PWM: Eating Behaviors of Children (2006)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To examine demographic, behavioral and dietary correlations of frequency of fast food restaurant use in a community-based sample of 4,746 adolescent students.
Inclusion Criteria:
Students in grades seven through 12, who were enrolled in participating schools, had parental consent and were in attendance on the day of data collection.
Exclusion Criteria:
Description of Study Protocol:

A survey was administered to students in classrooms at 31 secondary schools in a large metropolitan area in Minnesota, United States. Height and body weight were measured.

Survey Included

  • Frequency of food restaurant use (FFFRU): Measured by single question, "In the past week, how often did you eat something from a fast food restaurant?" with response categories from "never" to "five or more times"
  • Dietary intake: Youth Adolescent Questionnaire; modified food frequency questionnaire previously used with youths aged nine to 18 years, with one year of moderate reproducibility (average correlations for 10 nutrients and calories was 0.55, range 0.24-0.92
  • Demographic and environmental: Self-reported; including assessing family meal frequency with one item, “During the past 7 days, how many times did all or most of your family living in your house eat a meal together?”
  • Family variables: Parental education, employment, student eligibility for free or reduced lunch and family receipt of public assistance, were combined to create a three-level socioeconomic status (SES) variable of low, middle and high.
  • Home availability of “healthy foods”: Measured by summing responses (never, sometimes, usually or always) to four questions about the availability of fruit, vegetables and milk (Cronbach A=0.63).
  • Home availability of “unhealthy foods”: Measured by summing responses to four questions about availability of "junk food" (potato chips, chocolate or candy and soft drinks) (Cronbach A=0.80)
  • Behavioral: Self-administered questionnaire addressed perceived benefits and barriers to healthy eating and self-efficacy (Cronbach A=0.60-0.83).
  • Frequency of eating out: Measured by the sum of the number of times students reported eating breakfast, lunch, dinner or snacks prepared away from home.
  • Frequency of snacking (“yesterday”) and use of prepared foods such as frozen, canned or microwave dinners (per week): Self-reported.
  • Anthropometric: Height and weight (measured). Overweight defined as =95th percentile for age and gender.
  • Physical activity: Self-reported; Three questions about number of hours per week spent in strenuous, moderate and mild exercise.
  • Television viewing: Self-reported number of hours on weekday and weekends.

Statistical Analyses

  • All analysis conducted separately by gender.
  • Bivariate associations between frequency of fast food restaurant use (FFFRU) and demographic variables (grade, race, SES, free or reduced lunch).
  • Mixed model regression analyses were used to group variables within personal, behavioral and environmental categories. Demographic variables that were significantly associated with fast food restaurant use were included as covariates in separate regression models examining associations between fast food restaurant use and each of the other variables.
  • Post hoc mean comparisons for significant main effects from the mixed model regressions were adjusted for multiple comparisons using the Bonferroni correction.
Data Collection Summary:

Independent

  • Frequency of fast food restaurant use.

Dependent Variables

  • School
  • Grade
  • Gender
  • Race
  • SES
  • BMI.

Confounding

  • Total energy intake, grade, race, school, socioeconomic status and body mass index.
  • Nutrients adjusted for total energy intake (except for variables total energy and percentage of energy from fat).
Description of Actual Data Sample:
  • N: 4,746
  • Age: Grades seven to 12
  • Ethnicity: Not specified
  • Location: Minnesota, USA.
Summary of Results:

Eating Out Results

  • FFFRU was not significantly associated with overweight status among males or females.
  • However, BMI was significantly lower among males who reported eating at fast food restaurants three or more times per week, compared with those reporting less frequent visits to fast food establishments (P<0.05).

Other Results

  • Overall, 75% of students were reported eating at a fast food restaurant during the previous week of the survey.
  • Compared to those who reported never eating at a fast food establishment during the previous week, total energy intake was 40% higher among males and 37% higher among females; percentage of energy from fat was 9% higher among males and 13% higher among females who reported three or more visits to a FFFRU during the past week.
  • In addition to a positive association with intake of total energy and percentage of energy from fat among both males and females, FFFRU had a positive association with intake of soft drinks, cheeseburgers, pizza and French fries (P<0.05). FFFRU was found to have an inverse association with daily intake of milk, fruits and vegetables (P<0.05).
  • Among males and females, frequency of eating out, number of snacks consumed the previous day and eating ready-made foods were significantly positively associated with FFFRU (all P<0.0001). The pattern of association was dose-related, with increasing eating out, snacking and eating ready-made foods associated with more frequent FFFRU during the past week.
  • Among males and females, FFFRU was significantly associated with availability of “unhealthy foods” in the home (P<0.0001). Family meal frequency and availability of  “healthy foods” at home were not significantly associated with FFFRU.
Author Conclusion:

In this study, there was no significant association between FFFRU and obesity, although FFFRU is significantly associated with energy and fat intake.

In males who visited fast food establishments three or more times per week, compared with males who visited fast food restaurants two or fewer times per week, BMI was significantly inversely associated with FFFRU.

In females, BMI was not associated with FFFRU. This finding warrants further study. Additional studies are needed to understand the potential contribution of FFFRU to excess weight gain during young adulthood.

FFFRU was found to be associated with a less nutritious diet and poorer food choices among adolescents. FFFR was associated with significantly lower intakes of fruit, vegetables, grains, and milk and with higher intakes of soft drinks, cheeseburgers, pizza and French fries.
Funding Source:
University/Hospital: University of Sheffield (UK)
Reviewer Comments:

Cross-sectional design does not allow for cause and effect conclusions.

Study Weaknesses

  • Single-item measure of fast food intake.
  • Lack of measures of food choices at fast food establishments.
  • Mismatch between the time frame covered by the food frequency dietary assessment (past year) and the fast food measure (past year).
  • Not known if the past seven days was representative of participants’ typical FFFRU.
  • Self-defined snacks
  • Meals self-reported; no defined time span; what may be breakfast to one participant might be lunch to another
  • Frequency of eating out span or what is away from home is not defined.
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) N/A
  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) N/A
 
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? No
  2.2. Were criteria applied equally to all study groups? No
  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) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  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? 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? 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? No
  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? N/A
  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? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  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? 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? N/A
  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)? 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? No
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