Dialysate Composition for Hemodialysis: Changes and Changing Risk

Dialysate composition is a critical aspect of the hemodialysis prescription. Despite this, trial data are almost entirely lacking to help guide the optimal dialysate composition. Often, the concentrations of key components are chosen intuitively, and dialysate composition may be determined by default based on dialysate manufacturer specifications or hemodialysis facility practices. In this review, we examine the current epidemiological evidence guiding selection of dialysate bicarbonate, calcium, magnesium, and potassium, and identify unresolved issues for which pragmatic clinical trials are needed.

The Safety and Tolerability of 5-Aminolevulinic Acid Phosphate with Sodium Ferrous Citrate in Patients with Type 2 Diabetes Mellitus in Bahrain

Type 2 diabetes mellitus is prevalent especially in Gulf countries and poses serious long-term risks to patients. A multifaceted treatment approach can include nutritional supplements with antioxidant properties such as 5-aminolevulinic acid (5-ALA) with sodium ferrous citrate (SFC). This prospective, randomized, single-blind, placebo-controlled, dose escalating pilot clinical trial assessed the safety of 5-ALA with SFC at doses up to 200 mg 5-ALA/229.42 mg SFC per day in patients living in Bahrain with type 2 diabetes mellitus that was uncontrolled despite the use of one or more antidiabetic drugs. Fifty-three patients (n = 53) from 3 sites at one center were enrolled by Dr. Feryal (Site #01), Dr. Hesham (Site #02), and Dr. Waleed (Site #03) (n = 35, 5-ALA-SFC; n = 18, placebo). There was no significant difference in incidence of adverse events reported, and the most frequent events reported were gastrointestinal in nature, consistent with the known safety profile of 5-ALA in patients with diabetes. No significant changes in laboratory values and no difference in hypoglycemia between patients receiving 5-ALA and placebo were noted. Overall, the current results support that use of 5-ALA-SFC up to 200 mg per day taken as 2 divided doses is safe in patients taking concomitant oral antidiabetic medications and may offer benefits in the diabetic population. This trial is registered with ClinicalTrials.gov NCT02481141.

[Potassium and blood pressure, an old story, revisited]

Food in industrialized countries is rich in processed products with a high sodium and low potassium content. There is abundant evidence in the literature depicting the relationship between a high daily sodium/potassium intake ratio and the high prevalence of arterial hypertension in modern societies. There is also increasing evidence suggesting a blood pressure lowering effect of potassium, especially in cases of high sodium intake or in patients with increased salt sensibility. Our dietary advice for the prevention and treatment of hypertension should follow a thorough evaluation of our patients' daily nutritional habits and should not only focus on sodium intake but also aim for a balanced sodium/potassium uptake.

Assessment of mineral intake in the diets of Polish postmenopausal women in relation to their BMI-the RAC-OST-POL study : Mineral intake in relation to BMI

BACKGROUND

The diets of postmenopausal women in Western countries tend to be deficient in minerals, even if the energy value is at the recommended level. The objective of the presented population-based cohort study was to assess the intake of minerals (sodium, potassium, calcium, phosphorus, magnesium, iron, zinc and copper) in the diets of women aged above 55 years and to analyse the relations between BMI and mineral intake in this group.

METHODS

The study was conducted in a group of 406 women who were randomly recruited from the general population of those aged above 55 years. The main outcome measures included BMI, reported sodium, potassium, calcium, phosphorus, magnesium, iron, zinc and copper intake assessed by dietary record (conducted during two typical, non-consecutive days). The distribution was verified with the use of the Shapiro-Wilk test. The comparison between groups was conducted using ANOVA with the LSD post hoc test or Kruskal-Wallis ANOVA with multiple comparisons. A comparison of satisfying nutritional needs was conducted using the chi-square test.

RESULTS

Normal body weight individuals were characterised by lower sodium intake per 1000 kcal of diet than obese class II and III individuals (BMI ≥ 35.0 kg/m(2)). Overweight individuals were characterised by lower potassium and magnesium intake per 1000 kcal of diet than obese class I individuals (BMIϵ < 30.0; 35.0 kg/m(2)). The majority of individuals was characterised by insufficient potassium, calcium and magnesium intake. No differences in satisfying nutritional needs between BMI groups were observed for all minerals.

CONCLUSIONS

Following an improperly balanced diet was observed in the group of postmenopausal female individuals analysed. It was stated that the daily intake of all the assessed minerals was not BMI-dependent for the postmenopausal female individuals, but the nutrient density of diet (for sodium, potassium and magnesium) was associated with BMI.

Feasibility of collecting 24-h urine to monitor sodium intake in the National Health and Nutrition Examination Survey

BACKGROUND

Twenty-four-hour urine sodium excretion is recommended for monitoring population sodium intake. Because of concerns about participation and completion, sodium excretion has not been collected previously in US nationally representative surveys.

OBJECTIVE

We assessed the feasibility of implementing 24-h urine collections as part of a nationally representative survey.

DESIGN

We selected a random half sample of nonpregnant US adults aged 20-69 y in 3 geographic locations of the 2013 NHANES. Participants received explicit instructions, started and ended the urine collection in a urine study mobile examination center, and answered questions about their collection. Among those with a complete 24-h urine collection, a random one-half were asked to collect a second 24-h urine sample. Sodium, potassium, chloride, and creatinine excretion were analyzed.

RESULTS

The final NHANES examination response rate for adults aged 20-69 y in these 3 study locations was 71%. Of those examined (n = 476), 282 (59%) were randomly selected to participate in the 24-h urine collection. Of these, 212 persons [75% of those selected for 24-h urine collection; 53% (equal to 71% × 75% of those selected for the NHANES)] collected a complete initial 24-h specimen and 92 persons (85% of 108 selected) collected a second complete 24-h urine sample. More men than women completed an initial collection (P = 0.04); otherwise, completion did not vary by sociodemographic characteristics, body mass index, education, or employment status for either collection. Mean 24-h urine volume and sodium excretion were 1964 ± 1228 mL and 3657 ± 2003 mg, respectively, for the first 24-h urine sample, and 2048 ± 1288 mL and 3773 ± 1891 mg, respectively, for the second collection.

CONCLUSION

Given the 53% final component response rate and 75% completion rate, 24-h urine collections were deemed feasible and implemented in the NHANES 2014 on a subsample of adults aged 20-69 y to assess population sodium intake. This study was registered at clinicaltrials.gov as NCT02723682.

Hypernatremic Dehydration in Young Children: Is There a Solution?

BACKGROUND

Hypernatremic dehydration is a common and potentially life-threatening condition in children. There is currently no consensus as to the optimal strategy for fluid management.

OBJECTIVES

To describe the relationship between the type, route and rate of fluids administered and the rate of decline in serum sodium (Na+) concentration.

METHODS

We reviewed the medical records of all children under the age of 2 years who were hospitalized with hypernatremic dehydration (serum Na+ ≥ 155 mEq/L) in Shaare Zedek Medical Center during the period 2001-2010. Collected data of 62 subjects included initial and subsequent serum Na+ levels, and rate and Na+ concentration of all intravenous and oral fluids administered until the serum Na+ reached ≤ 150 mEq/L.

RESULTS

Median initial serum Na+ was 159.5 mEq/L (IQR 157-163, maximal value 170). The median rate of decline in serum Na+ until serum Na+ reached 150 mEq/L was 0.65 mEq/L/hr (IQR 0.45-0.95). Forty-two children received hypotonic oral fluids which accounted for approximately one-quarter of all fluids they received. There was no significant difference in the rate of decline in serum Na+ between those who consumed oral fluids and those who did not. Neither was there a correlation between the rate of IV fluids, receipt of oral fluids or the degree of dehydration, with the rate of decline in serum Na+. No child experienced an apparent short-term adverse outcome.

CONCLUSIONS

A cumulative rate of 5.9 mI/kg/hr of IV fluid administration may reduce the serum Na+ by an acceptable rate (0.65 mEq/L/hr). Fluid therapy comprising up to 25% hypotonic oral fluids and 75% IV fluids high in Na+ concentration was not associated with any short-term adverse outcome in our patient population.

Sodium Infusion Test for Diagnosis of Primary Aldosteronism in Chinese Population

CONTEXT

The plasma aldosterone concentration (PAC) is less than 5 ng/dL after saline infusion test (SIT) in essential hypertension (EH) and healthy people. It is unclear if the same standard is applicable for Chinese subjects.

OBJECTIVE AND DESIGN

We assessed the serum aldosterone response after SIT in subjects with primary aldosteronism (PA), EH, and healthy volunteers (normal control, NC), and to investigate the optimal aldosterone level of post-SIT for the diagnosis of PA.

SUBJECTS AND SETTING

The study included 120 hypertensive patients who conform to the PA screening criteria and 21 healthy volunteers.

INTERVENTION

All subjects underwent SIT.

MAIN OUTCOME MEASURES

PAC was measured in all subjects before and after SIT. The total sodium intake was estimated from 2 timed 24-hour urinary excretion.

RESULTS

The area under the receiver-operator characteristic curves was higher than under the diagonal (0.967, 95% confidence interval [CI]: 0.94-0.993). The best cutoff value for PAC after SIT for diagnosis of PA was 11.45 ng/dL, with sensitivity and specificity of 88.2% and 95.4%, respectively. The PAC of post-SIT was more than 10 ng/dL in most PA patients, whereas it was greater than 5 ng/dL in both EH and NC except for 1 at 4.93 ng/dL. Serum aldosterone level was unrelated to dietary salt intake.

CONCLUSIONS

The optimal post-SIT aldosterone cutoff value for identifying PA was 11.45 ng/dL in Chinese patients. However, the PAC higher than 5 ng/dL after SIT was found in a majority of EH and healthy subjects. The cutoff value of aldosterone post-SIT is higher than the current clinical recommendations and practice guidelines of The Endocrine Society. We found no relationship between high salt intake and lower responses of renin aldosterone system to high loading with saline infusion.

Aldosterone increases oxygen consumption of rectal epithelia of normal, sodium-deprived and sodiumloaded rats

INTRODUCTION

The colonic epithelium is a classical aldosterone target, but the effect of the hormone on the oxygen consumption rate (QO2 ) of this tissue is unknown. Objectives. We aimed at assessing, in the rectal epithelium of rats fed with diets of different sodium content, the effect of epithelial sodium channel (ENaC) blockade on short-circuit current (ISC ) and QO2 , and the acute effect of aldosterone incubation on ISC and QO2 .

METHODS

Adult male rats were fed with normal, low or high-sodium diets for 8 days. Plasma sodium and serum aldosterone were measured. Isolated mucosa preparations from the rectal portion of the colon were mounted in Ussing chambers modified to measure ISC and QO2.

RESULTS

Baseline ISC and QO2 were highest in sodium-deprived rats. Both were proportionally reduced by amiloride (0.1 mM) in this group and in the normal sodium group, but not in sodium-loaded rats. In separate experiments, incubation with aldosterone (10 nM) for 7 h increased ISC and QO2 in all groups; increases were larger in the normal and sodium-loaded groups. Amiloride decreased both ISC and QO2 , abolishing the differences between groups. Linear regression of the decrease in QO2 and ISC after amiloride showed the steepest slope for the sodium-deprived group and the flattest one for the sodium-loaded group.

CONCLUSIONS

Baseline epithelial QO2 of sodium-deprived and control rats is reduced by ENaC blockade. Aldosterone increased QO2 proportionally to ISC augmentation in all groups, but the coupling between aerobic metabolism and electrogenic transport seems more efficient in sodium-deprived animals.

Enema ion compositions for enhancing colorectal drug delivery

Delivering drugs to the colorectum by enema has advantages for treating or preventing both local and systemic diseases. However, the properties of the enema itself are not typically exploited for improving drug delivery. Sodium ions are actively pumped out of the lumen of the colon, which is followed by osmotically-driven water absorption, so we hypothesized that this natural mechanism could be exploited to drive nanoparticles and drugs to the colorectal tissue surface. Here, we report that sodium-based, absorption-inducing (hypotonic) enemas rapidly transport hydrophilic drugs and non-mucoadhesive, mucus penetrating nanoparticles (MPP), deep into the colorectal folds to reach virtually the entire colorectal epithelial surface. In contrast, isotonic and secretion-inducing (hypertonic) vehicles led to non-uniform, poor surface coverage. Sodium-based enemas induced rapid fluid absorption even when moderately hyper-osmolal (~350 mOsm) compared to blood (~300 mOsm), which suggests that active sodium absorption plays a key role in osmosis-driven fluid uptake. We then used tenofovir, an antiretroviral drug in clinical trials for preventing HIV, to test the effects of enema composition on local and systemic drug delivery. We found that strongly hypotonic and hypertonic enemas caused rapid systemic drug uptake, whereas moderately hypotonic enemas with ion compositions similar to feces resulted in high local tissue levels with minimal systemic drug exposure. Similarly, moderately hypotonic enemas provided improved local drug retention in colorectal tissue, whereas hypertonic and isotonic enemas provided markedly reduced drug retention in colorectal tissue. Lastly, we found that moderately hypotonic enema formulations caused little to no detectable epithelial damage, while hypertonic solutions caused significant damage, including epithelial sloughing; the epithelial damage caused increased systemic drug absorption and penetration of MPP into colorectal tissue, a potential advantage in certain drug delivery applications. In summary, we illustrate that enema composition can be adjusted to maximize local versus systemic drug delivery, and that mildly hypotonic, sodium-based vehicles can provide uniform drug and MPP delivery in the colon that maximizes local drug concentrations.

Aggregate blood pressure responses to serial dietary sodium and potassium intervention: defining responses using independent component analysis

BACKGROUND

Hypertension is a complex trait that often co-occurs with other conditions such as obesity and is affected by genetic and environmental factors. Aggregate indices such as principal components among these variables and their responses to environmental interventions may represent novel information that is potentially useful for genetic studies.

RESULTS

In this study of families participating in the Genetic Epidemiology Network of Salt Sensitivity (GenSalt) Study, blood pressure (BP) responses to dietary sodium interventions are explored. Independent component analysis (ICA) was applied to 20 variables indexing obesity and BP measured at baseline and during low sodium, high sodium and high sodium plus potassium dietary intervention periods. A "heat map" protocol that classifies subjects based on risk for hypertension is used to interpret the extracted components. ICA and heat map suggest four components best describe the data: (1) systolic hypertension, (2) general hypertension, (3) response to sodium intervention and (4) obesity. The largest heritabilities are for the systolic (64%) and general hypertension (56%) components. There is a pattern of higher heritability for the component response to intervention (40-42%) as compared to those for the traditional intervention responses computed as delta scores (24%-40%).

CONCLUSIONS

In summary, the present study provides intermediate phenotypes that are heritable. Using these derived components may prove useful in gene discovery applications.

Role of sodium and water in hypertensive patients on maintenance hemodialysis

In 46 patients of the chronic hemodialysis program blood pressure regulation was studied according to variations of sodium and fluid balance. A strong relationship was observed between blood pressure and the amount of exchangeable sodium. In the hypertensive patients exchangeable sodium was increased depite fulfilled clinical signs of sufficient dehydration. The blood volume was found to be small and the plasma renin activity increased in those hypertensive patients, in which sufficient fluid depletion was inhibited by extreme fluctuations of the blood pressure during dialysis. A diminution of the sodium concentration keeping the fluid balance constant induced an increase of blood pressure and deteriorated the subjective feeling of the patients. By an increase of the sodium concentration up to 155 mEq/l severe blood pressure fluctuations during during dialysis could be prevented, although further fluid was taken off by ultrafiltration. This effect seemed to be mediated--at least partly--by an increase of the low blood volume and a suppression of plasma renin activity. After the patients became normotensive, dialysis procedure could be continued with normal sodium concentration. By a temporary high sodium regimen of the dialysis procedure some patients with renal failure and 'uncontrollable hypertension' can be preserved from bilateral nephrectomy.

Dietary mineral intakes of rural midlife to older adult women with prehypertension in Midwestern United States

OBJECTIVES

Midlife to older rural women with prehypertension are at increased risk for hypertension and its impact on cardiovascular health with advancing age. Because modification of dietary factors could help alleviate risk, the objective of this study was to explore calcium, magnesium, potassium and sodium intakes of midlife to older rural women, with identification of their top food sources.

DESIGN

Survey of baseline dietary intake data of women and comparison to standard recommendations.

SETTING

Rural Midwestern United States.

PARTICIPANTS

289 rural women, age 40-69, with prehypertension who volunteered for lifestyle modification to reduce blood pressure.

MEASUREMENTS

Baseline nutrition data using the Block Health Habit and History Questionnaire were collected over a twelve-month rolling enrollment period from rural women with prehypertension. Mineral intakes were calculated and compared to recommended standards. Top ten foods contributing to each mineral were identified.

RESULTS

The percent of women who met the Recommended Dietary Allowance (RDA)/Adequate Intake (AI) recommendations for their age groups ranged from a high 42.9% for magnesium to a low of 4.2% for potassium. Mean intakes of calcium, magnesium and potassium were all below recommended levels and sodium intakes were above recommendation.

CONCLUSION

Midlife to older rural US women with prehypertension were eating some of the foods that would help them meet mineral recommendations. As a preventive approach to reducing hypertension risk, clinical practice could include advising on ways to increase both commonly and less commonly consumed nutrient-rich foods with awareness of what is typically available in the rural area.

Effects of dietary sodium and the DASH diet on the occurrence of headaches: results from randomised multicentre DASH-Sodium clinical trial

OBJECTIVES

Headaches are a common medical problem, yet few studies, particularly trials, have evaluated therapies that might prevent or control headaches. We, thus, investigated the effects on the occurrence of headaches of three levels of dietary sodium intake and two diet patterns (the Dietary Approaches to Stop Hypertension (DASH) diet (rich in fruits, vegetables and low-fat dairy products with reduced saturated and total fat) and a control diet (typical of Western consumption patterns)).

DESIGN

Randomised multicentre clinical trial.

SETTING

Post hoc analyses of the DASH-Sodium trial in the USA.

PARTICIPANTS

In a multicentre feeding study with three 30 day periods, 390 participants were randomised to the DASH or control diet. On their assigned diet, participants ate food with high sodium during one period, intermediate sodium during another period and low sodium during another period, in random order.

OUTCOME MEASURES

Occurrence and severity of headache were ascertained from self-administered questionnaires, completed at the end of each feeding period.

RESULTS

The occurrence of headaches was similar in DASH versus control, at high (OR (95% CI)=0.65 (0.37 to 1.12); p=0.12), intermediate (0.57 (0.29 to 1.12); p=0.10) and low (0.64 (0.36 to 1.13); p=0.12) sodium levels. By contrast, there was a lower risk of headache on the low, compared with high, sodium level, both on the control (0.69 (0.49 to 0.99); p=0.05) and DASH (0.69 (0.49 to 0.98); p=0.04) diets.

CONCLUSIONS

A reduced sodium intake was associated with a significantly lower risk of headache, while dietary patterns had no effect on the risk of headaches in adults. Reduced dietary sodium intake offers a novel approach to prevent headaches.

TRIAL REGISTRATION NUMBER

NCT00000608.

To legislate or not to legislate? A comparison of the UK and South African approaches to the development and implementation of salt reduction programs

The World Health Organization promotes salt reduction as a best-buy strategy to reduce chronic diseases, and Member States have agreed to a 30% reduction target in mean population salt intake by 2025. Whilst the UK has made the most progress on salt reduction, South Africa was the first country to pass legislation for salt levels in a range of processed foods. This paper compares the process of developing salt reduction strategies in both countries and highlights lessons for other countries. Like the UK, the benefits of salt reduction were being debated in South Africa long before it became a policy priority. Whilst salt reduction was gaining a higher profile internationally, undoubtedly, local research to produce context-specific, domestic costs and outcome indicators for South Africa was crucial in influencing the decision to legislate. In the UK, strong government leadership and extensive advocacy activities initiated in the early 2000s have helped drive the voluntary uptake of salt targets by the food industry. It is too early to say which strategy will be most effective regarding reductions in population-level blood pressure. Robust monitoring and transparent mechanisms for holding the industry accountable will be key to continued progress in each of the countries.

Inadequacy of vitamins and minerals among high-school pupils in Ouarzazate, Morocco

OBJECTIVE

To assess micronutrient intakes and the prevalence of inadequacy in a sample of high-school pupils in Ouarzazate, Morocco.

DESIGN

Food records were compiled over three non-consecutive days by pre-trained pupils. Micronutrient intakes were estimated using the DIAL software, adapted to include foods commonly eaten in Morocco. The prevalence of inadequacy was estimated by the proportion of individuals with intakes below the Estimated Average Requirement (EAR) for vitamins B12, A and K, thiamin, riboflavin, niacin, pyridoxine, folate, ascorbic acid, iodine, Ca, Mg and P; below the Adequate Intake (AI) level for pantothenic acid, biotin, Na and K; and using the probability approach for Fe. Data were adjusted for intra-individual variation with exclusion of under-reporters.

SETTING

Ouarzazate, a semi-urban region situated on the southern slopes of the High Atlas with little industrial development but an important tourism sector.

SUBJECTS

A self-selected sample of 312 pupils aged 15-19 years from the five public high schools. After exclusion of under-reporters, 293 remained for analysis.

RESULTS

The highest proportions of below-EAR/AI intakes were seen for pantothenic acid (girls 85·1 %, boys 78·0 %), biotin (boys 83·1 %, girls 79·4 %), thiamin (boys 66·9 %), folate (girls 93·1 %, boys 74·6 %), iodine (boys 94·9 %, girls 88·0 %) and Ca (girls 83·4 %, boys 74·6 %). Na intake was generally in excess whereas K intake was below the AI level. In general, girls had better-quality diets than boys, who appeared to consume more 'empty calories'.

CONCLUSIONS

Our findings suggest that in this population of Moroccan adolescents, nutritional intervention and educational strategies are needed to promote healthy eating habits and correct micronutrient inadequacies. To provide reliable and precise estimates of nutrient intakes, an update of Moroccan food composition databases is urgently needed. We recommend that national authorities address these issues.

Monitoring salt and iodine intakes in Dutch adults between 2006 and 2010 using 24 h urinary sodium and iodine excretions

OBJECTIVE

To monitor the effectiveness of salt-reduction initiatives in processed foods and changes in Dutch iodine policy on Na and iodine intakes in Dutch adults between 2006 and 2010.

DESIGN

Two cross-sectional studies among adults, conducted in 2006 and 2010, using identical protocols. Participants collected single 24 h urine samples and completed two short questionnaires on food consumption and urine collection procedures. Daily intakes of salt, iodine, K and Na:K were estimated, based on the analysis of Na, K and iodine excreted in urine.

SETTING

Doetinchem, the Netherlands.

SUBJECTS

Men and women aged 19 to 70 years were recruited through random sampling of the Doetinchem population and among participants of the Doetinchem Cohort Study (2006: n 317, mean age 48·9 years, 43 % men; 2010: n 342, mean age 46·2 years, 45 % men).

RESULTS

While median iodine intake was lower in 2010 (179 μg/d) compared with 2006 (257 μg/d; P < 0·0001), no difference in median salt intake was observed (8·7 g/d in 2006 v. 8·5 g/d in 2010, P = 0·70). In 2006, median K intake was 2·6 g/d v. 2·8 g/d in 2010 (P < 0·01). In this 4-year period, median Na:K improved from 2·4 in 2006 to 2·2 in 2010 (P < 0·001).

CONCLUSIONS

Despite initiatives to lower salt in processed foods, dietary salt intake in this population remains well above the recommended intake of 6 g/d. Iodine intake is still adequate, although a decline was observed between 2006 and 2010. This reduction is probably due to changes in iodine policy.

A repeated cross-sectional study of socio-economic inequities in dietary sodium consumption among Canadian adults: implications for national sodium reduction strategies

INTRODUCTION

In many countries including Canada, excess consumption of dietary sodium is common, and this has adverse implications for population health. Socio-economic inequities in sodium consumption seem likely, but research is limited. Knowledge of socio-economic inequities in sodium consumption is important for informing population-level sodium reduction strategies, to ensure that they are both impactful and equitable.

METHODS

We examined the association between socio-economic indicators (income and education) and sodium, using two outcome variables: 1) sodium consumption in mg/day, and 2) reported use of table salt, in two national surveys: the 1970/72 Nutrition Canada Survey and the 2004 Canadian Community Health Survey, Cycle 2.2. This permitted us to explore whether there were any changes in socio-economic patterning in dietary sodium during a time period characterized by modest, information-based national sodium reduction efforts, as well as to provide baseline information against which to examine the impact (equitable or not) of future sodium reduction strategies in Canada.

RESULTS

There was no evidence of a socio-economic inequity in sodium consumption (mg/day) in 2004. In fact findings pointed to a positive association in women, whereby women of higher education consumed more sodium than women of lower education in 2004. For men, income was positively associated with reported use of table salt in 1970/72, but negatively associated in 2004.

CONCLUSIONS

An emerging inequity in reported use of table salt among men could reflect the modest, information-based sodium reduction efforts that were implemented during the time frame considered. However, for sodium consumption in mg/day, we found no evidence of a contemporary inequity, and in fact observed the opposite effect among women. Our findings could reflect data limitations, or they could signal that sodium differs from some other nutrients in terms of its socio-economic patterning, perhaps reflecting very high prevalence of excess consumption. It is possible that socio-economic inequities in sodium consumption will emerge as excess consumption declines, consistent with fundamental cause theory. It is important that national sodium reduction strategies are both impactful and equitable.

The relationship between central hemodynamics, morning blood pressure surge, glycemic control and sodium intake in patients with type 2 diabetes and essential hypertension

AIMS

The current study aimed to investigate the relationship between morning blood pressure surge (MBPS), hemodynamic parameters, glycemic control and 24-h urinary sodium excretion (USE) in patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

MBPS and central hemodynamic parameters were assessed from ambulatory blood pressure measurements. In addition to routine biochemistry, 24h urine collection was performed to measure protein, albumin and sodium excretion.

RESULTS

There were 146 (38%) patients with T2DM and 238 (72%) patients without T2DM (control group). Patients with T2DM had statistically higher MBPS compared with patients without T2DM (P<0.0001). In patients with T2DM, MBPS was correlated with HbA1c (rho=0.311, P<0.0001), 24h urinary sodium excretion (USE) (rho=0.292, P=0.004) and various hemodynamic parameters. Additionally, regression analysis showed that being male (P=0.006), the presence of coronary artery disease (P=0.023), HbA1c (P=0.012), and 24h USE (P=0.001) were independently related with log MBPS in T2DM patients.

CONCLUSION

This study demonstrated that T2DM was an independent risk factor for increased MBPS and MBPS was associated with central hemodynamic parameters. Additionally poor glycemic control and sodium intake were associated with worse MBPS in T2DM.

Experimental study of the effects of sodium ion concentrations on the function of the myocardium exposed to cardioplegic ischemia

A new cardioplegic solution based on three natural dipeptides was developed and introduced at the Laboratory of Cardioplegia, A. N. Bakulev Research Center of Cardiovascular Surgery. The electrolyte composition of the solution corresponded to the category of intracellular cardioplegic solutions. The results of 60 experiments on isolated rat hearts were analyzed for choosing the optimal concentration of sodium ions (35, 60, or 80 mmol/liter). The composition of the studied cardioplegic solutions was selected by ion concentrations in the intra- and extracellular fluid. Earlier and most effective recovery of cardiac function with minimum rhythm and conductivity disorders was observed in the group treated with cardioplegic solution with sodium ion concentration of 60 mmol/liter.

Sodium and nutrition labelling: a qualitative study exploring New Zealand consumers' food purchasing behaviours

OBJECTIVE

Dietary sodium reduction is an important public health intervention that would reduce blood pressure and chronic disease. An understanding of how New Zealand consumers' food purchasing behaviour is influenced by perceptions of dietary sodium will inform future sodium-reduction strategies.

DESIGN

The present qualitative study used in-depth interviews of adult consumers to explore consumer knowledge, understanding of food labels and food purchasing behaviour with respect to dietary sodium.

SETTING

New Zealand.

SUBJECTS

A convenience sample of sixteen adult grocery shoppers.

RESULTS

A thematic analysis of the transcripts showed New Zealand consumers lacked the background knowledge necessary to understand and regulate their own salt intake and were unable to interpret existing food labels with respect to dietary salt.

CONCLUSIONS

The findings add further weight to calls for food labels that do not require background knowledge or numerical skills and highlight the need for population-based public health interventions. Education of New Zealand consumers on the health benefits of sodium reduction and how this may be achieved would complement this approach.

Effect of maternal excessive sodium intake on postnatal brain development in rat offspring

OBJECTIVES

Postnatal brain development is affected by the in utero environment. Modern people usually have a high sodium intake. The aim of this study was to investigate the effect of sodium hyperingestion during pregnancy on the postnatal brain development of rat offspring.

METHODS

The sodium-overloaded rats received 1.8% NaCl in their drinking water for 7 days during the last week of gestation. Their body weight, urine, and blood levels of sodium and other parameters were measured. Some rats were sacrificed at pregnancy day 22 and the weight and length of the placenta and foetus were measured. The cerebral cortex and hippocampus were obtained from their offspring at postnatal day 1 and at postnatal weeks 1, 2, 4, and 8. Western blot analyses were conducted with brain tissue lysates.

RESULTS

The sodium-overloaded animals had decreased weight gain in the last week of gestation as well as decreased food intake, increased water intake, urine volume, urine sodium, and serum sodium. There were no differences in placental weight and length. The foetuses of sodium-overloaded rats showed decreased body weight and size, and this difference was maintained postnatally for 2 weeks. In the cerebral cortex and hippocampus of the offspring, the protein levels of myelin basic protein, calmodulin/calcium-dependent protein kinase II, and brain-derived neurotrophic factor were decreased or aberrantly expressed.

DISCUSSION

The present data suggest that increased sodium intake during pregnancy affects the brain development of the offspring.

Sodium administration in critically ill patients in Australia and New Zealand: a multicentre point prevalence study

BACKGROUND

Inadvertent sodium administration in excess of recommended daily requirements has been reported during routine care of critically ill patients.

AIM

To determine the amount and sources of sodium administered in Australian and New Zealand intensive care units.

DESIGN, SETTING AND PARTICIPANTS

Prospective, observational, single-day, point prevalence survey conducted in 46 Australian and New Zealand ICUs on 21 September 2011. All patients present in ICU at 10 am and not receiving an oral diet on the study day were evaluated. Demographic data, ICU admission diagnosis, Acute Physiology and Chronic Health Evaluation (APACHE) II score and sources of sodium administration over the study day were recorded.

RESULTS

356 patients (64% male) were enrolled. Mean (SD) age and weight were 58.5 years (18.0 years) and 81.6 kg (24.0 kg), respectively. Mean ICU admission APACHE II score was 20 (SD, 8). Overall median (interquartile range [IQR]) sodium administration was 224.5 mmol (IQR, 144.9-367.6 mmol), or 2.8 mmol/kg (IQR, 1.6-4.7 mmol/kg). Among patients who were on Day 2-10 of their ICU admission on the study day, sodium sources and amounts administered were: i) maintenance or replacement intravenous (IV) infusions, 69.3mmol; 30.9% of all sodium sources; ii) IV fluid boluses, 36.5 mmol; 16.3%; iii) IV drug boluses, 27.6 mmol; 12.3%; iv) enteral nutrition, 26.5 mmol; 11.8%; v) IV drug infusions, 19.3 mmol; 8.6%; vi) IV flushes, 16.6mmol; 7.4%; vii) blood products, 13.5 mmol; 6%; viii) IV antimicrobials, 11.2mmol; 5%; and ix) parenteral nutrition, 4.3 mmol; 1.9%. Factors associated with sodium administration were site (P = 0.04), age (P < 0.001), administered fluid (P = 0.03) and day of ICU stay (P = 0.01) (multiple linear regression).

CONCLUSION

This point prevalence study suggests that sodium administration in excess of recommended daily requirements may be common in Australia and New Zealand ICUs. The main sodium source was IV maintenance fluids, followed by fluid boluses and drug boluses.