FNCE 2023
Session 357. Providing MNT for the Pediatric Type 1 Diabetes Population: What Does the Evidence Show?
Monday, October 9, 8:30 AM - 9:30 AM

See session information ♦ See EAL review results

NA: Sodium or Sodium Chloride (2010)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

To analyze the effects of varying levels of sodium intake on blood pressure in men and women according to various subgroups, including age and hypertension status, race or ethnicity, and hypertension status in context with gender and race or ethnicity.

Inclusion Criteria:

Men and women with a systolic BP ranging from 120 to 159mm HG and diastolic BP ranging from 80 to 95mm Hg.

Exclusion Criteria:

None disclosed.

Description of Study Protocol:

Design

After completing a two-week run-in period in which the participants ate the control diet at the higher sodium level, the 412 participants were randomly assigned to either the DASH diet or a control diet. Within the assigned diets were three 30-day periods each with different sodium levels presented in random order: higher (150mmol per day), intermediate (100mmol per day) or lower (50mmol per day) in the 2,100kcal version of the diets.

Intervention

Control or DASH diet. 

Statistical Analysis

Because of reduced sample size, especially in subgroups jointly defined by more than one factor, power was limited. Therefore we report P values from 0.05 to 0.10 in addition to P values less than 0.05 to help readers better evaluate the consistency of the results.

 

Data Collection Summary:

Timing of Measurements

  • BP measured at three visits during screening, at two visits during the two-week run-in and on five of the last nine days of each of the three feeding periods
  • A pair of BP measurements was taken on each day and averaged
  • Baseline BP was the average of the five pairs of BP values before beginning the assigned diets
  • The end-of-feeding BP was the average of the five pairs of BP values obtained at the end of each 30-day feeding period
  • Hypertension status was defined as systolic BP of more than or equal to 140mm Hg and diastolic BP of more than or equal to 90 mm Hg. 

Dependent Variables

Blood pressure.

Independent Variables

Sodium intake. 


 

 

Description of Actual Data Sample:
  • Initial N: N=412 (female, 234; men, 178)
  • Attrition (final N): N=412
  • Age: 23 to 76 years of age
  • Ethnicity: African-American and non-African-American
  • Anthropometrics: Baseline BP similar between non-hypertensives, stage one hypertension, African-Americans, non-African-Americans, men, women and less than or 45 years old enrolled in either control or DASH diet
  • Location: US. 
Summary of Results:

 

 

      Systolic BP           Diastolic BP          
      Control     DASH     Control     DASH    
Characteristic Control N DASH N Lower vs. Higher Lower vs. Intermediate Intermediate vs. Higher Lower vs. Higher Lower vs. Intermediate Intermediate vs. Higher Lower vs. Higher Lower vs. Intermediate Intermediate vs. Higher Lower vs. Higher Lower vs. Intermediate Intermediate vs. Higher
Non-hypertensive 121 123 -5.6 -3.4 -2.2 -1.7 -0.6 -1.1 -2.8 -2.0 -0.8 -1.1 -0.3 -0.8
Hypertensive 83 85 -8.3 -6.2 -2.1 -5.0 -3.3 -1.6 -4.4 -2.9 -1.5 -2.5 -2.0 -0.5
Non-African American 89 89 -5.0 -3.0 -2.1 -2.2 -1.3 -0.9 -2.2 -1.6 -0.6 -1.3 -1.0 -0.3
African-American 115 119 -8.0 -5.7 -2.2 -3.6 -2.1 -1.5 -4.5 -3.0 -1.5 -1.9 -1.0 -0.9
Women 111 123 -7.5 -5.8 -1.7 -4.0 -2.4 -1.6 -3.7 -2.8 -0.8 -1.7 -1.2 -0.5
Men 93 85 -5.7 -3.1 -2.6 -1.7 -0.7 -0.9 -3.2 -1.9 -1.4 -1.6 -0.7 -0.8
Less than or  or equal to 45 years 75 97 -5.3 -3.9 -1.4 -1.4 -0.1 -1.3 -2.8 -2.6 -0.2 -1.1 -0.6 -0.5
More than 45 years 129 111 -7.5 -5.0 -2.6 -4.5 -3.2 -1.3 -3.8 -2.3 -1.6 -2.2 -1.3 -0.8
Not obese 122 130 -6.6 -4.6 -2.0 -3.7 -2.2 -1.6 -3.5 -2.3 -1.2 -1.8 -1.3 -0.5
Obese 82 78 -6.9 -4.6 -2.3 -1.8 -1.1 -0.7 -3.5 -2.6 -0.9 -1.3 -0.5 -0.8
                             
                             
                             

Estimated effects of sodium reduction (pairwise contrasts between sodium levels are displayed) on BP by diet arm for subgroups of DASH-sodium participants defined by a single characteristic.

 

 

Author Conclusion:

Within each diet, the lower the sodium level, the greater the mean reduction in BP. The DASH diet resulted in lower mean BP at each sodium level.  The joint effect of the DASH diet and reduced sodium intake augment each other but are less than fully additive. Age had a strong and graded influence on the effect of sodium reduction on BP in those eating the control diet or the DASH diet. It is reasonable to speculate that adherence to the combination of the DASH diet and reduced sodium intake might blunt the well-documented increase in BP that occurs with age.

Funding Source:
Government: National Institutes of Health, NHLBI Bethesda, MD and the General Clinical Research Center Program of the National Center for Research Resources, Bethesda, MD
Reviewer Comments:

This was an analysis of the DASH-sodium trial. Recruitment and exclusion criteria was not given. Information was not given on whether or not participants followed the diet carefully. Other factors such as BP medication was not included.

Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
 
Validity Questions
  1. Was the research question clearly stated? Yes
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
  1.3. Were the target population and setting specified? Yes
  2. Was the selection of study subjects/patients free from bias? ???
2. Was the selection of study subjects/patients free from bias? ???
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? No
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? No
  2.2. Were criteria applied equally to all study groups? N/A
  2.2. Were criteria applied equally to all study groups? N/A
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
  3. Were study groups comparable? Yes
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) ???
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) ???
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) ???
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) ???
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
  4. Was method of handling withdrawals described? N/A
4. Was method of handling withdrawals described? N/A
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) N/A
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? N/A
  4.4. Were reasons for withdrawals similar across groups? N/A
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
  5. Was blinding used to prevent introduction of bias? Yes
5. Was blinding used to prevent introduction of bias? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? Yes
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) Yes
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
  6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? Yes
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? ???
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? ???
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? No
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? No
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? No
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? No
  6.6. Were extra or unplanned treatments described? No
  6.6. Were extra or unplanned treatments described? No
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
  7. Were outcomes clearly defined and the measurements valid and reliable? Yes
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? ???
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? ???
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? ???
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? ???
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? No
  7.6. Were other factors accounted for (measured) that could affect outcomes? No
  7.7. Were the measurements conducted consistently across groups? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
  8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? No
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? No
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? No
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? No
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
  9. Are conclusions supported by results with biases and limitations taken into consideration? No
9. Are conclusions supported by results with biases and limitations taken into consideration? No
  9.1. Is there a discussion of findings? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? No
  9.2. Are biases and study limitations identified and discussed? No
  10. Is bias due to study's funding or sponsorship unlikely? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes
  10.2. Was the study free from apparent conflict of interest? Yes