RESEARCH: 

Just For Kids! was tested in a school-based application in the San Francisco Unified School District. Findings are as follows:

THE EVALUATION OF A SCHOOL-BASED OBESITY PREVENTION PROGRAM AMONG FOURTH GRADE STUDENTS

Desiree V. Rodgers, M.D., M.P.H., Susan R. Johnson, M.D., Jeanne M. Tschann, Ph.D., Elizabeth A. Chesterman, Ph.D., Laurel M. Mellin, M.A., R.D.

Objective: To determine whether a school-based health intervention program (Just For Kids!) could decrease obesity, improve cardiovascular fitness and physical fitness, and increase knowledge regarding the fat content of foods, in fourth grade students.

Design: Quasi-experimental pre-test post-test control group design. Two classrooms received the intervention and two served as the control group.

Participants: All fourth grade students from an urban elementary school.

Intervention: One hour of instruction in the classroom for 10 consecutive weeks. Students completed weekly readings and homework assignments, participated in role plays, practiced problem solving techniques, learned about the fat content of foods, learned to talk about their feelings, and were asked to exercise each day for thirty minutes.

Main Outcome Measures: Outcomes were obesity (body mass index, triceps skinfold thickness), cardiovascular fitness (diastolic blood pressure, systolic blood pressure, and resting heart rate), physical fitness (three minute step test and one minute recovery heart rate) and nutritional knowledge (food questionnaire).

Results: We obtained significant results for the triceps skinfold thickness (F=4.95, p<.03, diastolic blood pressure (F=9.74, p<.01), knowledge (F=5.74, p<.02) and a nearly significant result for systolic blood pressure (F=3.06, p<.08).

Healthy People 2000: National Health Promotion and Disease Prevention Objectives, published in September 1990, contained a national strategy for significantly improving the health of people living in the united States. Reducing overweight to a prevalence of no more that 20% among people aged 20 and older and no more than 15% among adolescents aged 12 through 19, and increasing to at least 30% the proportion of children aged 6 and older engaged regularly in daily, light to moderate, physical activity for thirty minutes were two objectives of this document1. Unfortunately, since Healthy People 2000 was published, there has been a national trend of increasing obesity occurring in minority populations.

Currently, 33% of adults are considered obese. Childhood obesity has increased at least 50% since 1976. Eight percent of obese adolescents are also obese as adults2. Data collected form 1988 to 1994 for the National Health and Nutrition Examinations Surveys III (NHANES III) indicate that the prevalence of overweight among children and adolescents was substantially higher than in the reference population across virtually all racial-ethnic, age and sex groups—3. Previous studies have shown that children are becoming less physically active, are watching more television and are eating high-fat diets, all of which contribute to obesity—4,5,6,7,8.

Obese children are at risk for serious medical problems such as sleep apnea, non-insulin-dependent diabetes mellitus, orthopedic problems, elevated serum cholesterol and hypertension—9. Children can develop cardiovascular risk factors which track into adulthood and lead to cardiovascular disease. Several studies have focused on reducing cardiovascular risk factors in childhood. Although most of these studies had interventions which were effective, they were complex and costly, requiring the involvement of parents, teachers, food service staff, and physical education specialists—10,11,12,13,14,15.

Many studies have used public schools as the place to develop intervention programs to target childhood obesity. School-based obesity intervention programs can be classified as either population-wide or high-risk—16. Population interventions include those programs delivered school-wide to all students, whereas high-risk programs target only those who are overweight—16. In a review article of the major school-based obesity prevention programs, Resnicow concluded that high-risk, and to a lesser degree school-wide interventions can significantly reduce the prevalence of pediatric obesity in the United States—16.

The purpose of this study was to determine whether a relatively low-cost school-based health intervention program (Just For Kids!) modeled after the SHAPEDOWN program could improve children's levels of obesity, cardiovascular fitness, physical fitness, and knowledge regarding the fat content of foods. The program was developed at the University of California, San Francisco in 1979 as part of a Bureau of Maternal and Child Health interdisciplinary adolescent health training program. Just For Kids!emphasizes the importance of good nutrition, physical activity, verbal expression of feelings, and effective communication skills—17,18. We hypothesized that the program would decrease children's levels of obesity, while improving their cardiovascular fitness, physical fitness, and nutritional knowledge.

SUBJECTS AND METHODS:
The Just For Kids! health intervention occurred in a single elementary school located in the San Francisco Unified School District. The study population consisted of all 120 fourth grade students at this urban, predominantly low-income, multi-ethnic elementary school. Informed consent procedures were followed for all students. The study was approved by the Committee on Human Subjects at the University of California, San Francisco.

DESIGN:
The study design was a quasi-experimental pre-test post-test control design. From September 1992 to February 1993, all fourth grade classrooms at the selected school participated in the study. Inclusion criteria for participation in the study were fourth grade elementary students who were enrolled in a regular classroom and were proficient in the English language. Fourth grade children enrolled in special day classes because of learning disabilities, language delays or emotional problems and children enrolled in bilingual classes because of limited English proficiency were not eligible for this study.

Two classrooms received the intervention and two classrooms served as the control group, but they were not randomly assigned to conditions. Several teachers preferred having the intervention taught in their classroom in the Fall, as opposed to the Spring, to prevent any interruption to their lesson plan. Thus, the school principal along with the teachers determined which classrooms would receive the intervention first. The students in the control group received the intervention at the end of the study.

Prior to the start of the intervention, all participating students had health assessments and completed questionnaires. All questionnaires were administered to an entire class at one time. Each questionnaire was read out loud by a trained research assistant. The Principal Investigator of the study or a trained research assistant was available in the classroom to answer children's questions while they completed the questionnaires. All of these children had the same health assessments and completed the same questionnaires again at the end of the intervention period.
The primary study contrast was between students in the intervention and control classroom with respect to changes from baseline (fall 1992) to follow-up (spring 1993). The outcomes were obesity, cardiovascular fitness, physical fitness, and nutritional knowledge.

INTERVENTION COMPONENTS
The two classrooms assigned to the intervention condition received one hour of instruction in the classroom, once a week, for 10 weeks. During the intervention classes, students participated in role plays to learn how to handle teasing, practiced problem solving techniques, and learned more effective ways to talk about their feelings. Using a game-like approach and hands-on materials, children learned the difference between high fat and low fat foods. Children learned about the kinds of physical activities that would make their bodies stronger and healthier. They were given the assignment to exercise for thirty minutes each day, but could not count the physical activity they engaged in at school as part of this assignment.

Students received a workbook titled "Just for Kids" which was adapted from the SHAPEDOWN CHILDREN'S WORKBOOK. The stories and homework were modified to relate to children from single parent homes and multi-ethnic urban environments. Stickers and activity books were used as positive incentives for doing the homework and readings. The students completed weekly readings and homework assignments in this workbook.

OUTCOME MEASURESOBESITY, CARDIOVASCULAR FITNESS,
PHYSICAL FITNESS, AND NUTRITIONAL KNOWLEDGE.

The outcomes were obesity, cardiovascular fitness, physical fitness, and nutritional knowledge. Obesity was measured by the variables body mass index and triceps skinfold thickness. Cardiovascular fitness was measured by diastolic blood pressure, systolic blood pressure, and resting heart rate. Physical fitness was measured by the three minute step test and a one minute recovery heart rate. Nutritional knowledge was measured by a thirty-five item questionnaire.

BODY MASS INDEX
Weight was measured using a Health-O-Meter electronic scale (Model 482). All participants had their weight measured twice. Height was measured using a custom portable stadiometer (Creative Health Products, Plymouth, Mich.). Each child's height was measured twice, while he or she was in socks, with his or her heels together, and toes apart at 45 degree angle. Body mass index, or BMI was calculated as weight in kilograms divided by height in meters squared (kg/m2).

TRICEPS SKINFOLD THICKNESS
The triceps skinfold thickness was measured twice using Holtain calipers (Pfister Import-Export, Inc., Carlstadt, NJ). It was repeated a third time if the first two measurements were discrepant by more than 1.0 mm.

DIASTOLIC AND SYSTOLIC BLOOD PRESSURE
The child's blood pressure was obtained before the child completed fitness testing. The diastolic blood pressure was obtained through a standardized protocol. It is the fourth
Korotkoff (K4) sound for children younger than 12 years of age. Participants were seated with feet resting flat on a surface and right arm resting at heart level. The appropriate cuff was selected from five cuff sizes and placed around the upper arm. Using a standard mercury sphgmomanometer (Baum Desktop Model with V-Lok cuffs), four blood pressures were obtained by rapidly inflating to the maximum inflation level and deflating at a rate of 2mm HG per second, with 30 seconds rest between each determination. The pulse rate was measured for 30 to 60 seconds between blood pressure determinations. All study participants had their systolic blood pressure measured twice.

ONE MINUTE RESTING HEART RATE
Resting heart rate was obtained with the child sitting quietly in a chair for one minute. A stethoscope was placed in the upper sternal area to hear the heart beat. The heart beat was counted for one minute using a stop watch. The child was told to breathe normally during the procedure. The measurement was obtained once.

STEP TEST
Prior to completing the step test, all study participants had their blood pressure and resting heart rate measured and completed fitness testing. The step test was not completed if it was determined that the child had a heart condition, high blood pressure, or a back, knee or hip problem that would be aggravated by this test. The child was asked to step up and down on a 12-inch step. The examiner demonstrated the test to the child (i.e., up right foot, up left foot, down right foot, down left foot). A metronome set to 96 beats per minutes was used to set the pace. If the child was off beat (too slow or too fast), he or she was reminded to speed up or slow down. The test was stopped prematurely if the examiner felt the child changed his or her step after 3 consecutive reminders over a 15 second period. If the child complained of excessive fatigue, dizziness, or other negative physical symptoms, the test was stopped. A stop watch was used to record the minutes and seconds that the child was able to perform the step test (up to 3 minutes maximum).

ONE MINUTE RECOVERY HEART RATE
After the child completed the step-test his or her recovery heart rate was obtained. The child was asked to sit in a chair. The heart rate was located by placing a stethoscope on the upper sternum. The heart rate was counted for a full 1 minute. The measurement was obtained once.

KNOWLEDGE ABOUT THE FAT CONTENTS OF FOODS.
Knowledge was measured by the Types of Food questionnaire, a thirty-five item measure that was developed by Dr. Tom Robinson of Stanford University. Each item on this questionnaire required children to correctly distinguish between a low-fat and a high-fat food. For example, children were asked to determine whether baked chicken or fried chicken had a higher fat content.

SOCIODEMOGRAPHIC VARIABLES.
Demographic information pertaining to the child's ethnicity, gender, birthdate, and age was obtained from the child's pupil data card prior to the start of this study.

STATISTICAL METHODS
Using the Statistical Package for the Social Sciences (SPSS for Windows Release 6.1), we conducted a series of Analysis of Covariance (ANCOVA), one for each outcome measure. In each analysis the pre-test score on a given measure was used as the covariate, intervention versus control was the independent variable, and the post-test score was the dependent variable.


RESULTS:

DEMOGRAPHICS
One hundred and nine students participated in the study. Forty-one percent of the students were African American, 23% were Latino, 21% were Other, 12% were Chinese American, and 3% were White. Fifty percent of the students were male. The students ranged in age from 8.83 to 10.67 years (mean 9.50 years, SD 0.41).

OUTCOME MEASURES
Outcome measures were body mass index, triceps skinfold thickness, diastolic blood pressure, systolic blood pressure, resting heart rate, three minute step-test, one minute recovery heart rate, and knowledge regarding the fat content of foods. We obtained a nearly significant result for the triceps skinfold thickness F (1, 105)=4.95, p<.03 (Table 1). Triceps skinfold thickness increased slightly from the pre-test to the post-test for the control group, but decreased for the intervention group. Thus, the intervention group improved compared to the control group. We also obtained a significant result for diastolic blood pressure F (1, 103)=9.74, p<.01, and a nearly significant result for systolic blood pressure F (1,103)=3.06 p<.08. At pre-test, diastolic blood pressure was similar for both the intervention and control groups. At post-test, it was lower for both groups: however, the intervention group improved more than the control group. At post-test, systolic blood pressure was lower for both groups, but the intervention group improved more than the control group. Finally, we obtained a significant result for nutrition knowledge F(1,84)=5.74, p<.02. The intervention group improved from pre-test to post-test, while the control group scores were almost the same from pre-test to post-test. Thus the intervention group improved more than the control group on triceps skinfold thickness, diastolic pressure, systolic blood pressure, and nutrition knowledge. We did not find significant results for the body mass index, the one minute resting heart rate, the three minute step test, or the one minute recovery heart rate.

COMMENT
Depending on the definition of overweight in children, 10% to 25% of children and adolescents in the United States are overweight—18. A major concern is that obese children tend to become obese adults, facing increased risk for diabetes, cardiovascular disease, and many other chronic diseases—19. Numerous school-based health intervention studies have focused on reducing cardiovascular risk factors in childhood. Frequently, these studies were quite elaborate and were conducted over several years. Our study was impressive in that it was relatively simple and it achieved significant results for several outcomes after a 10-week intervention.

In this study, the intervention group significantly improved on measurements of triceps skinfold thickness, diastolic and systolic blood pressures, and knowledge regarding the fat content of foods. These findings were demonstrated in previous studies—13,14,15.

There are several explanations which may account for the lack of a significant outcome for body mass index. First, the intervention was given over ten consecutive weeks, which was a relatively short length of time. Second the pre-test and post-test weight and height measurements occurred in September and February, spanning a period of time which encompassed several major holidays. Traditionally, major holidays are marked by family gatherings which usually involve the preparation of large amounts of food as part of the celebration. It is not uncommon for people to gain weight during this time. Finally, there is a trend toward earlier pubertal maturation in the United States. Puberty can begin as early as eight years of age, and possibly earlier in some racial groups. Given the multi-ethnic background of the students, and a mean age of 9.5 years, it is possible that some of the students had started puberty prior to the onset of the study. Because early pubertal maturation is associated with higher BMI scores, 20 some students may have been in the process of having a height or weight spurt which would have affected their BMI score.

In this study, we did not obtain a significant result for physical fitness as measured by the three minute step test. This test was probably not the best measure of physical activity to use since the test concluded at the end of three minutes. Therefore, those students who were more physically fit and could have performed this test for a longer period of time were not allowed to continue the fitness testing. Thus, this test did not differentiate between the students who were very physically fit and those who were slightly less fit.

Although this intervention lasted only ten weeks, the results are encouraging. Given our findings, the study should be repeated to further validate the usefulness of the intervention. Ideally, the study would be conducted during an entire school year in several schools to increase the sample size, and classrooms should be randomly assigned to the intervention or the control group. The control group should receive instruction on unrelated topics so that they are similar to the intervention group in all respects for the content of the intervention.

If this study were repeated, and the outcomes were the same, serious consideration should be given to incorporating this intervention into the school curriculum. A low-cost intervention like this could help students develop healthy eating habits and increase their physical activity. These lifestyle changes could significantly impact the incidence of cardiovascular disease in the United States.

Table  1.   Analysis of Covariance for Intervention (I)  versus
Control (C) Groups on Obesity-Related Outcomes


OUTCOME

PRE-TEST
 MEAN  (SD)

POST-TEST
MEAN  (SD)

MEAN
CHANGE

F

Obesity

Body Mass Index

(I)  19.46   (4.44)

19.51   (4.46)

+ 0.05

0.31

(C)  19.04   (3.58)

19.18   (3.57)

+ 0.14

Triceps Skinfold

(I)  14.55   (5.80)

13.73   (5.36)

- 0.82

4.95*

(C)  13.12   (5.80)

13.43   (5.56)

+ 0.31

Carciovascular Fitness

Diastolic Blood Pressure

(I)  62.80   (5.41)

52.36   (12.37)

- 10.43

9.74**

(C)  64.87  (8.98)

59.81   (10.15)

- 5.06

Systolic Blood Pressure

(I)  104.91   (10.48)

98.92   (9.83)

- 5.99

3.06***

(C)  105.42   (9.30)

101.66   (8.07)

- 3.76

Resting Heart Rate

(I) 82.71  (11.17)

87.09   (10.47)

+4.38

0.01

(C)  79.17   (12.80)

86.49   (10.00)

+7.32

Physical Fitness

Step Test

(I) 133.66   (53.33)

147.89   (45.17)

+14.23

1.34

(C) 143.50   (51.68)

143.96   (49.83)

+ 0.46

Recovery Heart Rate

(I)  107.81   (13.25)

105.91   (10.95)

- 1.90

0.04

(C)  102.26   (11.35)

104.73   (13.22)

+ 2.47

Nutritional Knowledge

Food Questionnaire

(I)  0.87   (0.11)

0.91   (0.08)

+ 0.04

5.74

(C)  0.77   (0.17)

0.80   (0.18)

+ 0.03

*** p<.10;  *p<.05;  **p<.01

References
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8. Simons-Morton BG, Batanowski T, Parcel GS, O'Hara NM Matteson RC. Children's frequency of consumption of foods high in fat and sodium. Am J Prev Med. 1990;6(4):218-227.

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13. Vandogen R, Jenner DA, Thompson C, et al. A controlled evaluation of a fitness and nutrition intervention on cardiovascular health in 10 to 12 year old children. Preventive Medicine. 1995;24:9-22.

14. Arbeit ML, Johnson CC, Mott DS, et al. The heart smart cardiovascular school health promotion: behavior correlates of risk factor change. Preventive Medicine. 1992;21:18-32.

15. Harrell JS, McMurray RG, Bangdiwala SI, et al. Effects of a school-based intervention to reduce cardiovascular disease risk factors in elementary-school children: the cardiovascular health in children (CHIC) study. Journal of Pediatrics. 1996;128(6):797-805.

16. Resnicow K. School-based obesity prevention: population versus high-risk interventions. Annals New York Academy of Sciences. 1993; p 154-166.

17. Mellin LM, Managing child and adolescent obesity: the SHAPEDOWN program. Top Clin Nutr. 1991;6($):70-76.

18. Mellin LM, Slinkard LA, Irwin CE. Adolescent obesity intervention: validation of the SHAPEDOWN program. Journal of the Amer Dietetic Assoc. 1987;87:333-338.

19. Hill JO, Trowbridge FL. Childhood obesity: future directions and research priorities. Pediatrics. 1998;101 (suppl):570-574.

20. Power C, Lake JK, Cole TJ. Body mass index and height from childhood to adulthood in the 1958 British birth cohort. Am J Clin Nutr. 1997;66:1094-101.

LINKS:

www.shapedown.com
SHAPEDOWN Pediatric Obesity Program

www.childobesity.com
The Center for Child Obesity