HTN: Sodium (2015)

Citation:

Lancaster KJ, Smiciklas-Wright H, Weltzel LB, Mitchell DC, Friedman JM, Jensen GL. Hypertension-related dietary patterns of rural older adults. Preventive Medicine, 2004; 38: 812-818.

PubMed ID: 15193903
 
Study Design:
Cross-Sectional Study
Class:
D - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
  • The purpose was to assess current dietary patterns of older adults with hypertension selected from a sample of rural elderly persons, compare them with the patterns of older adults without hypertension and describe their specific hypertension-related food group patterns
  • This study also compares the nutrient and food group intakes of the sample to current recommendations.
Inclusion Criteria:
  • Participants were a subset of the Geisinger Rural Aging Study (GRAS)
  • 200 persons were randomly selected for intensive nutrition assessment from the larger GRAS cohort; 180 completed all five 24-hour dietary recalls and were included in the analyses
  • Those participants who self-reported hypertensive conditions and had at least one anti-hypertensive medication prescribed were assigned to the hypertension group (N=90)
  • Those who did not self-report a hypertensive condition nor had an antihypertensive prescribed were then assigned to the control group (N=90).
Exclusion Criteria:
No exclusion criteria were reported.
Description of Study Protocol:

Recruitment

  • The recruitment methodology is not reported in this study. Investigators direct reader to details concerning the larger cohort (GRAS) found in the citation: Ledikwe JH, Smiciklas-Wright H, Mitchell DC et al, Nutritional risk assessment and obesity in rural older adults: a sex difference. Am J Clin Nutr. 1997; 66: 819-828.
  • All GRAS participants were enrolled in a Medicare risk program administered through a not-for-profit health maintenance organization.  

Design

Cross-sectional study

Blinding Used

Not clear as to who did the analyses of nutrient intake data and whether any blinding occurred.

Statistical Analysis

  • Differences in dietary intake between the older adults with hypertension and the control group were compared by T-tests
  • Differences between groups in demographic and health-related characteristics were examined using chi-squared analysis
  • A P-value of 0.05 or less was considered statistically significant.
Data Collection Summary:

Timing of Measurements

  • Baseline measurements taken during a home visit: Patient self-reporting of hypertensive condition, demographic information and disease states via interview; medication prescriptions reviewed, measured height and weight and BMI obtained 
  • Food and nutrient intake were measured using five 24-hour recalls conducted by telephone over the year following the home visit
  • Interviewers called participants to conduct a dietary recall every other month for 10 months following the home visit
  • Home visits and recalls were staggered throughout the year to reduce seasonal bias. 

Dependent Variables

Diagnosis of hypertension (yes or no) as per patient self-report and confirmed by anti-hypertensive medications obtained a baseline home visit by trained interviewer.

Independent Variables

  • Nutrient data: Averaged across the five 24-hour recalls collected to obtain mean energy, fat, calcium, magnesium, potassium and sodium intakes
  • Recalls were conducted by trained staff at the Pennsylvania State Diet Assessment Center, using the computer-assisted Nutrition Data System (NDS; version 2.6, nutrient database version 12, food database 27. Nutrition Coordinating Center, University of Minnesota, Minneapolis, MN. Release data, 1996)
  • Food group consumption patterns: The NDS summary file data containing each food consumed were edited to analyze for food groups allowing the identification of specific food. The contribution of each food subgroup was calculated for each nutrient for participants with hypertension.
Description of Actual Data Sample:

Initial N

200 randomly selected for intensive nutrition assessment from the larger GRAS cohort.

Attrition (final N)

  • N=180; 44% male, with hypertension (N=90) and without hypertension (N=90)
  • Of the 20 who did not complete the dietary recalls, one was excluded due to poor cognitive function, six for depression, 11 withdrew, one died and one had no data for hypertension status
  • Subset did not differ significantly from the the larger GRAS cohort in demographic or anthropometric characteristics and serum albumin and cholesterol
  • Participants in this subset were less likely to have a poor appetite or to need assistance with bathing, traveling and food preparation, compared to those in the larger cohort, but these differences were quite small.

Age

Both groups had a mean age of approximately 73 years (P=0.991).

Ethnicity

All participants (N=180) were non-Hispanic white people.

Other Relevant Demographics

  • 44% of both groups were male (P=1.00)
  • More than three-quarters had a least a high school degree (P=0.615) and most (over 76%) were married (P=0.867)
  • Participants with hypertension (N=90) were more likely to report having some form of cardiovascular disease (P=0.047)
  • There were no significant differences between groups in prevalence of high serum lipids or triglycerides (P=0.454), non-insulin dependent diabetes mellitus (P=0.118), gastrointestinal disease (P=0.594), liver disease (P=0.104), kidney disease (P=0.295) or osteoporosis (P=0.225)
  • The Hypertension Group were more likely to report being on special diet (P<0.001) and also took more medications than controls (P<0.001).

Anthropometrics

The Hypertension Group had a higher BMI (P=0.002) than the controls. 

Location

Rural central Pennsylvania.

Summary of Results:

 

Variables

Hypertension Group
Mean and Standard Deviations

Control Group
Mean and Standard Deviations

Statistical Significance of Group Difference

Nutrient Data

Energy (kcal)

1,500±481

1,686±487

P=0.011

Calcium (mg)
664±263 629±298
P=0.492
Magnesium (mg)
241±82
258±85
P=0.184
Potassium (mg) 2,443±722
2,541±726
P=0.367
Sodium (mg)    2,540±938 2,962±969 P=0.003
Food Groups (servings) Fruits 1.8±1.4 1.8±1.0 P=0.924
Vegetables 2.6±1.1 2.6±1.0 P=0.728
Dairy 1.9±1.1 2.1±1.5 P=0.361
Grains 5.0±2.1 5.9±1.8 P=0.006
Meat 1.8±0.8 2.0±0.9 P=0.037

Fats, Oils, Sweets

5.1±3.3

5.7±3.3

P=0.249

Other Findings

  • Calcium, magnesium and potassium intakes were not significantly different between the two groups
  • Both the treatment and control groups ate substantially below the recommended levels of these micronutrients and mirrored other findings from large national survey data for adults 60 years and older
  • Calcium was about half of the recommended level, with higher fat dairy foods being the greatest source in the diet
  • Magnesium-rich food sources (beans, nuts and seeds, fish and seafood) were eaten by less than half of the participants, with the exception of cereals
  • The participants did not achieve the recommended 3,500mg of potassium per day by the Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation and Treatment of High Blood Pressure
  • Reductions in energy and sodium intake among the treatment group reflect dietary changes that may have occurred secondary to the diagnosis of hypertension
  • Of the Hypertension Group, about two-thirds consumed citrus, melons and berries as well as fruit juices. Fruit juices were the greatest source of calcium after dairy foods.
  • Most participants are dark green leafy and deep yellow vegetables such as broccoli, lettuce and carrots
  • Almost everyone ate starchy vegetables (mainly corn, potatoes and peas)
  • Beans contributed the most magnesium and potassium to the diets but were consumed in the form of baked beans.
  • All participants ate breads and most ate cereals
  • Pancakes, waffles and French toast were eaten less often, but contributed the greatest amount of sodium in the diets.
Author Conclusion:
  • Findings in this study indicated that intake of calcium, magnesium and potassium intakes were below currently recommended levels
  • Participants consumed fewer servings of fruits and vegetables and more dairy servings than non-Hispanic white people 60 years and older participating in other dietary surveys; neither group met recommendations published in the Food Guide Pyramid nor the DASH Diet 
  • Investigators propose a number of changes in the food intake that could result in a more prudent, heart-healthy diet for the older adults with hypertension in this study. The recommendations include adding a serving of dairy products each day, avoiding processed meats to decrease sodium intake, choosing lower sodium vegetable sauces and juices, substituting low-fat dairy foods for whole milk products, adding calcium-fortified juices and increasing dark green leafy vegetables. 
Funding Source:
Government: USDA
Reviewer Comments:
  • The investigators were able to answer their primary research question as to whether the dietary consumption patterns of elderly patients with hypertension were significantly different than those without hypertension, using an observational study design
  • Obtaining blood pressure measurements, rather than relying on patient self-reporting may strengthen the assignment of participants to the respective groups and perhaps the clinical outcomes
  • If a repeated-measures design was used to evaluate dietary patterns and nutrient intake, rather than calculating an average nutrient intake, it may have been able to identify fluctuations in dietary consumption worthy of further exploration
  • Concerns could also be raised about the drawbacks of self-reporting dietary intake, especially among this population group
  • Lastly, the sample studied was not ethnically diverse and may impact the ability for generalizing these results to the larger population. 
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
  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) N/A
 
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
  1.2. 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? ???
  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? ???
  2.2. Were criteria applied equally to all study groups? ???
  2.2. Were criteria applied equally to all study groups? ???
  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? No
  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) 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.) Yes
  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? No
  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
4. Was method of handling withdrawals described? 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%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? ???
  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? ???
5. Was blinding used to prevent introduction of bias? ???
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  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.) N/A
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? ???
  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
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? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? Yes
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? ???
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? 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? No
  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? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? No
  7.5. Was the measurement of effect at an appropriate level of precision? ???
  7.6. Were other factors accounted for (measured) that could affect outcomes? No
  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
  8.2. 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
  8.5. 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
  8.7. 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? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes