Education to Decrease in Sodium Intake Evaluated With 24 Hour Urinary Sodium Excretion (RCT)

According to reports from the World Health Organization (WHO) in 2015, the prevalence of hypertension in the world is 1.13 billion people, representing 1 in 4 men and 1 in 5 women (WHO, 2019). In the Americas, every year 1.6 million people die from cardiovascular disease and it has been reported that 20-40% of the adult population suffer hypertension, representing 250 million people affected.

High salt intake (NaCl) is considered an essential risk factor in the development and progression of hypertension.In addition, several studies indicate that sodium in the diet is directly associated with blood pressure.Deleterious effects of high sodium intake associated with endothelial damage have also been reported in normotensive individuals independent of high blood pressure , reduced endothelial function and microvascular reactivity due to oxidative stress.Likewise, a decrease in the nitric oxide of the endothelium has been described that precedes the development of atherosclerotic plaques, which is known through a mechanism where nitric oxide inhibits platelet aggregation, the adhesion of platelets to collagen fibers and other adhesive proteins, as well as the stimulation of adipocyte hypertrophy by increasing the enzymatic activity of leptin and lipogenic enzymes .With type 2 diabetes mellitus (DM2) and increased insulin resistance through hemodynamic changes in the kidneys by sustained sodium reabsorption.In addition, high salt intake has also been associated with kidney disease, osteoporosis, kidney stone formation and stomach cancer.Recently, as a potential modulator of inflammatory and autoimmune diseases through direct and indirect mechanisms of cellular immunity.Therefore, international organizations recommend decreasing sodium intake in the diet. The WHO recommends that sodium intake be 2000 mg/d (equivalent to 5g of salt) and potassium intake 3.5 g/d in adults, to prevent chronic diseases such as hypertension, risk of heart disease and stroke.

Methodology Study design: a randomized controlled, parallel-group, prospective trial was conducted.

Sample: n= 114, undergraduate students from the Autonomous University of Baja California.

For the sample size of the comparison of two repeated averages in two different groups of participants.Public-Public Software was used for its calculationGRANMO developed by the URLEC Consortium of the research groups on Cardiovascular Risk and Nutrition and on Epidemiology and Cardiovascular Genetics of the IMIM-Hospital del Mar Research Program on Inflammatory and Cardiovascular Processes.

Variables Weight: To be measured with a scale brand TANITA Digital Body Fat Scale for Composition Monitor. Model BC-730F FitScan, (Tokyo, Japan), accurate to 0.1 Kg. Participants will be weighed with light clothing and without shoes.

Size: The size shall be measured without shoes and by the use of a SECA 213 (Hamburg, Germany) statistic, accurate to 0.1cm.

Body Mass Index (BMI): To be calculated according to the following formula: BMI= Weight (kg)/Size2 (cm). And it will be classified according to the criteria established by the WHO in: normal weight (18.5 to 25.0 kg/m2), overweight (25 to 30 kg/m2) and obesity ( 30 kg/m2).

Blood Pressure (BP): slope of the equipment (an automatic digital tensiometer validated for example OMRON will be used, according to the protocol for determining the sodium concentration.

Urinary excretion of sodium and potassium of 24h: It will be calculated by the method of selective electrons of ions in the Specialized Clinical Laboratory of Hematology and Transfusion Unit.

Intervention group Low sodium diet: Restriction of foods with high sodium content through educational newsletters once a week for 4 weeks control group Usual diet Age: 18- 30 years Gender: Male will be coded as 1, and female as 2 at the time of being captured in the database.

Weight: stage diagnosis according to body mass index, categories of normopeso, overweight or obesity according to the WHO.

Diagnosis of blood pressure: according to The eighth Joint National Committee guidelines (JNC 8) published in 2014.

Statistical Analysis: a sample size per group was calculated, with a statistical power of 80% to two tails, with a p= 0.05 to detect a difference of 1000 mg of sodium.A descriptive analysis shall be made of each of the variables expressed according to their level of measurement (averages or medians) with their respective dispersion measurement.

body mass index will be analyzed by category and sex for categorical data with the square Pearson's chi-squared test.

Correlation and simple linear regression shall be applied for body mass index, blood pressure and 24 hour sodium urinary excretion prior to the intervention.

The Student t test will be applied for related samples. Assumptions will be sought for parametric statistical analysis and the corresponding statistical test will be applied if the assumptions are met.The student t-test shall be applied for independent samples and mean differences in the intervention vs control group shall be analysed for 24-hour urinary sodium excretion data.The Kolmogorov-Smirnov test will be applied to see if there is a normal distribution.The Levene statistic shall be applied to assess homoscedasticityThe ANOVA test of a factor to analyze mean difference in the intervention group vs control group, in urinary sodium excretion by sex, will be applied.FACTORIAL ANOVA shall be applied to analyse mean difference in the intervention group vs control group in urinary sodium excretion (the same for potassium excretion) with the BMI categories, sex, for the categories of a low sodium diet (less 2000 mg of Na) and the categories of a standard sodium diet( greater than 3500 mg Na).

Procedure:

The study was submitted for authorization to the graduate committee of the Doctorate in Nutrition and Behavioral Sciences and to the ethics committee of the University Autonomous of Baja California.

Explanation of study purpose to participants and signature of informed consent. Details of how to collect the sample shall be given and the day and time of delivery indicated. A plastic canister with 24h urine collection capacity will be provided.

Blood pressure determination: Participants will be advised not to exercise, eat, drink, or smoke 30 minutes before taking their blood pressure. Before measuring the blood pressure, the participant will be asked to sit in a comfortable and quiet place for at least five minutes, with his back supported and without crossing his legs. When asking questions about behavior and personal medical history, just before taking the measurements, the participant should rest at least five minutes before starting the blood pressure test.

WHO recommends taking three blood pressure measurements. During data analysis, the average of the second and third readings is calculated. The participant must rest for one minute between each reading .

Heart rate measurement and recording should be done three times, along with blood pressure measurement and recording. The automatic tensiometer simultaneously presents the results.

The average of three measurements shall be calculated before the intervention and during the follow-up period.

24-hour urine collection: The urine sample will be collected in Plastic container: with capacity of three liters wide mouth BD Vacutainer, the second urine of the day until the first of the next morning. The sample shall be delivered on the agreed day for analysis.

The sodium in 24-hour urine excretion shall be estimated by selective ion electrode technology: the total sample shall be mixed, 200 μl shall be separated from the collected urine and diluted in 200 μl ml of urine diluent Urine thinner: (PN AV-BP0344D) company name and country of origin (if USA include state): Diluent used to analyze the urine sample in the electrolyte analyzer, (1:1 dilution). Select " urine mode" to analyze the sample. At the end, the results of the electrolytes Na, K and Cl will be reported on the screen. The result of the first measurement will be taken.They will be compared with the reference values, considering age and sex.

KontrolLab: Electrolyte Analyzer, KontroLab Analyzer is an in vitro diagnostic equipment manufactured with state-of-the-art technology, accurate, accurate and designed to be easy to use and maintain.

It is based on the properties of its transducers or sensors (electrodes) to be selective to a specific Ion in solution.

This is achieved thanks to the fact that the membranes of the Ion selective Electrodes develop a potential (with respect to a Reference electrode) proportional to the activity of the Ion in solution for which they are selective.

ISE Pack reagents: (PV AV-BP5186D) Include place of origin and company name: The package contains the following reagents for the calibration of sodium, potassium, chlorine, ionised calcium and lithium from the electrolyte analyser.

To obtain the value in mmol / 24 hours, it must be multiplied by the 24-hour sample volume of the patient, expressed in liters.

To blood pressure:

An automatic digital tensiometer validated according to the protocol for determining the sodium concentration, PAHO-WHO, 2010. It will be used marca OMRON: Model: HEM-7121.Distribuited by OMRON HEALTHCARE,INC.Illinois,U.S.A.

Intervention: They will be given recommendations for a low-sodium diet: Restriction of foods with high sodium content.

The duration time will be four weeks for assessment of BP and sodium excretion and consumption of foods high in salt; and at 24 weeks for the assessment of BP and consumption of foods high in salt.

Estimation of the consumption of fruits and vegetables,salt added to meals before and after meals and the consumption of industrialized products, at four and twenty-four weeks.

Physical activity and / or exercise will be assessed (type of exercise: aerobic or anaerobic and constancy: time 15 min, 30 min, 60 min, 120 min.

Questionnaire: identification of consumption fruits and vegetables, industrialized products, frequency, duration and type of exercise.