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Health Disparities

HD: Effectiveness of Nutrition Intervention Methods (2010)

Citation:

Elmer P, Obarzanek E, Vollmer W, Simons-Morton D, Stevens V, Young D, Lin P, Champagne C, Harsha D, Svetkey L, Ard J, Brantley P, Proschan M, Erlinger T, Appel L. Effects of comprehensive lifestyle modification on diet, weight, physical fitness, and blood pressure control: 18-month results of a randomized trial. Ann Intern Med. 2006 April 4; 144 (7): 485-495.

PubMed ID: 16585662
 
Study Design:
Randomized Controlled Trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To compare the 18-month effects of two multi-component behavioral interventions vs. advice-only on hypertension status, lifestyle changes, and blood pressure.

Inclusion Criteria:
  • Generally healthy adults, age 25 or older
  • Pre-hypertension or stage 1 hypertension
  • Systolic blood pressure of 120mm to 150mm Hg
  • Diastolic blood pressure 80mm to 95mm Hg
  • Not taking anti-hypertensive medication.
Exclusion Criteria:
  • Body mass index less than 18.5kg per m2 or greater than 45.0kg per m2
  • Use of hypertensive drugs or drugs that affect blood pressure
  • Joint National Committee VI (JNC VI) risk category (organ transplantation or diabetes)
  • Use prescription weight-loss medications
  • Previous cardiovascular event, congestive heart failure or angina
  • Cancer
  • Consumption of more than 21 alcoholic drinks per week.
Description of Study Protocol:

Recruitment

  • Specific methods varied between four clinical sites
  • Direct mailings, radio and newspaper advertising, and networking in specific communities
  • Target recruitment methods were used to ensure representation of clinically important subgroups, particularly African-Americans.

Design

Random assignment of participants to one of three groups.

Blinding used

  • All clinic measurement staff were blinded to treatment assignment
  • All intervention staff were blinded to clinic measurements.

Intervention  

  • An intervention that that targeted established, guideline-recommended lifestyle recommendations
  • An intervention that targeted established recommendations and added in the DASH dietary pattern
  • The intervention format, contact pattern, and behavior change strategies for the two interventions were identical.
    • During the first six months, participants attended 14 groups sessions and four individual sessions
    • During months seven to 18, participants attended monthly group sessions and three individual counseling sessions.
  • Interventions provided by master’s degree-level trained counselors (including dietitians and health educators trained in behavioral methods).
Data Collection Summary:

Timing of Measurements

Initial, three-month, six-month and 18-month assessment.

Dependent Variables

  • Hypertension status: Blood pressure was assessed at each measurement
  • Nutrient intake: Obtained from two 24-hour dietary recalls; collected at baseline, six months and 18 months by telephone interview. Intake of nutrients and food groups were calculated using the Nutrition Data System for Research.
  • Sodium and potassium intake: Urinary excretion of sodium was obtained from 24-hour urinary collections at baseline and at six and 18 months
  • Weight: Measured with participants wearing light indoor clothing, no shoes
  • Cardiorespiratory fitness: Assessed using a two-stage, 10-minute sub-maximal treadmill exercise test
  • Physical activity: Seven-day, interviewer-administered physical activity recall was used to assess energy expenditure from physical activity.

Independent Variables

  • Established Group: Multi-component behavioral intervention that promoted increased physical activity, weight loss and reduced sodium intake
  • Established + DASH: Multi-component behavioral intervention that promoted increased physical activity, weight loss, reduced sodium intake and added the Dietary Approaches to Stop Hypertension (DASH) diet.

Control Variables

Advice-only Group: Received advice to follow the National High Blood Pressure Education Program lifestyle recommendations for blood pressure control.

Description of Actual Data Sample:
Variable
Advice-Only Group
(N=273)
Established Group
(N=268)
Established + DASH
(N=269)
Age (SD)
49.5 (8.8)
50.2 (8.6)
50.2 (9.3)
Race or ethnicity, (percentage)
 African-American
36.6
37.3
29.4
Non-Hispanic white 
61.2
60.8
67.3
Others
2.2
1.9
3.3
Women (percentage)
63.0
64.9
57.2
Mean BMI (SD) kg/m2
32.9 (5.6)
33.0 (5.5)
33.3 (6.3)

 

Summary of Results:
Variables
Advice-Only Group (A)
Established Group (B)
Established + DASH (C)
Pairwise Comparison
Statistical Significance of Group Difference
Prevalence of Hypertension (percentage)         Difference from baseline at 18 months
 
Baseline
38
36
38
B vs. A
0.83 (0.67-1.04)
 
Six months
26
17
12
C vs. A
0.77 (0.62-0.097)
  18 months
32
24
22
C vs. B
0.93 (0.075-1.15)
Nutrient Intake          
Mean Fruit and Vegetables
(N=248)
Servings per day
(N=237)
Servings per day
(N=243)
Servings per day
Pairwise Estimate (95% Cl)
  Baseline
4.4 (2.3)
4.6 (2.3)
4.7 (2.5)
B vs. A
-0.1 (-0.5-0.4)
 
Change at six months
0.5 (2.8)
0.5 (2.6)
3.0 (3.6)
C vs. A
2.6 (2.2-3.1)
 
Change at 18 months
0.3 (2.7)
0.1 (2.7)
2.8 (3.4)
C vs. B
2.7 (2.2-3.2)
Mean Dairy          
  Baseline
1.6 (1.2)
1.6 (1.3)
1.7 (1.2)
B vs. A
-0.2 (-0.4-0.0)
  Change at six months
0.1 (1.6)
-0.2 (1.5)
0.5 (1.6)
C vs. A
0.4 (0.2-0.6)
  Change at 18 months
0.0 (1.3)
-0.2 (1.5)
0.4 (1.5)
C vs. B
0.6 (0.4-0.8)
Mean Total Fat Percentage of kcal Percentage of kcal Percentage of kcal    
  Baseline
32.7 (7.2)
33.5 (8.0)
33.2 (7.7)
B vs. A
-1.5 (-2.8 to -0.1)
  Change at six months
-1.0 (7.9)
-3.9 (9.8)
-9.5 (9.5)
C vs. A
-6.0 (-7.4 to -4.7)
  Change at 18 months
-1.0 (8.6)
-3.0 (9.7)
-7.4 (8.9)
C vs. B
-4.6 (-6.0 to -3.2)
Saturated Fat          
 
Baseline
10.9 (3.3)
10.9 (3.1)
10.9 (3.0)
B vs. A
-0.6 (-1.1-0.0)
  Change at six months
-0.4 (3.9)
-1.5 (4.0)
-3.3 (3.9)
C vs. A
-2.3 (-2.8 to -1.8)
  Change at 18 months
-0.6 (3.8)
-1.1 (3.7)
-2.9 (3.4)
C vs. B
-1.7 (-2.3 to -1.2)
Mean kcal Intake          
 
Baseline
1,917 (622.7)
1,928 (590.6)
1,996 (652.1)
B vs. A
-130 (-271 to -44)
  Change at six months
-169 (638.8)
-316 (535.5)
-261 (590.8)
C vs. A
-95 (-181 to -10)
  Change at 18 months
-147 (596.7)
-281 (519.5)
-284 (637.0)
C vs. B
35 (52-122)
Mean Urinary Sodium Excretion N=233mmol per 24 hours N=223mmol per 24 hours N=214mmol per 24 hours    
 
Baseline
173.2 (69.5)
165.4 (70.1)
 
177.3 (80.0)
 
B vs. A
-16.7 (-30.3 to -3.2)
 
  Change at six months
-20.6 (71.6)
-31.6 (74.7)
-32.6 (78.1)
C vs. A
-15.4 (-29.1 to -1.7)
  Change at 18 months
-5.6 (89.8)
-18.4 (83.3)
-24.5 (85.2)
C vs. B
1.3 (-12.6-15.2)
Urinary Potassium Excretion (mean) N=233mmol per 24 hours N=223mmol per 24 hours N=214mmol per 24 hours    
 
Baseline
66.9 (28.1)
 
66.6 (23.9)
 
68.1 (27.0)
 
B vs. A
2.7 (-2.2-7.6)
 
  Change at six months
-1.3 (28.7)
0.9 (22.3)
19.3 (32.1)
C vs. A
12.7 (7.8-17.7)
  Change at 18 months
-2.5 (26.9)
0.2 (30.1)
9.6 (30.4)
C vs. B
10.0 (5.0-15.0)
Mean Weight N=241 N=235 N=241    
 
Baseline
96.0 (17.2)
 
95.7 (17.6)
98.6 (19.1)
 
B vs. A
-2.2 (-3.3-1.1)
 
  Change at six months
-1.1 (3.2)
-4.9 (5.5)
-5.8 (5.8)
C vs. A
-2.7 (-3.8-1.6)
  Change at 18 months
-1.5 (5.0)
-4.3 (7.4)
-4.3 (7.4)
C vs. B
-0.5 (-1.6-0..6)
Mean Fitness N=233 N=225 N=225    
 
Baseline beats per minute
129.8 (14.6)
 
130.5 (14.1)
 
130.0 (14.5)
 
B vs. A
-0.8 (-2.7-1.2)
 
  Change at six months beats per minute
-5.3 (9.7)
-8.0 (11.1)
-9.0 (10.7)
C vs. A
-2.1 (-4.0 to -0.1)
  Change at 18 months beats per minute
-7.4 (10.4)
-8.2 (11.2)
-9.5 (11.0)
C vs. B
-1.3 (-3.3-0.6)
Mean Physical Activity N=242kcal per kilogram N=232kcal per kilogram N=240kcal per kilogram    
 
Baseline
33.7 (2.5)
 
33.8 (2.6)
 
33.6 (2.4)
 
B vs. A
-0.2 (-0.7-0.3)
 
  Change at six months
0.3 (2.9)
0.4 (2.9)
0.6 (2.4)
C vs. A
0.1 (-0.3-0.6)
  Change at 18 months
0.6 (3.6)
0.3 (2.6)
0.8 (3.4)
C vs. B
0.3 (-0.1-0.8)

Other Findings

Unanticipated findings were the extent of lifestyle changes in the participants in the Advice Group, who made some lifestyle changes at both six and 18 months.

Author Conclusion:

Individuals with pre-hypertension and stage 1 hypertension can make and sustain, during a period of 18 months, multiple lifestyle modifications that can control blood pressure and reduce the risk of chronic disease.

Funding Source:
Government: NHLBI
Industry:
Kaiser Permanente Northwest
Other:
University/Hospital: University of Maryland, Duke University Medical Center, Pennington Biomedical Research Center, University of Alabama, Johns Hopkins Medical Institutions
Reviewer Comments:

Intensive counseling on lifestyle change strategies can have a long-term effect on chronic disease risk factors.

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
  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
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
 
Validity Questions
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
2. Was the selection of study subjects/patients free from bias? N/A
  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? Yes
  2.2. Were criteria applied equally to all study groups? 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? Yes
3. Were study groups comparable? N/A
  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? 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
4. Was method of handling withdrawals described? ???
  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? 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
  5.3. 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
  5.5. 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? Yes
  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? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  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? 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
  7.2. 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? 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? 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? N/A
  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
  8.4. 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)? Yes
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? 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
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
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? N/A
  10.2. Was the study free from apparent conflict of interest? Yes