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

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
  1. To assess whether a program of general health and nutritional education in school-children can also result in the control of overweight and obesity during a five-year period.
  2. To improve the level of risk factors for coronary heart disease in children through the control of hypercholesterolaemia, high blood pressure and obesity through a nutrition intervention program aimed at improving dietary habits.
Inclusion Criteria:

All school-children in an elementary school in Sezze Romano, aged 6-7 years at the initial examination in 1983.

BMI calculated for evaluation of body fatness in keeping with WHO recommendations.

None of final 150 children received regular medical treatment during observation period.

Exclusion Criteria:
Only children examined at all five cross-sectional examinations considered for this report.
Description of Study Protocol:

Four consecutive annual cross sectional surveys conducted between 1985-1988; five year longitudinal cohort obtained.

All children taught curriculum by teacher throughout five years, mainly focusing on diet and to a lesser degree on physical activity. Curriculum targeted voluntary changes in habitual diet, promoting adoption of “prudent diet,” i.e. reduced consumption of total dietary fat, saturated fat, cholesterol and sodium and increased consumption of complex carbohydrates and fiber and increased ratio of polyunsaturated to saturated fat.

Curriculum paralleled by other health activities, such as blood samplings for cholesterol measurement and periodic screening for blood pressure.

Meetings organized over intervention period to involve parents, including discussions on importance of control of established coronary risk factor rise during childhood; practical recommendations for changes in food preparation and selection given to parents, particularly for families of children in top 25% of BMI distribution at initial survey.

Weekly composition of school snacks recorded by children on an ad hoc diary at beginning of study and five years later; results checked daily by teachers.

Data Collection Summary:


  • weight,
  • height,
  • BMI

(Anthropometric measurements taken in school health office by trained professionals; height and weight measured with standard balance beam and vertical height rod); frequency consumption of different snack foods at school (ad hoc diary).

No blinding indicated.


Nutrition intervention education program.

Control Variables

none specified.

Statistical Analysis

Spearman rank order correlation coefficients used to measure the degree of BMI tracking through time; binary table analysis to calculate positive and negative predictive values of prior BMI measurements to predict BMI groups at age 11-12.


Description of Actual Data Sample:

Original Sample: not specified

Withdrawals/Drop-Outs: not specified

Final Sample: 150 children

Female/male not specified.

Location: Sezze Romano, small town 70 miles south of Rome, Italy.

Race/Ethnicity: not specified.

SES: not specified.

Summary of Results:

Both height and weight significantly increased with age, with resulting BMI highly influenced by growth.

Age-specific Spearman correlation coefficients between 11-12 years, BMI ranks ranged from 0.82 at 6-7 years to 0.88 at 10-11 years (p<.001).

At all ages predictive positive value of prior BMI measurements to predict BMI groups at 11-12 years was found to be significantly high and greater than that predictable by chance alone  (20%).

Negative predictive values varied little (94-96%).

No systematic surveys performed on effectiveness of educational program concerning real modifications of eating habits and behavior.

No positive changes observed in the prevalence of different snack foods consumed at school between beginning and end of five-year dietary intervention.

Author Conclusion:

Strong “tracking phenomenon” for BMI observed at 5 years, suggesting stability over time of lifestyles and dietary habits leading to development of obesity during childhood.

Principal finding is that an intervention program of general nutrition education aimed at improving the level of coronary risk factors in children does not appear to be accompanied by favorable trends in the control of obesity.

Appears that school based, teacher delivered nutrition intervention programs, based on general health and nutrition education towards healthy lifestyles, fail to control overweight and obesity in children (children in this study had high BMI levels during the five years of intervention).

Poor results are likely to be improved by prolonged follow-up study; study has been performed in area where adult obesity is major health problem.

Funding Source:
Government: The Italian National Research Council
Reviewer Comments:


  • no control group;
  • no systematic surveys performed to examine effectiveness of program on real modifications of eating habits and behavior; demographic information limited
  • no results reported for adiposity
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? 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? No
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
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.) No
  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? No
  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%.) No
  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? 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? N/A
  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? 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? 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? N/A
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)? 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? 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