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Citation:

Luepker RV, Perry CL, McKinlay SM, Nader PR, Parcel GS, Stone EJ, Webber LS, Elder JP, Feldman HA, Johnson CC, et al. Outcomes of a field trial to improve children's dietary patterns and physical activity. The Child and Adolescent Trial for Cardiovascular Health. CATCH collaborative group. JAMA. 1996 Mar 13; 275(10): 768-776.  


PubMed ID: 8598593
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 assess the effectiveness of a health behavior intervention (school lunch menu changes, physical activity program in physical education class, classroom education and family activities) in elementary school children. 

Inclusion Criteria:
  • Proximity of elementary school to study center (California, Louisiana, Minnesota, Texas)
  • Diverse ethnic groups enrolled at school
  • Food service's potential for intervention
  • Commitment to offer 90 minutes of physical education each week
  • Willingness to participate in a three-year study.
Exclusion Criteria:

None specified.

Description of Study Protocol:

Design

  • Schools were randomized to treatment (56 schools) or control (40 schools) groups after baseline measurements were taken. The treatment schools were divided into two groups, 28 schools each:
    • Food service modifications, physical activity program, CATCH curricula
    • Food service modifications, physical activity program, CATCH curricula, family-based program
    • Control groups received "the usual health curricula, PD and food service programs, but none of the CATCH interventions" 
  • Measurements were made at baseline (Fall 1991) and at follow-up (Spring 1994). Students who left the district, but resided within a 100-mile radius underwent measurements for intention-to-treat analysis.

Dietary Intake/Dietary Assessment Methodology

  • Efficacy of the Eat Smart program was determined by collecting recipes, menu of meals offered and vendor product information on five consecutive days. Recipe and menu analysis was conducted with Nutrition Data System of the University of Minnesota Nutrition Coding Center.
  • Student diets were assessed by a non-quantified food record and a 24-hour dietary recall in a sub-sample of 30 students per school. Data were entered into the Nutrition Coding Center database for evaluation.

Intervention

The CATCH intervention was comprised of multiple parts:

  • Eat Smart: Food service intervention, with the goal to provide lunch meals that were lower in fat (less than 30% kcal as total fat, less than 10% kcal as saturated fat, 600 to 1,000mg sodium per serving). The intervention consisted of a one-day training session at the begining of each school year.
  • Physical education (PE) intervention: The goal was to increase moderate to vigorous physical activity to 40% of PD class time. The intervention consisted of one to 1.5 days of training for PE specialists each year.
  • Classroom curricula: Targeted psycho-social factors and skills focused on eating behaviors and physical activity patterns. Teachers attended one- to 1.5-day training sessions each year to learn how to implement the curricula.
  • Family-based program: Activity packets that required adult participation and family fun night.

Statistical Analysis

  • Individual level measures were analyzed via ANCOVA. Follow-up variable was the dependent variable, intervention group was the independent variable and baseline value was the covariate. ANCOVA was controlled for sex, race, field site and the random effect of school within the site. Individual-level measures included physiological measures, 24-hour food recall and a nine-minute run.
  • School-level measures were analyzed via repeated measures ANCOVA with Catch intervention group as the independent variable. School-level measures included school menu data, Health Behaviors Questionnaire and PE class observations.
  • Each end point was also tested for interactions of the CATCH intervention group with the site
  • SAS statistical software was used with mixed-model procedure. P-values were not adjusted for multiple comparisons.
Data Collection Summary:

Timing of Measurements

  • Fall 1991 (baseline) and Spring 1994 (follow-up) were major measurement times
  • Other data was collected on a semester basis.

Dependent Variables

  • Nutrient content of school lunches (recipe and menu analysis with Nutrition Data System)
  • Amount of time spent doing moderate to vigorous physical activity in PE class (System for Observing Fitness Instruction Time, observation done by trained observer)
  • Health Behavior Questionnaire (assessing dietary knowledge, intentions, usual food choices, social reinforcement and support and self-efficacy)
  • 24-hour dietary recall (Nutrition Coding Center database, assessed in 30 students per school)
  • Self-administered Physical Activity Checklist (assessed type, duration and intensity of leisure time physical activities, television watching and video games)
  • Non-fasting blood samples for total cholesterol, HDL-cholesterol and apolipoprotein B (in 45% randomly selected sample)
  • Systolic and diastolic blood pressure and pulse (automated blood pressure cuff)
  • Height (standiometer)
  • Weight (balance scale)
  • Body mass index (BMI) (calculated from height and weight)
  • Skinfold thickness: Tricep, subscapular (Lang calipers)
  • Aerobic fitness (timed nine-minute run).

Independent Variables

CATCH intervention group or control.

Control Variables

For Individual-level analysis:

  • Sex
  • Race
  • Field site
  • Random effect of school within the site.
Description of Actual Data Sample:
  • Initial N: N=5,106: (2,645 boys, 2,461 girls)
  • Attrition (final N): N=4,019
  • Age: Third grade (baseline) to fifth grade (follow-up) students
  • Ethnicity (at baseline): White (3,530), African American (674), Hispanic (708), Other (194)
  • Other relevant demographics:
    • All 96 schools maintained participation in the program for the three-year study period
    • 60.4% of students enrolled in third grade were measured at baseline
  • Anthropometrics:
    • There were no differences in site, sex or ethnic group among those who did and did not participate 
    • There were no significant (NS) differences at baseline for any of the end points between the participants and those lost to follow-up 
    • There were no differences in follow-up participation by intervention assignment or sex 
    • African American students in California were more likely to drop out 
  • Location: California, Louisiana, Minnesota, Texas.
Summary of Results:

Training sessions were attended by 80% to 94% of the teachers, specialists and staff at the schools. 90% of the curricula activities were completed, 70% of families participated in the home activities and 67% families attended family fun night.

School Lunch Energy and Percentage Fat Content

Variables

Baseline

Mean (SE)

Follow-up

Mean (SE)

Statistical Significance at Follow-up (Control vs. Intervention)

Energy content of school lunch (mJ)

Control 2.97 (0.04)

Interv.* 3.01 (0.04)

Control 3.12 (0.04)

Interv. 2.86 (0.04)

P<0.001

Energy from total fat-school lunch (percentage)

Control 38.9 (0.5)

Interv. 38.7 (0.04)

Control 36.2 (0.5)

Interv. 31.9 (0.4)

P<0.001

Energy from saturated fat, school lunch (percentage)

Control 15.1 (0.3)

Interv. 14.8 (0.2)

Control 13.7 (0.3)

Interv. 12.0 (0.2)

 P=0.007

*Interv. = Intervention school

24-hour Diet Recall

Variable Control (Change from Baseline) Mean (SEM) Intervention (Change from Baseline) Mean (SEM) Statistical Significance Between Control and Intervention
Total energy intake (mJ) 0.60 (0.15) 0.14 (0.12) 0.01
Percentage total fat -0.5 (0.4) -2.3 (0.3) 0.001
Percentage saturated fat -0.4 (0.2) -1.1 (0.1) 0.005
Percentage polyunsaturated fat 0.3 (0.1) -0.1 (0.1) 0.01
Percentage monounsaturated fat -0.3 (0.2) -0.8 (0.1) 0.02

Other Findings

  • Cholesterol content did not differ between control and intervention schools at follow-up. Potassium content was significantly greater in the intervention schools than the control schools at follow-up.
  • Average physical education lesson lasted 28.4 to 30.1 minutes and did not differ during the study period. Energy expenditure (kJ per kg) increased significantly at semesters two, four and five in the intervention group compared to the control group, but not at semesters three and six. Energy expenditure per hour increased significantly at semesters two, three and four in the intervention group compared to the control group, but no differences were observed in semesters five and six.  Intervention schools spent more time doing vigorous and moderate-to-vigorous activity than the control schools.
  • As assessed by the health behaviors questionnaire, dietary knowledge was significantly greater in the intervention schools than the control schools. The addition of family activities to the school-based program improved dietary knowledge in semester four, but not semester two or six. Scores for dietary intention and usual food choice were significantly higher in the intervention schools than the control schools.
  • Change from baseline in physiological measures did not differ between control and intervention school in any measures.
Author Conclusion:
  • The CATCH intervention successfully modified nutrient and energy content of school lunch menus and increased the amount of moderate-to-vigorous physical activity in PE class
  • Serum cholesterol did not change significantly
  • The CATCH intervention improved psycho-social factors, decreased self-reported fat intake and increased self-reported physical activity
  • Changes in the eating patterns did not impair growth
  • Lack of difference in serum cholesterol can be attributed to the modest changes in dietary intake, although dietary intake was significantly different between control and intervention schools
  • These dietary modifications may have a greater impact as the child reaches adulthood, rather than during childhood itself
  • This intervention demonstrates that eating behaviors can be changed without substantial resource or time commitments. This is a feasible and effective model for American schools.
Reviewer Comments:
  • This is a large intervention trial that targeted a specific group of individuals (third to fifth graders)
  • The authors described the limitations of the study
    • Statistical power (powered to detect changes in serum cholesterol)
    • Participation rates (60%)
    • Amount of intervention (had to be feasible for public schools)
    • Lack of community participation (grocery stores, mass media, parks)
  • Interventions were not completely described, but citations were included for further resources
  • Outcomes were assessed in a logical, thorough manner
  • Given the sample population and the types of intervention, results from this study are applicable to many different communities in the US. 

 


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?
No
  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?
N/A
  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.)
???
  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?
N/A
  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