EAL

AWM: Nutrition Education (2006)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To test the effects of warning and information labels on consumption of fatty foods.

Inclusion Criteria:

None specifically mentioned.

Exclusion Criteria:

None specifically mentioned.

Description of Study Protocol:

Recruitment

Students in undergraduate psychology course.

Design

Randomized Controlled Trial.

Blinding used (if applicable)

Not used.

Intervention (if applicable)

Participants assigned to 1 of 3 groups: warning label, information label, and no label. Participants then rated how much they wanted to taste full-, reduced- and no-fat cream cheese, and they chose 1 type to eat. Participants were told that the study was about cream cheese evaluation.

Statistical Analysis

Study design was factorial, with variables of label condition, sex of participant, and type of cream cheese. The last variable involved repeated measures. MANOVA used to test whether labels influenced desire to taste cream cheese. ANOVA and nonparametric analyses used to test whether labels influenced which type of cream cheese participants selected to taste.

Data Collection Summary:

Timing of Measurements

Participants assigned to 1 of 3 groups based on label. Participants rated how much they wanted to taste each type of cream cheese, and they selected 1 type to eat.

Dependent Variables

Desire to taste each type based on 10-point Likert scale
Selection of cream cheese
Ratings of flavor, zest, texture, aftertaste, overall

Independent Variables

Cream cheeses: regular (full-fat), light (reduced fat) and fat-free, with labels of warning label ("In this product, 90% of the calories come from fat. Warning: The Surgeon General has determined that eating high fat food increases your risk of heart disease"), information label ("In this product, 90% of the calories come from fat") or no label.

Control Variables

Description of Actual Data Sample:

Initial N: 360 undergraduate psychology students, 180 men, 180 women

Attrition (final N): See above.

Age: Not reported.

Ethnicity: Not reported.

Other relevant demographics: Not reported.

Anthropometrics: Not reported.

Location: Iowa State University

Summary of Results:

Other Findings

People in the warning- and no-label groups wanted to taste the full-fat product more than those in the information-label group, t(354) =2.56, p < 0.05, d=0.27, and t(354) =1.72, p < 0.10, d= 0.18, respectively, although the latter comparison was not statistically significant. There was no difference between the warning label and no-label conditions.

Men wanted to taste the full-fat cream cheese more than women did, whereas women wanted to taste the reduced-fat and no-fat cream cheeses more than men, Fs(1,354) = 18.96, 9.07, and 42.16, respectively, all p < 0.05.

People in the warning- and information-label groups were less likely to eat the full-fat product than those in the no-label group, t(354) = 2.30, p < 0.05, d=0.24, and t(354) = 2.06, p < 0.05, d=0.22, respectively.

Women selected lower-fat cream cheeses more often than men did, F (1,354) = 49.01, p < 0.05, d=0.74. Overall, 49% of men selected high-fat cream cheese, 23% selected reduced-fat cream cheese, and 28% selected no-fat cream cheese. In contrast, 18% of women selected full-fat cream cheese, 25% selected reduced-fat cream cheese, and 57% selected no-fat cream cheese.

Author Conclusion:

In summary, information labels seem to be at least as effective as warning labels in influencing people to avoid unhealthy products, at least when the risk is credible and familiar. Although people don't mind being informed about the potentially harmful risks associated with products, they don't like to receive unwanted advice about how they should behave. Warning people about unhealthy products may only make them want the products more.

Funding Source:

University/Hospital:

Iowa State University

Reviewer Comments:

Questionnaire not tested for validity or reliability.

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?		???
	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?	???
	2.3.	Were health, demographics, and other characteristics of subjects described?	No
	2.4.	Were the subjects/patients a representative sample of the relevant population?	???
3.	Were study groups comparable?		???
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	No
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	???
	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?		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?	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?		No
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	No
	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.)	No
	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?	N/A
	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?	???
	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)?	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?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes