by self-report and sources of salt by 24-h dietary recall. Data were analysed with multivariable-adjusted regression models.

SETTING

Victoria, Australia.

PARTICIPANTS

Children aged 4-12 years.

RESULTS

Complete 24-h urine samples were collected from 666 children at baseline and 161 at follow-up. Mean salt intake remained unchanged from baseline (6·0; se 0·1 g/d) to follow-up (6·1; 0·4 g/d) (P = 0·36), and there were no clear differences in the food sources of salt and at both time points approximately 70 % of children exceeded Na intake recommendations. At follow-up, 14 % more parents (P = 0·001) reported adding salt during cooking, but child use of table salt and inclusion of a saltshaker on the table remained unchanged.

CONCLUSION

These findings show no beneficial effect of the Victorian Salt Reduction Partnership intervention on children's salt intake. More intensive, sustained and coordinated efforts between state and federal stakeholders are required.

Estimated 24-Hour urinary sodium and potassium excretion in adults in the Northwest Region of Morocco, 2017

BACKGROUND

Excessive sodium (Na) and insufficient potassium (K) intake contribute to a high risk of cardiovascular events. Morocco lacks data on actual Na and K intake in adults. We estimated mean Na and K intake in a Moroccan population of adults residing in the Northwest region using 24-h urinary excretion and examined their association with blood pressure (BP).

METHODS

A total of 371 adults from this region, who were recruited for the STEPs Survey Morocco 2017, completed demographic, anthropometric as well as BP data and provided a valid 24-h urine collection according to the standard World Health Organization (WHO) protocol. Multiple Linear Regression analysis was used to examine the association between 24-h urinary sodium (24-hUNa) and 24-h potassium excretion (24-hUK) with BP.

RESULTS

Mean Na excretion was 2794 mg/day and mean K excretion was 1898 mg/day. Overall, only 114 (30.7%) adults met the WHO recommendation for Na intake (< 2000 mg/d) and 31 (8.4%) met the adequate level for K intake (⩾3510 mg/d). There was no association between 24-hUNa and 24-hUK with BP (P > 0.05 for all).

CONCLUSION

Na intake was higher and K intake was lower than WHO recommendations in the study population. There was no association between estimated Na and K intake levels with BP in this population.

Evaluation of a Salt-Reduction Consumer Awareness Campaign Targeted at Parents Residing in the State of Victoria, Australia

From 2015 to 2020 a state-wide salt-reduction initiative was launched in Victoria, Australia, including an awareness campaign focused on parents with children <18 years of age. To evaluate the impact of the campaign on salt-related knowledge, attitudes and behaviors (KABs) we have assessed trends in salt-related KAB pre- and post-delivery of the campaign in parents, as well as within the wider adult population. Cross-sectional surveys of adults aged 18-65 years were undertaken pre- (2015: n = 821 parents; n = 1527 general sample) and post-campaign (2019: n = 935 parents; n = 1747 general sample). KABs were assessed via an online survey. Data were analyzed with regression models and adjusted for covariates. Among parents, around one-quarter of salt-related KABs shifted in a positive direction, but changes were small: there was a 6% (95% CI 2, 11%) increase in the percentage who knew the main source of salt in the diet and reductions in the percentage who reported placing a salt shaker on the table (-8% (95%CI -12, -3)) and that their child added salt at the table (-5% (95% -9, -0.2)). Among the wider adult sample, even fewer shifts in KAB were observed, with some behaviors worsening at follow-up. These findings indicate that this consumer awareness campaign had minimum impact.

Agreement between 24-hour urine and 24-hour food recall in measuring salt intake in primary school children in Australia

Background

Monitoring salt consumption in children is essential for informing and implementing public health interventions to reduce children’s salt intake. However, collection of 24-hour urines, considered as the most reliable approach, can be especially challenging to school children. This study aimed to assess the agreement between 24-hour urine (24hrU) and 24-hour food recall (24hrFR) in: (1) estimating salt intake in children; (2) classifying salt intakes above the recommended upper level set for children, and; (3) estimating change in mean salt intake over time.

Methods

This study utilised data from two cross-sectional surveys of school children aged 8 to 12 years living in the state of Victoria, Australia. A single 24hrU and 24hrFR were collected from each participant. Suspected inaccurate urine collections and implausible energy intakes were excluded based on pre-defined criteria. The agreement between the two methods was assessed using Bland-Altman methodology, the intraclass correlation coefficient (ICC), and the kappa statistic. The difference between the measured change in salt intake over time using 24hrU and 24hrFR was derived using mixed effects linear regression analysis.

Results

A total of 588 participants provided a 24hrU and 24hrFR. Overall, there was no meaningful difference in mean estimated salt intake between the two methods (− 0.2 g/day, 95% CI − 0.5 to 0.1). The Bland-Altman plot showed wide 95% limits of agreement (− 7.2 to 6.8). The ICC between the two methods was 0.13 (95% CI 0.05 to 0.21). There was poor interrater reliability in terms of classifying salt intake above the recommended upper level for children, with an observed agreement of 63% and kappa statistic of 0.11. The change in mean salt intake over time was 0.2 g/day (− 0.4 to 0.7) based on 24hrU, and 0.5 g/day (− 0.0 to 1.1) based on 24hrFR, with a difference-in-differences of 0.4 g/day (− 0.3 to 1.1).

Conclusions

24hrFR appears to provide a reasonable estimate of mean salt intake as measured by 24hrU in Australian school children. However, similar to previous observations in adults, and of studies exploring other alternative methods for estimating salt intake, 24hrFR is a poor predictor of individual-level salt intake in children.

Dual-mode ion-selective electrodes and distance-based microfluidic device for detection of multiple urinary electrolytes

Here, we developed a microfluidic paper device by combining ion-selective electrodes (ISE) and a distance-based paper device (dPAD) for simultaneous potentiometric and colorimetric detection of urine electrolytes including K+, Na+ and Cl−.

Dietary Sodium and Potassium Intake in Hungarian Elderly: Results from the Cross-Sectional Biomarker2019 Survey

High sodium intake and inadequate potassium intake are associated with high blood pressure. The elderly are more salt sensitive than other age groups, yet a reliable estimate of the dietary sodium and potassium intake of this age group in Hungary is unavailable. The study aimed to estimate the sodium and potassium intakes in the Hungarian elderly from 24 h urine sodium and potassium excretion. In this cross-sectional study, participants were selected from patients of general practitioners practicing in western Hungary. The participants comprised 99 men and 90 women (mean age 67.1 (SD 5.4] years) who participated in the Biomarker2019 survey and returned a complete 24 h urine collection. We assessed dietary sodium and potassium by determining 24 h urinary sodium and potassium excretions and 3-day dietary records. The mean urinary sodium was 188.8 (73.5) mmoL/day, which is equivalent to 11.0 g of salt/day; and the mean urinary potassium was 65.8 (24.3) mmoL/day, which is equivalent to 3.03 g of potassium/day, after adjusting for non-urinary potassium losses. Only 7% of the subjects met the World Health Organization's recommended target of less than 5 g of salt/day, and 33% consumed at least the recommended potassium amount of 3.5 g/day, based on the estimates from 24 h urine excretion. For most elderly, sodium intake exceeds, and potassium does not reach, dietary recommendations. The results underline the need to intensify salt reduction efforts in Hungary.

Food sources of iodine in schoolchildren and relationship with 24-h urinary iodine excretion in Victoria, Australia

Dietary recalls have been used previously to identify food sources of iodine in Australian schoolchildren. Dietary assessment can provide information on the relative contributions of individual food groups which can be related to a robust objective measure of daily intake (24-h urinary iodine excretion (UIE)). In Australia, the government has mandated the use of iodised salt in breadmaking to address iodine deficiency. The aim of this study was to determine the dietary intake and food sources of iodine to assess their contribution to iodine excretion (UIE) in a sample of Australian schoolchildren. In 2011-2013, UIE was assessed using a single 24-h urine sample and dietary intake was assessed using one 24-h dietary recall in a convenience sample of primary schoolchildren from schools in Victoria, Australia. Of the 454 children with a valid recall and urine sample, 55 % were male (average age 10·1 (1·3 (sd) years). Mean UIE and dietary iodine intake were 108 (sd 54) and 172 (sd 74) μg/d, respectively. Dietary assessment indicated that bread and milk were the main food sources of iodine, contributing 27 and 25 %, respectively, to dietary iodine. Milk but not bread intake was positively associated with UIE. Multiple regression (adjusted for school cluster, age and sex) indicated that for every 100 g increase in milk consumption, there was a 3 μg/d increase in UIE (β = 4·0 (se 0·9), P < 0·001). In conclusion, both bread and milk were important contributors to dietary iodine intake; however, consumption of bread was not associated with daily iodine excretion in this group of Australian schoolchildren.

Salt-Related Knowledge, Attitudes and Behaviors (KABs) among Victorian Adults Following 22-Months of a Consumer Awareness Campaign

The Australian population consumes more salt than recommended and this increases the risk of raised blood pressure and cardiovascular disease. In 2015, a state-wide initiative was launched in the Australian state of Victoria to reduce population salt intake. This study examines whether salt-related knowledge, attitudes and behaviors (KABs) of Victorian adults changed following the first 22 months of a consumer awareness campaign targeting parents. Repeated cross-sectional surveys of adults (18–65 years) recruited from research panels. Analyses were weighted to reflect the Victorian population. In both surveys mean age of participants (1584 in 2015 and 2141 in 2018) was 41 years, and 51% were female. This includes 554 parents/caregivers in 2015 and 799 in 2018. Most indicators of KAB remained unchanged. Among parents/caregivers the percentage who agreed limiting salt in their child’s diet was important increased by 8% (p = 0.001), and there was a 10% reduction in the percentage who reported placing a saltshaker on the table and a 9% reduction in those who reported their child added salt at the table (both p < 0.001). Some small adverse effects on other indicators were also observed. During the first 22 months of a salt reduction consumer awareness campaign, there were limited changes in KAB overall, however the target audience reported positive changes regarding their children, which aligned with the campaign messages.

The association of parents' behaviors related to salt with 24 h urinary sodium excretion of their children: A Spanish cross-sectional study

BACKGROUND

Sodium intake is excessive among Spanish children, but the salt use behaviors of parents and children are unknown. This study aims to determine behaviors related to salt intake in both schoolchildren and parents and the relationship between parental behaviors and 24 h urinary sodium excretion (UNa-24h) in children.

SUBJECTS AND METHODS

A convenience sample was taken from a cross-sectional analysis. Parents completed a self-reported questionnaire about their behaviors related to salt, and their responses were compared with the UNa-24h of their own children. The median test was used to identify differences in UNa-24h according to behaviors. Logistic regression was used to assess the relationship between the behaviors of parents and high sodium excretion in the children and the risk of children's use of table salt, adjusting for age, sex, and BMI. Multinomial logistic regression models, adjusted by the covariates, were used to study the children's salt preferences.

RESULTS

A total of 329 schoolchildren from different Spanish provinces were included in the study (mean age: 9.0 ± 1.2 years, 157 girls). The majority of families (parents mean age: 42.0 ± 5.2 years) reported adding salt to food during cooking (92%), and 59% of them never looked at the sodium content on food labels. However, none of these behaviors were related to UNa-24h (p > 0.05). The use of iodized salt (53%), the presence of a salt shaker on the table (6%), and the use of table salt by fathers (57%), mothers (52%) or children (17%) increased the odds (p < 0.05) of children having a higher UNa-24h. Checking sodium content on food labels and the use of table salt by the children or father was associated with a lower preference for salty foods (p < 0.05).

CONCLUSIONS

It is important to make parents aware of the relationship between their behaviors regarding the use of discretionary salt and their children's sodium intake. Our data suggest that salt-specific education programs on how to reduce salt both in-home and outside the home should be implemented to improve behavior skills related to salt consumption in parents and children.

Salt Preference and Ability to Discriminate between Salt Content of Two Commercially Available Products of Australian Primary Schoolchildren

Australian children consume too much salt, primarily from processed foods where salt is often used to enhance flavour. Few studies have assessed children's salt preference in commercially available foods. This study aims to assess (1) children's preference and ability to discriminate between salt levels in two commercially available foods and (2) if preference or ability to discriminate between salt levels changes after an education program. Chips and corn flakes were tasted at three levels of salt concentration. Children ranked which they liked best (preference) and which was saltiest (ability to discriminate). The proportion of children across categorical responses was assessed (Chi squared and McNemar's test) together with changes in preference and ability to discriminate between salt levels from timepoint 1 (T1) to timepoint 2 (T2). Ninety-two children (57% female, mean age 9.1 years (SD 0.8)) participated. At T1 approximately one-half and two-thirds of children preferred the highest salt chip and cornflake, respectively, (both p < 0.05). Fifty-seven percent and 63% of children identified the highest level of salt in chips and cornflakes as the saltiest, respectively. Preference and ability to discriminate between salt levels were unchanged between timepoints. Results support product reformulation to decrease salt content of foods provided to children.

Effects of arm swing exercise training on cardiac autonomic modulation, cardiovascular risk factors, and electrolytes in persons aged 60-80 years with prehypertension: A randomized controlled trial

Background/Objective

This study aimed to investigate the effect and carry-over effect of arm swing exercise (ASE) training on cardiac autonomic modulation, cardiovascular risk factors, and blood electrolytes in older persons with prehypertension.

Methods

Subjects were 50 individuals with prehypertension (aged 66.90 ± 5.50 yr, body mass index 23.84 ± 3.65 kg/m²). They were randomly assigned into ASE group and control group. Subjects in the ASE group underwent an ASE training program for 3 months at a frequency of 30 min/day, 3 days/week. Subjects in the control group maintained their daily routine activities minus regular exercise. Blood pressure, heart rate variability (HRV), cardiovascular risk factors including blood glucose, lipid profile, high-sensitive C-reactive protein (hsCRP), and electrolytes were evaluated on 3 occasions: before and after the 3-month intervention, and 1 month after intervention ended.

Results

Following the 3-month intervention, systolic blood pressure (SBP) and serum hsCRP concentration were significantly lower, while serum high-density lipoprotein (HDL)-cholesterol, potassium (K⁺), magnesium (Mg²⁺) concentrations, standard deviation of normal R-R intervals (RMSSD) and high frequency (HF) power values were higher in the ASE group when compared with the control group (p < 0.05). At the 1-month follow-up interval, SBP and serum hsCRP concentration remained lower while serum HDL-cholesterol and K⁺ concentrations remained higher in the ASE group as compared to the control group (p < 0.05).

Conclusion

ASE training decreased SBP and serum hsCRP concentration, increased serum HDL-cholesterol, K⁺, and Mg²⁺ concentrations and increased RMSSD and HF power values in older persons with prehypertension. In addition, there were carry-over effects of ASE training i.e. decreased SBP and serum hsCRP concentration as well as increased serum HDL-cholesterol and K⁺ concentrations.

Urinary sodium is positively associated with urinary free cortisol and total cortisol metabolites in a cross-sectional sample of Australian schoolchildren aged 5–12 years and their mothers

High Na intake and chronically elevated cortisol levels are independently associated with the development of chronic diseases. In adults, high Na intake is associated with high levels of urinary cortisol. We aimed to determine the association between urinary Na and K and urinary cortisol in a cross-sectional sample of Australian schoolchildren and their mothers. Participants were a sample of Australian children (n 120) and their mothers (n 100) recruited through primary schools. We assessed Na, K, free cortisol and cortisol metabolites in one 24 h urine collection. Associations between 24 h urinary electrolytes and 24 h urinary cortisol were assessed using multilevel mixed-effects linear regression models. In children, urinary Na was positively associated with urinary free cortisol (β=0·31, 95 % CI 0·19, 0·44) and urinary cortisol metabolites (β=0·006, 95 % CI 0·002, 0·010). Positive associations were also observed between urinary K and urinary free cortisol (β=0·65, 95 % CI 0·23, 1·07) and urinary cortisol metabolites (β=0·02, 95 % CI 0·03, 0·031). In mothers, urinary Na was positively associated with urinary free cortisol (β=0·23, 95 % CI 0·01, 0·50) and urinary cortisol metabolites (β=0·008, 95 % CI 0·0007, 0·016). Our findings show that daily Na and K intake were positively associated with cortisol production in children and their mothers. Investigation of the mechanisms involved and the potential impact of Na reduction on cortisol levels in these populations is warranted.

Measuring Children's Sodium and Potassium Intakes in NZ: A Pilot Study

Low sodium and high potassium intakes in childhood protect against rises in blood pressure (BP) and risk of cardiovascular disease (CVD) later in life. Our aim was to pilot methods for collection of 24-h urine samples (gold standard) and diet recalls to assess sodium and potassium intakes and their food sources in 30 children aged 8–11 years at one New Zealand primary school. A diverse sample (n = 27) was recruited over a two-week period. All children provided a urine sample (71% complete) and interviewer-assisted 24-h diet recall (Intake24 software). Median (range) sodium intake was 2191 (1087 to 4786) mg/day (salt equivalent 5.5 g), potassium intake was 1776 (800–2981) mg/day, BP was 105 (84–129)/62 (53–89) mmHg, and sodium to potassium molar ratio was 2.0 (1.1–4.8). Frequent use of discretionary salt was uncommon. Major food sources of sodium were bread, pies and pastries, and bread and pasta-based dishes, and potassium were sauces and condiments, dairy products, and non-alcoholic beverages. Most participants provided adequate data and enjoyed taking part. A larger survey is warranted to confirm findings and inform a potential intervention(s). Small improvements to study procedures and resources should improve completeness of urine samples and quality of 24-h diet recall data.

Assessment of Sodium and Potassium Intakes in Children Aged 6 to 18 Years by 24 h Urinary Excretion in City of Rabat, Morocco

Background

The incidence of noncommunicable diseases (NCDs) has greatly increased, mainly due to high level of dietary sodium. Thus, reduction of sodium intake in population has been recognized as one of the most cost-effective strategies to reduce NCDs. The aim of this study was to estimate sodium and potassium consumption in a sample of Moroccan children as a baseline study to implement national strategy for salt intake reduction.

Methods

The study was conducted on 131 children aged 6-18 years recruited from Rabat and its region. Sodium excretion and potassium excretion were measured on 24 h urinary collection, and the creatinine excretion was used to validate completeness of urine collections.

Results

The average of urinary sodium was 2235.3 ± 823.2 mg/day, and 50% of children consume more than 2 g/d of sodium (equivalent to 5 g/day of salt), recommended by the WHO. However, daily urinary excretion of potassium was 1431 ± 636.5 mg/day, and 75% of children consume less than adequate intake. Sodium consumption increased significantly with age. Of particular interest, 46.7% of children aged 6-8 years and 49.3% of children aged 9-13 years consume more than the corresponding upper limits.

Conclusions

Children have high sodium and low potassium status. There is evidence of the urgent need to implement a strategy for reduction of dietary sodium intake in Morocco.

Digital Education to Limit Salt in the Home (DELISH) Program Improves Knowledge, Self-Efficacy, and Behaviors Among Children

OBJECTIVE

To determine the efficacy of a Web-based salt reduction program on children's salt-related knowledge, attitudes, and behaviors (KABs), self-efficacy, and intake of dietary salt.

DESIGN

Pretest and posttest. An online survey determined KABs and self-efficacy and a 24-hour urine collection revealed salt intake.

SETTING

Victoria, Australia.

PARTICIPANTS

Child-parent dyads (n = 102) recruited from 5 government schools.

INTERVENTION

A 5-week behavior-based education program delivered via weekly online interactive education sessions.

MAIN OUTCOME MEASURES

Change in KABs, self-efficacy, and daily salt intake.

ANALYSIS

Changes in outcomes were assessed using McNemar test, paired t test, and Cohen's δ (CD).

RESULTS

A total of 83 children participated (mean age, 9.2 years [SD, 0.8 years]; 59% girls); 35% to 76% of children viewed weekly education session. Children with complete survey data (n = 75) had improved scores for salt-related knowledge (+3.6 ± 0.4 points; P < .001; CD: 1.16), behaviors (+1.3 ± 0.1 points; P < .001; CD: 1.08), and self-efficacy (+0.9 ± 0.2 points; P < .001; CD: 0.64), but not attitude. Children with valid urine collections (n = 51) showed no change in salt intake.

CONCLUSIONS AND IMPLICATIONS

Participation resulted in improvement of salt related knowledge, self-efficacy and behavior. Further research is required to confirm these results using a more robust study design which includes a control group. In addition, the long term impact on children's salt intakes of comparable education programs needs to be assessed.

Urinary Excretion of Sodium, Nitrogen, and Sugar Amounts Are Valid Biomarkers of Dietary Sodium, Protein, and High Sugar Intake in Nonobese Adolescents

Background: Objective indicators of dietary intake (e.g., biomarkers) are needed to overcome the limitations of self-reported dietary intake assessment methods in adolescents. To our knowledge, no controlled feeding studies to date have evaluated the validity of urinary sodium, nitrogen, or sugar excretion as dietary biomarkers in adolescents.Objective: This investigation aimed to evaluate the validity of urinary sodium, nitrogen, and total sugars (TS) excretion as biomarkers for sodium, protein, and added sugars (AS) intake in nonobese adolescents.Methods: In a crossover controlled feeding study design, 33 adolescents [12-18 y of age, 47 ± 25th percentile (mean ± SD) of body mass index (BMI; in kg/m²) for age] consumed 5% AS [low added sugars (LAS)] and 25% AS [high added sugars (HAS)] isocaloric, macronutrient-matched (55% carbohydrate, 30% fat, and 15% protein) diets for 7 d each, in a randomly assigned order, with a 4-wk washout period between diets. On the final 2 d of each diet period, 24-h urine samples were collected. Thirty-two adolescents completed all measurements (97% retention).Results: Urinary sodium was not different from the expected 90% recovery (mean ± SD: 88% ± 18%, P = 0.50). Urinary nitrogen was correlated with protein intake (r = 0.69, P < 0.001), although it was below the 80% expected recovery (62% ± 7%, P < 0.001). Urinary TS values were correlated with AS intake during the HAS diet (r = 0.77, P < 0.001) and had a higher R² value of 0.28 than did AS intake (R² = 0.36). TS excretion differed between LAS (0.226 ± 0.09 mg/d) and HAS (0.365 ± 0.16 mg/d) feeding periods (P < 0.001).Conclusions: Urinary sodium appears to be a valid biomarker for sodium intake in nonobese adolescents. Urinary nitrogen is associated with protein intake, but nitrogen excretion rates were less than previously reported for adults, possibly owing to adolescent growth rates. TS excretion reflects AS at 25% AS intake and was responsive to the change in AS intake. Thus, urinary biomarkers are promising objective indicators of dietary intake in adolescents, although larger-scale feeding trials are needed to confirm these findings. This trial was registered at clinicaltrials.gov as NCT02455388.

Dietary intake and sources of sodium and potassium among Australian schoolchildren: results from the cross-sectional Salt and Other Nutrients in Children (SONIC) study

OBJECTIVES

To examine sodium and potassium urinary excretion by socioeconomic status (SES), discretionary salt use habits and dietary sources of sodium and potassium in a sample of Australian schoolchildren.

DESIGN

Cross-sectional study.

SETTING

Primary schools located in Victoria, Australia.

PARTICIPANTS

666 of 780 children aged 4-12 years who participated in the Salt and Other Nutrients in Children study returned a complete 24-hour urine collection.

PRIMARY AND SECONDARY OUTCOME MEASURES

24-hour urine collection for the measurement of sodium and potassium excretion and 24-hour dietary recall for the assessment of food sources. Parent and child reported use of discretionary salt. SES defined by parental highest level of education.

RESULTS

Participants were 9.3 years (95% CI 9.0 to 9.6) of age and 55% were boys. Mean urinary sodium and potassium excretion was 103 (95% CI 99 to 108) mmol/day (salt equivalent 6.1 g/day) and 47 (95% CI 45 to 49) mmol/day, respectively. Mean molar Na:K ratio was 2.4 (95% CI 2.3 to 2.5). 72% of children exceeded the age-specific upper level for sodium intake. After adjustment for age, sex and day of urine collection, children from a low socioeconomic background excreted 10.0 (95% CI 17.8 to 2.1) mmol/day more sodium than those of high socioeconomic background (p=0.04). The major sources of sodium were bread (14.8%), mixed cereal-based dishes (9.9%) and processed meat (8.5%). The major sources of potassium were dairy milk (11.5%), potatoes (7.1%) and fruit/vegetable juice (5.4%). Core foods provided 55.3% of dietary sodium and 75.5% of potassium while discretionary foods provided 44.7% and 24.5%, respectively.

CONCLUSIONS

For most children, sodium intake exceeds dietary recommendations and there is some indication that children of lower socioeconomic background have the highest intakes. Children are consuming about two times more sodium than potassium. To improve sodium and potassium intakes in schoolchildren, product reformulation of lower salt core foods combined with strategies that seek to reduce the consumption of discretionary foods are required.

Iodine Intakes of Victorian Schoolchildren Measured Using 24-h Urinary Iodine Excretion

Mandatory fortification of bread with iodized salt was introduced in Australia in 2009, and studies using spot urine collections conducted post fortification indicate that Australian schoolchildren are now replete. However an accurate estimate of daily iodine intake utilizing 24-h urinary iodine excretion (UIE μg/day) has not been reported and compared to the estimated average requirement (EAR). This study aimed to assess daily total iodine intake and status of a sample of primary schoolchildren using 24-h urine samples. Victorian primary school children provided 24-h urine samples between 2011 and 2013, from which urinary iodine concentration (UIC, μg/L) and total iodine excretion (UIE, μg/day) as an estimate of intake was determined. Valid 24-h urine samples were provided by 650 children, mean (SD) age 9.3 (1.8) years (n = 359 boys). The mean UIE of 4–8 and 9–13 year olds was 94 (48) and 111 (57) μg/24-h, respectively, with 29% and 26% having a UIE below the age-specific EAR. The median (IQR) UIC was 124 (83,172) μg/L, with 36% of participants having a UIC < 100 μg/L. This convenience sample of Victorian schoolchildren were found to be iodine replete, based on UIC and estimated iodine intakes derived from 24-h urine collections, confirming the findings of the Australian Health Survey.

The Development of a Web-Based Program to Reduce Dietary Salt Intake in Schoolchildren: Study Protocol

BACKGROUND

Salt intake of schoolchildren in the Australian state of Victoria is high. To protect future cardiovascular health, interventions that seek to reduce the amount of salt in children's diets are required.

OBJECTIVE

We sought to develop and pilot test a Web-based program (Digital Education to Limit Salt Intake in the Home [DELISH]) that aims to reduce dietary salt intake among schoolchildren and to improve child and parent knowledge, attitudes, and behaviors related to salt intake. This paper presents the DELISH study protocol, along with pilot findings used to inform the development of the program.

METHODS

The DELISH program is a 5-week Web-based intervention that targets schoolchildren aged 7-10 years and their parents. This is a single-arm study with a pretest and posttest design. We will assess change in salt intake through analysis of 24-hour urinary sodium excretion. Children and parents will complete online surveys assessing knowledge, attitudes, and behaviors related to salt intake. We will assess feasibility of the program via process measures, which include metrics to describe intervention uptake (eg, number of children who complete Web-based sessions and of parents who view online newsletters) and evaluation surveys and interviews conducted with children, parents, and schoolteachers. The first 2 Web sessions developed for children were pilot tested in 19 children aged 8-12 years.

RESULTS

Findings from pilot testing indicated that most children (session 1: 18/19, 95%; and session 2: 19/19, 100%) enjoyed completing each session and liked the inclusion of comic strips and interactive games. Commonly reported areas of improvement related to sessions being text and content heavy. Based on these findings, we simplified sessions and developed 3 additional sessions for use in the DELISH program. The DELISH program was implemented during June-December 2016. We expect to have results from this study at the end of 2017.

CONCLUSIONS

To our knowledge, this is the first Australian study to examine the effectiveness of a Web-based program to reduce salt intake among children in primary school. If shown to be acceptable and effective in lowering salt intake, the DELISH program could be tested using a more rigorous randomized controlled trial design.

Association between Parent and Child Dietary Sodium and Potassium Intakes as Assessed by 24-h Urinary Excretion

The aim of this study was to assess the association between parent and child sodium (Na) and potassium (K) intake as assessed by 24-h urinary excretion (24hUE). Primary school children and their parent(s) provided one 24-h urine sample and information on cooking and children's discretionary salt use. Valid urine samples were provided by 108 mothers (mean age 41.8 (5.1) (SD) years, Na 120 (45) mmol/day) (7.0 g/day salt equivalent) and 40 fathers (44.4 (4.9) years, Na 152 (49) mmol/day (8.9 g/day salt), and 168 offspring (51.8% male, age 9.1 (2.0) years, Na 101 (47) mmol/day (5.9 g/day salt). When adjusted for parental age, child age and gender a 17 mmol/day Na (1 g/day salt) increase in mother's 24hUE was associated with a 3.4 mmol/day Na (0.2 g/day salt) increase in child's salt 24hUE (p = 0.04) with no association observed between father and child. Sixty-seven percent of parents added salt during cooking and 37% of children added salt at the table. Children who reported adding table salt had higher urinary excretion than those who did not (p = 0.01). The association between mother and child Na intake may relate to the consumption of similar foods and highlights the importance of the home environment in influencing total dietary sodium intake.

24-h urinary sodium excretion is associated with obesity in a cross-sectional sample of Australian schoolchildren

Emerging evidence indicates that dietary Na may be linked to obesity; however it is unclear whether this relationship is independent of energy intake (EI). The aim of this study was to assess the association between Na intake and measures of adiposity, including BMI z score, weight category and waist:height ratio (WHtR), in a sample of Australian schoolchildren. This was a cross-sectional study of schoolchildren aged 4-12 years. Na intake was assessed via one 24-h urine collection. BMI was converted to age- and sex-specific z scores, and WHtR was used to define abdominal obesity. In children aged ≥8 years, EI was determined via one 24-h dietary recall. Of the 666 children with valid urine samples 55 % were male (average age 9·3 (sd 1·8) years). In adjusted models an additional 17 mmol/d of Na was associated with a 0·10 higher BMI z score (95 % CI 0·07, 0·13), a 23 % (OR 1·23; 95 % CI 1·16, 1·31) greater risk of being overweight/obese and a 15 % (OR 1·15; 95 % CI 1·09, 1·23) greater risk of being centrally obese. In the subsample of 8-12-year-old children (n 458), adjustment for EI did not markedly alter the associations between Na and adiposity outcomes. Using a robust measure of daily Na intake we found a positive association between Na intake and obesity risk in Australian schoolchildren, which could not be explained by total energy consumption. To determine whether this is a causal relationship, longitudinal studies, with high-quality measures of Na and EI, are required.