NGHC: Childhood Nutrition and Advertising (2013)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

The purpose of this study was to investigate whether preschool children's taste preferences were influenced by branding from a heavily marketed source.

Inclusion Criteria:
  • Parents and children had to be a part of Head Start, a federally sponsored preschool program for low-income families
  • Informed consent was obtained from parents.
Exclusion Criteria:

Not described.

Description of Study Protocol:

Recruitment

Participants and their parents were recruited from six Head Start centers in San Mateo County, CA.

Design

Randomized controlled trial. The order of foods presented and placement of the McDonald’s-wrapped food on the left or right followed a predetermined random order for each child and each food.

Blinding Used

Research assistants were blinded; children sat at a table with a tray in front of an opaque screen and one research assistant sat behind the screen and could not see the child or tray but her arms could reach around the screen.

Intervention

Children tasted five pairs of identical foods and beverages in packaging from McDonald’s and matched but unbranded packaging and were asked to indicate if they tasted the same or if one tasted better.

Statistical Analysis

  • For the primary analysis, testing preferences across all foods combined were averaged to create a total preference score between -1 and +1 for each participant
  • A nonparametric Wilcoxon signed rank test was used to test the null hypothesis
  • In a secondary analysis, the null hypothesis was tested for each food or drink separately using a McNemar test
  • Statistical significance was set at a two-tailed alpha of less than 0.05
  • Spearman rank correlation for scaled variables, the Wilcoxon Mann-Whitney U-test for dichotomous variables and the non-parametric Kruskal Wallis test for categorical variables were also used.
Data Collection Summary:

Timing of Measurements

Trained research assistants asked participating children if they wanted to play a food tasting game. Children were told they did not have to play if they did not want to and they could stop any time.

Dependent Variables

  • Children were asked to indicate if they tasted the same or if one tasted better
  • Through a series of questions and food tastings, the research assistant asked the children to identify which foods were from McDonald's and if the McDonald's food tasted the same or different from the regular unbranded foods.

Independent Variables

  • Children tasted five pairs of identical foods and beverages in packaging from McDonald’s and matched but unbranded packaging
  • Communication in English or Spanish was appropriate
  • Children sat at a table with a tray in front of an opaque screen and one research assistant (RA1) sat behind the screen and could not see the child or tray but her arms could reach around the screen.

Control Variables

  • Parents completed a self-administered questionnaire in English or Spanish including their child's birth date, race or ethnicity, the number of television sets in their home, whether there was a television in the child's bedroom and the number of hours of television their child watched in a typical work week
  • Other questions parents answered were the frequency of which the television was on at their house for most of the morning, in the afternoon, during dinner and in the evening; if in the past week their child had asked them for any foods or drinks that he or she saw on television and how often their child ate food from McDonald's and other fast-food restaurants; and whether there were any toys from McDonald's in their home.
Description of Actual Data Sample:

Initial N

63 children.

Attrition (Final N)

63 children.

Age

Three- to five-year-old children (mean age was 4.6±0.5 years, range 3.5 to 5.4 years).

Ethnicity

  • 55.6% Latino or Hispanic
  • 1.6% African-American or black
  • 6.3% Asian or Pacific Islander
  • 1.6% Native American or Alaska Native
  • 12.7% white
  • 22.2% multi-ethnic or other.

Other Relevant Demographics

Not reported.

Anthropometrics

Not reported.

Location

San Mateo, CA.

Summary of Results:

Key Findings

  • The mean ± standard deviation total taste preference score across all food comparisons was 0.37±0.45 (median, 0.20; interquartile range, 0.00 to 0.80) and significantly greater than zero (P<0.001), indicating that children preferred the tastes of foods and drinks if they thought they were from McDonald's
  • Moderator analysis found significantly greater effects of branding among children with more television sets in their homes and children who ate food from McDonald's more often.
Author Conclusion:

The results from this study add evidence to support recommendations to regulate or ban advertising or marketing of high-calorie, low-nutrient foods and beverages or all marketing that is directed to young children. The findings also suggest a need for research on marketing in general and branding in particular.

Funding Source:
University/Hospital: Stanford University School of Medicine
Other: Robert Wood Johnson Foundation Generalist Physician Faculty Scholar Award
Reviewer Comments:
  • Participants and their parents were recruited from only six Head Start centers in San Mateo County, CA, limiting generalizability
  • The authors did identify some limitations:
    • First, they were unable to directly measure or manipulate the total marketing or product exposure for the entire first three to five years of life and multiple exposures to the brand cannot be disentangled
    • Second, they were unable to test how each individual direct or indirect exposure to McDonald's marketing, food, packaging, etc. influences a child's perceptions, but accepted these as a complex of both independent and interacting influences on emotions and perceptions about the brand.
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? No
  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? 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? No
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? 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? Yes
  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? 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? 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? 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? 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)? 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
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