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


Trevino RP, Pugh JA, Hernandez AE, Menchaca VD, Ramirez RR, Mendoza M. Bienestar: a diabetes risk-factor prevention program.  J School Health 1998;68:62-8.

Study Design:
Non-Randomized Controlled Trial
C - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

The primary goals of the Bienestar Health Program are to decrease body fat and/or to decrease dietary fat intake in children. The purpose of the pilot study was program refinement.

Inclusion Criteria:
Not described
Exclusion Criteria:
Not described
Description of Study Protocol:

Pilot program, designed to be culturally and age-appropriate for low-income 4th grade Mexican-American students in 2 parochial schools.

Presented preliminary results: data collected before (Sept) and after (May) 1st of 2-school year intervention (measurements do not appear to be ‘blind’).

Based on Social Cognitive Theory: interventions developed for 4 social systems that should exert the most influence on kids’ health behaviors.

Program components:

  1. Parent health education: nutrition education seminar, cooking classes, theatrical ‘health’ play by children, health newsletters written by children, individual dietetic consultation on child’s diet & therapy recommendations)
  2. School classroom education: nutrition, wellness (self-esteem, weight management, physical activity [PA]), and noncommunicable disease (diabetes, HTN, CVD, CA); includes 28 lessons including teacher’s manual, children’s work-book, tests & keys, transparencies, extensions for thematic instruction & support materials; taught by classroom teachers (training not mentioned)
  3. School cafeteria:  healthy recipes, purchasing foods with high health value, reading food labels, overall guidelines for preparing health meals by food service staff (training not described)
  4. After-school program:  Bienestar Health Club held every 2 weeks (?) to reinforce classroom learning and promotion leisure time moderate to vigorous physical activity in an arts program.

Program aims:

  1.  body fat
  2.  dietary fat
  3.  Fruit and vegetable intake (secondary)
  4.  health knowledge (secondary)
  5.  self-efficacy (secondary)
  6.  self-esteem (secondary)
  7.  PA (secondary)

Statistical Analysis:

Two-tailed paired t-tests utilized to detect mean differences between baseline and post intervention.

Data Collection Summary:

Dependent Variables

  • Body fat (BMI and BIA)
  • Moderate to vigorous PA (questions on frequency of sweating due to exercise)
  • TV viewing (not described)
  • Dietary fat (three 24-hr recalls – 2 week days, 1 weekend day)
  • Fruit and vegetable intake (three 24-hr recalls)
  • Self-efficacy (10-item scale modeled after CATCH tool)
  • Global self-esteem (8-item scale modeled after Rosenberg’s Self-Esteem Scale)
  • Locus of control  (9-item scale modeled after the Desirable and Undesirable Event Locus of Control Scale)
  • Social support (7-item scale modeled after the NHANES Social Support Scale)
  • Family history of diabetes (4 questions to parents on diabetes in self, siblings, mother or father)
  • Protocol fidelity (activity implementation) & participant satisfaction (reaction & level of enthusiasm) – for process evaluation

Independent Variables

  • Bienestar Health Program (see above)
Description of Actual Data Sample:

Baseline Sample: not described

Withdrawals/Drop-Outs:  not described

Final Sample: 102 children, 4th grade (mean = 9.2 y)

Location: San Antonio, TX

Duration:  intervention for 2 school years (1996-98) but results presented for first school year only

Race/Ethnicity:  100% Mexican-American

SES: 2 parochial schools located in poorest school district of city; for 54 households completing survey mean household income = $38,000, 42% of mothers completed no more than high school, 15% single parent households

Summary of Results:

Baseline measures:

  • 50% of 54 households reported family history of diabetes
  • BMI percentile = 60th
  • % body fat = 27.8
  • Fat servings = 7.4
  • Fruit and vegetable servings = 2.5 (what constitutes a serving and if expressed per day not discussed)

Program implementation:

  • All 4th grade students received health curriculum (avg number of lessons not described)
  • After-school Health Club had 45% attendance at >50% of meetings; high attendance group had significantly higher health knowledge score improvement than lower attendance group (data not provided)

Tool evaluation:

  • Results for internal (alpha) estimates for test-retest reliabilities ranged from 0.54 (for self-efficacy) to 0.70 (for self-esteem) [based on convenience sample of 71 4th graders tested 2 weeks apart]

Behavioral outcomes:   

  • dietary fat when measured as servings (7.40 to 5.53 svgs; p<0.01), or as % kcals (30% to 28%, p<0.01), but not when measured in grams (?)
  • Fruit and vegetable (2.5 to 3.1 svgs; p<0.01)
  • 0 change in fiber intake (g)
  • 0 change in cholesterol intake (mg)
  • 0 change in moderate/vigorous PA
  • diabetes health knowledge (44.6 to 62.5 on 100 point scale; p<0.01)
  • self-esteem (26.9 to 27.1 on 40 point scale; p<0.01)
  • self-efficacy differences not analyzed because subscale required revision between measurements

(TV, total energy intake, other measures not reported)

Anthropometric outcomes:

  • 0 change in % body fat (data not provided)
  • BMI analysis not reported

Relationship between behavioral and anthropometric outcomes:

  • Self-esteem analyzed by multiple regression showed a significant inverse relationship with % body fat (data not shown; nor were any other comparisons discussed)
Author Conclusion:

The Bienestar health Program, in a pre-post design, resulted in a significant decrease in dietary fat intake, an increase in fruit and vegetable intake, and an increase in diabetes health knowledge.  These findings suggest that the current model has potential for resulting in the desired outcomes which can reduce diabetes risk factors for the most at-risk population.

Funding Source:
Government: Texas Diabetes Council
University/Hospital: Southwest General Hosptial
Reviewer Comments:


  • Multi-component trial.


  • No control group (necessary at a time in the lifecycle during which BMI and % body fat would normally increase),
  • unclear extent to which school lunch environment was changed (education only?),
  • data on parental/family involvement not provided,
  • no adjustment for potential confounders,
  • inclusion/exclusion criteria, participation/drop-out rate not provided,
  • statistics not well-described.

Other Comments:

Quasi-experimental trial using improved Bienestar Health program & evaluation was being evaluated for the 1997-98 school year with 102 intervention and 82 controls in public schools (not published according to Pubmed)

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? 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 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? 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%.) No
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? ???
  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.) No
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? No
  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? Yes
  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? No
  6.6. Were extra or unplanned treatments described? No
  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)? ???
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? N/A
  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