EAL

AWM: Nutrition Education (2006)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To describe the intervention in a clinical trial examining the effect of a plant-based diet on breast cancer recurrence, and to report baseline to 12-month dietary change and investigate whether cooking-class attendance influenced adherence to the study's dietary targets.

Inclusion Criteria:

Women who had been treated for stage I, II or IIIA invasive breast cancer. All were recruited within 4 years of diagnosis, had completed cancer treatment, and were clinically free of disease at the time of randomization.

Exclusion Criteria:

Not specifically mentioned.

Description of Study Protocol:

Recruitment

Participants from WHEL study (3088 women).

Design

Descriptive analysis of baseline and 12-month dietary intake data and other variables in a subcohort of participants in the WHEL study.

Blinding used (if applicable)

Not applicable.

Intervention (if applicable)

Telephone counseling, complemented by an orientation meeting, cooking classes and newsletters.

Statistical Analysis

Mean intake for vegetables, vegetable juice, fruit, fiber and fat were calculated. Percentage of women meeting select Healthy People 2010 objectives were tabulated. A graph showing baseline and 12 month WHEL Adherence Score as a function of the number of cooking classes attended during the first 12 months of intervention was prepared. Using linear regression, the WHEL Adherence Score at 12 months was modeled as a function of the number of cooking classes attended during the first 12 months.

Data Collection Summary:

Timing of Measurements

Measurements taken at enrollment and after 12 months.

Dependent Variables

Change in intake of vegetables, vegetable juice, fruit, fiber and fat
Cooking classes attended - 12 monthly classes taught by RD
Overall dietary adherence measured through WHEL Study Adherence Scoring System which uses dietary data averaged from recalls and weighted to reflect study emphasis on vegetable intake
Height, weight, BMI measured using standard procedures

Independent Variables

Dietary intervention and adherence measured with 4 scheduled 24-hour dietary recalls over the telephone on randomly selected days stratified for weekend vs weekday over 3 week period. Participants taught to estimate food intake with food models, measuring cups and spoons and a multipass recall protocol

Control Variables

Description of Actual Data Sample:

Initial N: 739 women (subcohort of 3088 in WHEL study), adherent to telephone counseling. This subsample had completed the recommended 15 - 23 counseling calls within the first 12 months of the intervention and had also completed their 12-month dietary recalls on protocol.

Attrition (final N): See above.

Age: Mean age at study entry was 54 years

Ethnicity: primarily non-Hispanic white (87%)

Other relevant demographics: Mean BMI: 26.7

Anthropometrics: Subsample did not differ significantly in ethnicity, education or age from rest of WHEL Study intervention group but did have lower BMI (26.7 vs 27.6, respectively)

Location: California, Arizona, Texas, Oregon

Summary of Results:

	Goal Intake	Baseline Mean +/- SEM	12 Month Mean +/- SEM	P-Value
Vegetables	5 svgs/day	3.9 +/- 0.1	5.4 +/- 0.1	<0.001
Vegetable Juice	4 svgs/day	0.1 +/- 0.02	2.6 +/- 0.1	<0.001
Total Vegetables	9 svgs/day	4.0 +/- 0.1	8.1 +/- 0.2	<0.001
Fruit	3 svgs/day	2.7 +/- 0.1	3.6 +/- 0.01	< 0.001
Fruit Juice	0 svgs/day	0.9 +/- 0.0	0.6 +/- 0.0	<0.001
Total Fruit	3 svgs/day	3.6 +/- 0.1	4.2 +/- 0.1	<0.001
Fiber	30 g/day	22.1 +/- 0.3	30.3 +/- 0.4	<0.001
Fat	20% of energy	27.7 +/- 0.3	21.7 +/- 0.3	<0.001

Other Findings

Median number of counseling calls completed was 19. Median number of cooking classes attended was 5 (with 17.2% attending no classes within the first 12 months of intervention and 23.3% attending 9 or more classes during this time period).

Total daily vegetable, vegetable juice, fruit and fiber intake increased significantly (P < 0.001), while fat decreased significantly (P < 0.001).

The percentage of women meeting the Healthy People 2010 fruit and vegetable objectives increased substantially.

Those who attended fewer than 5 cooking classes had mean baseline WHEL Adherence Scores under 300, those who attended between 5 - 10 classes had mean baseline WHEL Adherence Scores in the low 300s, and those who attended 11 or 12 classes had mean baseline scores in the mid-300s.

Overall dietary adherence was associated with increased cooking-class attendance (P for trend < 0.01).

Author Conclusion:

A multimodal approach to dietary modification, largely based on individualized telephone counseling, can substantially change the overall dietary pattern of women previously treated for breast cancer. The results of this study indicate that cooking-class attendance was associated with further improvement in dietary adherence beyond that achieved by telephone counseling alone. In summary, individualized, telephone-based dietary counseling, supplemented with cooking classes and other informational activities to reinforce and facilitate behavior change, is associated with increased vegetable, fruit and fiber intake and decreased fat intake. More importantly, these efforts can focus on the specific foods and overall dietary pattern that have been most consistently associated with reduced risk for chronic disease.

Funding Source:

Government:

NIH, National Cancer Institute

Not-for-profit

Foundation associated with industry:

Reviewer Comments:

Large sample size. WHEL Study Adherence Scoring System not necessarily a validated measure of adherence.

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?		Yes
	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?		Yes
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	N/A
	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.)	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?	Yes
	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?		N/A
	4.1.	Were follow-up methods described and the same for all groups?	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?	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
5.	Was blinding used to prevent introduction of bias?		N/A
	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?	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?	Yes
	6.6.	Were extra or unplanned treatments described?	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
7.	Were outcomes clearly defined and the measurements valid and reliable?		???
	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?	???
	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?		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
	8.4.	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)?	N/A
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	???
	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?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes