EAL

HD: Effectiveness of Nutrition Intervention Methods (2010)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

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