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Citation:

Mangunkusumo RT, Brug J, de Koning HJ, van der Lei J, Raat H. School-based internet-tailored fruit and vegetable education combined with brief counselling increases children's awareness of intake levels. Public Health Nutr. 2007 Mar;10(3):273-9.


PubMed ID: 17288625
Study Design:
Randomized Controlled Trial
Class:
A - Click here for explanation of classification scheme.
POSITIVE: See Research Design and Implementation Criteria Checklist below.
Research Purpose:

To evaluate the effectiveness of a two-component intervention on fruit/vegetable intake by comparing a group receiving the intervention with a control group as well as to explore the effects on potential determinants of intake levels and self-reported intake as important initial steps towards behavioral change and measure the level of exposure to the intervention.

Inclusion Criteria:
  • Attendance at invited elementary schools and classes in the Netherlands
  • Enrollment in seventh grade
  • Signed parental consent.
Exclusion Criteria:
  • Not seventh grade student at invited elementary schools and classes in the Netherlands 
  • Lack of signed parental consent.
Description of Study Protocol:

Recruitment

  • Recruited from rural (Harderwijk) and urban (Vlaardingen) area elementary schools in the Netherlands

Design:  Randomized controlled trial

Students from 30 seventh grade classes, 16 classes from Harderwijk region and 14 classes from Vlaardingen region, were randomly assigned (within nurses) to the intervention or control group. Both groups completed during school hours an Internet-administered baseline questionnaire and about three months later a similar post-test questionnaire on potential determinants and intake related to fruit/vegetables as well as demographic characteristics. The intervention group received Internet tailored advice for children followed by Internet-supported brief dietary counseling by the nurse in the presence of at least one parent. The control group did not receive any dietary advice or counseling. 

Blinding used: Parents and children blinded to group assignment 

Intervention

  • Combination of Internet-tailored nutrition advice for the children followed by Internet-supported brief dietary counseling by the nurse in the presence of at least one parent
  • Aim of Internet-tailored advice was to increase knowledge of recommended intake levels, increase awareness of personal intake levels and stimulate children's liking of fruits and vegetables and their availability in the home
  • Dietary counseling by the nurse to parent and child focused on increasing the child's knowledge about recommended intake levels, increasing awareness of personal intake levels and motivating the child to eat sufficient fruits and vegetables and/or discussing any barriers in order to increase self-efficacy for behavior change 

Statistical Analysis

  • Multiple logistic regression of treatment condition to test for equality of groups at baseline
  • Intent to treat analyses conducted for all effect analyses
  • Multilevel analyses with random intercepts were conducted
  • Regression coefficient used to describe effect size
  • 95% confidence interval used to determine statistical significance.
Data Collection Summary:

Timing of Measurements

  • Fruit and vegetable intake measured at baseline and three months later
  • Potential determinants of dietary intake were assessed at baseline and three months later 

Dependent Variables

  • Fruit intake as measured by food frequency questionnaire and questions regarding number of days fruit was consumed in previous week and number of pieces of fruit consumed per day on such days
  • Vegetable intake assessed by pre-coded 24-hour recall based on previous day's intake
  • Behavioral determinants as measured by questionnaire

Independent Variables

  • Level of nutrition counseling
    • Internet-tailored dietary advice and Internet-supported brief dietary counseling
    • No advice or counseling provided

Control Variables

  • Age
  • Gender
  • Family status
  • Ethnicity

 

Description of Actual Data Sample:

Initial N: 486 children (229 boys, 257 girls)

Attrition (final N): 469 children

Age: Intervention group 10.3 ± 0.5 years, control group 10.3 ± 0.5 years

Ethnicity: Intervention group 88.6% Dutch background, control group 84.6% Dutch background

Other relevant demographics

  • Family status (two parent family)
    • Intervention group 91.3% of children from two parent family
    • Control group 95.8% of children from two parent family 

Anthropometrics: No anthropometrics measured and no significant differences between groups at baseline

Location:  Harderwijk and Vlaardingen areas of The Netherlands.

 

Summary of Results:

Key Findings

  • Fruit and vegetable intake did not differ significantly between the intervention and control groups
  • Children in the intervention group were three times more likely to be aware of their personal inadequate fruit intake level and almost three times more likely to know the recommended vegetable levels at post-test then children in the control group
  • Awareness of inadequate vegetable intake and knowledge of the fruit recommendation showed odds ratios in favor of the intervention group but not significant
  • 84% of children reported reading both sets of advice completely, 8% read part of the advice, 5% read only the fruit or only the vegetable advice and 3% had read nothing
  • Nurses indicated that most of the counseling sessions concluded with encouraging the child's self-efficacy to change behavior (about 42%) and with stimulating goal setting (about 21%).

Variables

Intervention group

n=263

Control group

n=223

Odds ratio

95% confidence interval

Fruit frequency (servings per day)

1.1 ± 0.7

1.2 ± 0.7

Not applicable

 

Usual daily fruit intake (%)

32

34.7

0.82 (0.45, 1.49)

Knowledge of recommendations, correct amount (%)

57.1

50.7 

1.3 (0.85, 1.99)

Awareness of inadequate intake previous week (%) 30.8 13 3.04 (1.75, 5.26)
Self-efficacy: daily fruit intake achievable (%) 76 79.5 0.83 (0.52, 1.31)
Liking many types of fruit (%) 73.4 76.7 0.73 (0.38, 1.39)
Availability, always fruit at home (%) 74.5 77.6 0.89 (0.53, 1.51)

 

Variables

Intervention group

n=263

Control group

n=223

Odds ratio

95% confidence interval

24 hour recall vegetable intake (grams)

76.9 ± 68.7

74.9 ± 69.7

Not applicable

 

Usual daily vegetable intake (%)

28.1

28.7

0.81 (0.44, 1.47)

Knowledge of recommendations, correct amount (%)

47.1

21.4 

2.71 (1.79, 4.11)

Awareness of inadequate intake previous day (%) 31.9 21.4 1.42 (0.87, 2.34)
Self-efficacy: daily vegetable intake achievable (%) 60.5 59.5 0.98 (0.58, 1.66)
Liking many types of vegetables (%) 38.8 41.7 0.92 (0.6, 1.42)
Availability, usually two or more types of vegetables at dinner (%) 52.5 55.2 0.96 (0.63, 1.44)


 

Author Conclusion:

This study indicated that an intervention combining Internet-tailored nutrition advice with dietary counseling by a nurse among elementary-school children resulted in better knowledge of the recommended vegetable intake levels and awareness of inadequate fruit intake but no effects were found regarding actual intake levels. To induce changes in intake levels, more comprehensive interventions may be needed.

Reviewer Comments:

Authors note the following limitations:

  • Possible response bias due to self-administered questionnaires
  • That only one outcome measurement (3 months after the baseline measurement) was applied may be considered a limitation
     

Research Design and Implementation 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 nutrition or dietetics practice?
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)
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 used? (Concurrent preferred over historical controls.)
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 or cross-sectional 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. Criterion may not be applicable in some cross-sectional studies.)
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?
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?
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)?
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?
Yes
  10.2. Was the study free from apparent conflict of interest?
Yes
 
 

Copyright American Dietetic Association (ADA).