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

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

To assess the effectiveness of health education programs carried out at two different levels of intensity (complete action, including distribution of printed matter, use of audiovisual aids, and presence in schools of qualified staff versus partial action, based exclusively on distribution of printed matter).

Inclusion Criteria:
Pupils in 3-9 year age bracket in three Rome schools which were homogenous as to social and economic conditions and characteristics of the area concerned with data pre- and post-intervention.
Exclusion Criteria:

None specified.

Description of Study Protocol:

Three schools were targets for three different types of action (over one year intervention period):

  • MA school – Multi media action school, 367 pupils, action taken included printed material (pamphlets, memoranda, etc), audiovisuals (short films, slides, etc), discussion meetings with families and teachers
  • WA school – Written action school, 358 pupils, only printed material distributed among pupils, teachers and families
  • C school – Control school, 596 pupils, only BMI was taken at times 0 and 12

Questionnaires completed for each pupil including information on family history of overweight/obesity, personal history of overweight/obesity, birth weight.

Statistical Analysis:

Odds ratio with 95% confidence interval

Data Collection Summary:

Dependent Variables

  • BMI adapted for growing children (central value of normal class derived for each age group from weight to height ratio for 50th percentile and individual classes determined on basis of intervals established based on BMI method for adults)

Independent Variables

  • type of intervention (MA vs WA vs no intervention)

Control Variables

  • sex,
  • age
Description of Actual Data Sample:

Original Sample: children from 3 Rome schools, exact number not given.


Withdrawals/Drop-Outs: children who were not available for measurements at both  at T0 and T12; no specifics given.

Final Sample: 1321 students

Location: Rome, Italy

Race/Ethnicity: Children in Rome, Italy (assume Italian). Specifics not given.

SES: homogenous between the three schools, no specifics given.

Summary of Results:

Distribution of three sets of pupils among five height/weight classes at baseline largely homogenous. Percentage of obese subjects high on average (13.3%, 10.6%, 10.4%); percentages of overweight and underweight similar in WA and C schools (~20%) but diversified in MA school (27.0% overweight, 13.8% underweight).

At end of experiment year:

  • for obese subjects, clear fall (-12.2%) in MA school, moderate increases in WA school and C school (+5.3%, +5.9%)
  • for overweight subjects, clear fall in MA school (-12.1%), largely static in WA and C schools (-2.3%, +0.8%)
  • for normal weight subjects, increase in MA school (+7.2%), decrease in C school (-3.8%)

In obese category, marked fall among females in MA school (+20%), compared to +5.3% in WA school, -2.2% in C school.

Marked fall in 8-9 year age group in MA school (+30.4% for males, +40% for females).

In overweight category, decline for all groups in MA school except males 8-9 years old; notable reduction of –20.8% among females.

In WA and C schools, average increase for male pupils amounting to +12.8% and +4.3% (for females, drop observed).

Obese group showed high degree of stability overall; 70% obese children at time 0 remained in this state after one year of action; differences between schools very slight.

Overweight group showed more mobility: 37.4% in MA school became normal, 23.7% in C school and 29.9% in WA school.

Percentage of obese children with obese or overweight ascendants was more than twice that for normal cases. Birth weight found to have less influence on occurrence of obesity among school children.

Author Conclusion:

Results show validity of dietary education based on multiple forms of action and involving teachers and parents.

MA produced reduction (obesity –12.2%, overweight –12.1%). Simple distribution of printed matter produced very modest results (obesity +5.3%, overweight –2.2%); results similar to those recorded in control school (obesity +5.6%, overweight +0.8%).

WA action, though cheaper and easier, appears unacceptable.

Individuals in obese group were highly static; those in overweight group more mobile. Thus validity is more apparent for purpose of moving children from overweight to normal group while avoiding the inverse process of overweight to obese than for acting on large scale on those in the obese group
Funding Source:
University/Hospital: Istituto di lgiene 'G. sanarelli' Istituto di Terapia Medica Sistematica, Universita 'La Spienza' Roma, Italia
Reviewer Comments:


  • Project was clear--comparison of two types of nutrition education in a school setting.
  • Much needed research that suggests that the more comprehensive education is far more effective than giving just written material

Weaknesses: (This project could be much more powerful, if results were better reported)

  • no demographic information,
  • reporting of data did not show significance--no p values given
  • only odds ratio used for statistical analysis
  • no confidence intervals
  • no specifics on how many children started project and then dropped out.
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? ???
  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? No
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
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? ???
  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? Yes
  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? ???
  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? 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? 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? 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? 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? No
  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? 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