PWM: School-based Programs to Prevent Overweight (2006)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
A school health education and promotion program in Jeruselum for preventing chronic disease, in particular CVD.
Inclusion Criteria:
None provided
Exclusion Criteria:
None provided
Description of Study Protocol:

SEGEV program, acronym for Hebrew phrase “keep you body healthy”, the Israeli version of the American Health Foundation’s “Know Your body” Program.

Recruitment and school selection:

not described; stated that experimental schools chosen (not randomly selected)


  • 15-20 teaching hr/y taught by regular classroom teacher over 2-3 mo period (themes repeated each year, adjusted for specific age gps)
  • Includes student workbooks, teacher manuals, parent materials, individual health passports, and posters
  • Focuses on self-responsibility for health, positive self-concept, and health decision-making
  • Parent participation integral
  • 10 units: 
    • positive self-concept
    • external/internal body parts
    • prevention of communicable diseases
    • best food choices (2 units
    • prevention of dental disease
    • heart and lung health
    • physical activity
    • safety
    • decision making and prevention  of smoking & drug abuse
  • Reinforced with school and com-munity activities (e.g., health fair)
  • Control group:  received health knowledge & attitude questionnaires and referral for care if total cholesterol >180 mg/dl

Statistical Analysis:

  • 3-way ANOVA – to test differences in BMI at baseline between experimental vs. control groups, boys vs. girls, and Jewish vs. Arab children
  • 3-way ANOVA (using residual scores of BMI [analogous to z scores] - to test differences between groups at f/u
  • 2-way ANOVA – to test for differences in HDL at baseline between experimental vs. control groups, boys vs. girls (Jewish only due to technical problems with Arab samples)
  • 2-way ANOVA (using residual scores of HDL) – to test differences between groups at f/u
Data Collection Summary:

Timing of Measurements

Dependent Variables

  • Health knowledge (questionnaires)
  • Dietary habits (‘reports’)
  • Weight (measured)
  • Height (measured)
  • BP
  • Fasting blood lipids: total cholesterol, HDL, TG

Independent Variables

SEGEV program (see above)

Control Variables

Baseline BMI (for BMI assessments only)

Description of Actual Data Sample:

Original Sample: 829 children

8 experimental (chosen to represent cross-section of SES, religious & ethnic groups), 8 control schools (matched on ?)

Withdrawals/Drop-Outs: 423 children (51% attrition) had either moved, were absent from school on day of 2 y examination, or did not have parent’s signature on consent form (numbers for each reason not provided but stated that main reason is due to parent’s refusal to allow second blood test in 3rd grade)

Final Sample:  406 children (242 experimental, 161 control) [Note: BMI analysis based on sample size of 395 children with ‘accepted information’ – no description of what ‘accepted’ means)

7-9 y (1st grade at baseline, 3rd grade at follow-up)

Location:  Jeruselum, Israel

Duration:  2 y, 1983-1984 (state that preliminary results and that results on knowledge, attitude and dietary practice in publication, but no additional paper found on Pubmed)

Race/Ethnicity:  12 Jewish & 4 Arab schools; Baseline: 76% Jewish, 24% Arab; Follow-up: 81% Jewish, 19% Arab

SES:  Not described but see below.

Summary of Results:
  • No differences between groups on father’s and mother’s education, country of father’s birth, number of children in family, SES, or religion
  • No differences in BMI between experimental & control groups, but BMI was lower in Jewish children (15.75 + 1.49) than for Arab children (16.54 + 1.38) (p>.001)
  • Lower HDL by 3.4 mg/dl in experimental vs. control group (p<.05)
  • Higher total cholesterol by 11.2 mg/dl in experimental vs. control group (p<.001); also higher in girls than boys (p<.01), and in Jewish than Arab children (p<.001)


  • Lower BMI by 0.76 units (residual score or kg/m2?) in experimental vs. control group (p<.01) [presented results by ethnicity and gender, but did not describe which differences were statistically significant for these breakdowns]
  • Higher HDL by 3.42 mg/dl (or residual score?) in experimental vs. control group (p<.05)
  • Lower total cholesterol by 11.96 mg/dl in Arab experimental vs. Arab control group (p<.05?); no difference in Jewish children by group
  • No significant difference in total cholesterol after controlling for initial levels of total cholesterol and residual scores of HDL at f/u.

No statistical evaluation of intervention effect was done for BP and TY because low Pearson correlation coefficients between 1st and 3rd grades found.

Author Conclusion:
The initial results of our program indicate that changes in risk factors for CVD, such as serum TC, HDL, and BMI in children aged 7-9 years, are possible after a health education and promotion program in introduced in schools for a relatively short period of time
Funding Source:
Reviewer Comments:

Strengths: 2 y intervention

Limitations:  High attrition rate, failure to control for numerous potential confounding variables, unclear what diet recommenda-tions were made, no intention to treat analysis, no blinding of measurements, no inclusion or exclusion criteria provided, no description of teacher training on curriculum or how parents were involved in program, sample size varied for different measures without reasons provided, how schools selected and matched not clearly described.

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? ???
  2.3. Were health, demographics, and other characteristics of subjects described? ???
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
3. Were study groups comparable? No
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) ???
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? No
  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? No
  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.) ???
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? ???
4. Was method of handling withdrawals described? No
  4.1. Were follow-up methods described and the same for all groups? ???
  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? No
  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? ???
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? ???
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? ???
  5.5. In diagnostic study, were test results blinded to patient history and other test results? ???
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? No
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? No
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? ???
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? ???
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? No
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? ???
  6.6. Were extra or unplanned treatments described? ???
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? ???
  6.8. In diagnostic study, were details of test administration and replication sufficient? ???
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? No
  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? No
  7.7. Were the measurements conducted consistently across groups? ???
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? No
  8.1. Were statistical analyses adequately described and the results reported appropriately? No
  8.2. Were correct statistical tests used and assumptions of test not violated? ???
  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? No
  8.7. If negative findings, was a power calculation reported to address type 2 error? ???
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