Synthesis of cardiovascular behavioral research for youth health promotion

School-based physical activity programs for promoting physical activity and fitness in children and adolescents aged 6 to 18

BACKGROUND

The World Health Organization (WHO) estimates that 1.9 million deaths worldwide are attributable to physical inactivity and at least 2.6 million deaths are a result of being overweight or obese. In addition, WHO estimates that physical inactivity causes 10% to 16% of cases each of breast cancer, colon, and rectal cancers as well as type 2 diabetes, and 22% of coronary heart disease and the burden of these and other chronic diseases has rapidly increased in recent decades.

OBJECTIVES

The purpose of this systematic review was to summarize the evidence of the effectiveness of school-based interventions in promoting physical activity and fitness in children and adolescents.

SEARCH METHODS

The search strategy included searching several databases to October 2011. In addition, reference lists of included articles and background papers were reviewed for potentially relevant studies, as well as references from relevant Cochrane reviews. Primary authors of included studies were contacted as needed for additional information.

SELECTION CRITERIA

To be included, the intervention had to be relevant to public health practice (focused on health promotion activities), not conducted by physicians, implemented, facilitated, or promoted by staff in local public health units, implemented in a school setting and aimed at increasing physical activity, included all school-attending children, and be implemented for a minimum of 12 weeks. In addition, the review was limited to randomized controlled trials and those that reported on outcomes for children and adolescents (aged 6 to 18 years). Primary outcomes included: rates of moderate to vigorous physical activity during the school day, time engaged in moderate to vigorous physical activity during the school day, and time spent watching television. Secondary outcomes related to physical health status measures including: systolic and diastolic blood pressure, blood cholesterol, body mass index (BMI), maximal oxygen uptake (VO2max), and pulse rate.

DATA COLLECTION AND ANALYSIS

Standardized tools were used by two independent reviewers to assess each study for relevance and for data extraction. In addition, each study was assessed for risk of bias as specified in the Cochrane Handbook for Systematic Reviews of Interventions. Where discrepancies existed, discussion occurred until consensus was reached. The results were summarized narratively due to wide variations in the populations, interventions evaluated, and outcomes measured.

MAIN RESULTS

In the original review, 13,841 records were identified and screened, 302 studies were assessed for eligibility, and 26 studies were included in the review. There was some evidence that school-based physical activity interventions had a positive impact on four of the nine outcome measures. Specifically positive effects were observed for duration of physical activity, television viewing, VO2 max, and blood cholesterol. Generally, school-based interventions had little effect on physical activity rates, systolic and diastolic blood pressure, BMI, and pulse rate. At a minimum, a combination of printed educational materials and changes to the school curriculum that promote physical activity resulted in positive effects.In this update, given the addition of three new inclusion criteria (randomized design, all school-attending children invited to participate, minimum 12-week intervention) 12 of the original 26 studies were excluded. In addition, studies published between July 2007 and October 2011 evaluating the effectiveness of school-based physical interventions were identified and if relevant included. In total an additional 2378 titles were screened of which 285 unique studies were deemed potentially relevant. Of those 30 met all relevance criteria and have been included in this update. This update includes 44 studies and represents complete data for 36,593 study participants. Duration of interventions ranged from 12 weeks to six years.Generally, the majority of studies included in this update, despite being randomized controlled trials, are, at a minimum, at moderate risk of bias. The results therefore must be interpreted with caution. Few changes in outcomes were observed in this update with the exception of blood cholesterol and physical activity rates. For example blood cholesterol was no longer positively impacted upon by school-based physical activity interventions. However, there was some evidence to suggest that school-based physical activity interventions led to an improvement in the proportion of children who engaged in moderate to vigorous physical activity during school hours (odds ratio (OR) 2.74, 95% confidence interval (CI), 2.01 to 3.75). Improvements in physical activity rates were not observed in the original review. Children and adolescents exposed to the intervention also spent more time engaged in moderate to vigorous physical activity (with results across studies ranging from five to 45 min more), spent less time watching television (results range from five to 60 min less per day), and had improved VO2max (results across studies ranged from 1.6 to 3.7 mL/kg per min). However, the overall conclusions of this update do not differ significantly from those reported in the original review.

AUTHORS' CONCLUSIONS

The evidence suggests the ongoing implementation of school-based physical activity interventions at this time, given the positive effects on behavior and one physical health status measure. However, given these studies are at a minimum of moderate risk of bias, and the magnitude of effect is generally small, these results should be interpreted cautiously. Additional research on the long-term impact of these interventions is needed.

School-based physical activity programs for promoting physical activity and fitness in children and adolescents aged 6-18

BACKGROUND

The World Health Organization estimates that 1.9 million deaths worldwide are attributable to physical inactivity. Chronic diseases associated with physical inactivity include cancer, diabetes and coronary heart disease.

OBJECTIVES

The purpose of this systematic review is to summarize the evidence of the effectiveness of school-based interventions in promoting physical activity and fitness in children and adolescents.

SEARCH STRATEGY

The search strategy included searching several databases. In addition, reference lists of included articles and background papers were reviewed for potentially relevant studies, as well as references from relevant Cochrane reviews. Primary authors of included studies were contacted as needed for additional information.

SELECTION CRITERIA

To be included, the intervention had to be relevant to public health practice, implemented, facilitated, or promoted by staff in local public health units, implemented in a school setting and aimed at increasing physical activity, report on outcomes for children and adolescents (aged 6 to 18 years), and use a prospective design with a control group.

DATA COLLECTION AND ANALYSIS

Standardized tools were used by two independent reviewers to rate each study's methodological quality and for data extraction. Where discrepancies existed discussion occurred until consensus was reached. The results were summarized narratively due to wide variations in the populations, interventions evaluated and outcomes measured.

MAIN RESULTS

13,841 titles were identified and screened and 482 articles were retrieved. Multiple publications on the same project were combined and counted as one project, resulting in 395 distinct project accounts (studies). Of the 395 studies 104 were deemed relevant and of those, four were assessed as having strong methodological quality, 22 were of moderate quality and 78 were considered weak. In total 26 studies were included in the review. There is good evidence that school-based physical activity interventions have a positive impact on four of the nine outcome measures. Specifically positive effects were observed for duration of physical activity, television viewing, VO2 max, and blood cholesterol. Generally school-based interventions had no effect on leisure time physical activity rates, systolic and diastolic blood pressure, body mass index, and pulse rate. At a minimum, a combination of printed educational materials and changes to the school curriculum that promote physical activity result in positive effects.

AUTHORS' CONCLUSIONS

Given that there are no harmful effects and that there is some evidence of positive effects on lifestyle behaviours and physical health status measures, ongoing physical activity promotion in schools is recommended at this time.

Pathways curriculum and family interventions to promote healthful eating and physical activity in American Indian schoolchildren

BACKGROUND

Pathways, a multisite school-based study aimed at promoting healthful eating and increasing physical activity, was a randomized field trial including 1704 American Indian third to fifth grade students from 41 schools (21 intervention, 20 controls) in seven American Indian communities.

METHODS

The intervention schools received four integrated components: a classroom curriculum, food service, physical activity, and family modules. The curriculum and family components were based on Social Learning Theory, American Indian concepts, and results from formative research. Process evaluation data were collected from teachers (n=235), students (n=585), and families. Knowledge, Attitudes, and Behavior Questionnaire data were collected from 1150 students including both intervention and controls.

RESULTS

There were significant increases in knowledge and cultural identity in children in intervention compared to control schools with a significant retention of knowledge over the 3 years, based on the results of repeating the third and fourth grade test items in the fifth grade. Family members participated in Family Events and take-home activities, with fewer participating each year.

CONCLUSION

A culturally appropriate school intervention can promote positive changes in knowledge, cultural identity, and self-reported healthful eating and physical activity in American Indian children and environmental change in school food service.

Prevention of type 2 diabetes in young people: a theoretical perspective

Type 2 diabetes in youth is an increasing public health concern, especially in certain minority populations. The current paper consists of four sections. First, we establish the significance of the problem by presenting an overview of epidemiological and physiological evidence. Second, we discuss behavioral issues relevant to the prevention of type 2 diabetes in youth. Third, a qualitative review of existing prevention interventions specific to type 2 diabetes in youth is presented. Results suggest that modest improvements in social cognitive, dietary, and exercise outcomes are possible with diabetes intervention studies, although beneficial changes are difficult to sustain over the long term. Although theoretical frameworks are not always explicit, most studies have utilized elements of the social cognitive theory. Less attention has been paid to sociocultural and community organization variables. Finally, the paper discusses issues of risk definition and intervention sustainability, and presents a comprehensive, theoretically diverse model for the prevention of type 2 diabetes in youth. In summary, we suggest that theories of the natural history and pathophysiology of type 2 diabetes are important to identify modifiable risk factors, while theories of behavioral change are essential to modify the risk factors identified. The combination of sound physiological and behavioral theories should form the basis of prevention intervention design. In addition, an ecologic approach that takes into consideration the dynamic interactions of personal, social, and environmental factors would best promote the long-term adoption of healthful behaviors in a supportive, meaningful, and personally enjoyable context.

Food Perceptions and Dietary Behavior of American-Indian Children, Their Caregivers, and Educators: Formative Assessment Findings from Pathways

Dietary findings from a school-based obesity prevention project (Pathways) are reported for children from six different American-Indian nations. A formative assessment was undertaken with teachers, caregivers, and children from nine schools to design a culturally appropriate intervention, including classroom curriculum, food service, physical education, and family components. This assessment employed a combination of qualitative and quantitative methods (including direct observations, paired-child in-depth interviews, focus groups with child caregivers and teachers, and semistructured interviews with caregivers and foodservice personnel) to query local perceptions and beliefs about foods commonly eaten and risk behaviors associated with childhood obesity at home, at school, and in the community. An abundance of high-fat, high-sugar foods was detected in children's diets described by caregivers, school food-service workers, and the children themselves. Although children and caregivers identified fruits and vegetables as healthy food choices, this knowledge does not appear to influence actual food choices. Frequent high-fat/high-sugar food sales in the schools, high-fat entrees in school meals, the use of food rewards in the classroom, rules about finishing all of one's food, and limited family resources are some of the competing factors that need to be addressed in the Pathways intervention.

Outcomes from a school-based nutrition education program alternating special resource teachers and classroom teachers

This study modified a successful nutrition program to improve its transferability and potential for institutionalization. Specific aims were to determine: 1) if 16 nutrition lessons taught alternately by special resource teachers (SRT) and classroom teachers, could produce outcomes equivalent to 24 SRT lessons; and 2) teachers' reactions to the program. The quasi-experimental design used classrooms (19 treatment and 19 comparison) in matched schools. Surveys and plate waste measured children's outcomes, and classroom teachers were observed and interviewed. Treatment students showed greater knowledge and self-efficacy scores and consumed 0.36 more servings of fruits and vegetables at lunch. Behavioral differences between groups were greater when SRTs provided all instruction. Teachers supported the program and anticipated teaching more nutrition on their own, but noted serious structural barriers. Findings support the need for long-term contact to induce behavior change and the advantage of using teachers specifically trained in nutrition and experiential education.

A public health vs a risk-based intervention to improve cardiovascular health in elementary school children: the Cardiovascular Health in Children Study

OBJECTIVES

This study sought to determine the population effects of both classroom-based and risk-based interventions designed to reduce cardiovascular disease risk factors in children.

METHODS

Elementary school children (n = 2109; age range: 7-12 years) were randomized by school to a classroom-based intervention for all third and fourth graders, a risk-based intervention only for those with 1 or more cardiovascular disease risk factors, or a control group. The 8-week interventions involved both knowledge--attitude and physical activity components.

RESULTS

School-level analyses showed that physical activity in the risk-based group and posttest knowledge in the classroom-based group were significantly higher than in the control group. With regard to trends shown by individual-level analyses, cholesterol dropped more in the classroom-based than in the control group, and skinfold thickness decreased 2.9% in the classroom-based group and 3.2% in the risk-based group (as compared with a 1.1% increase in the control group).

CONCLUSIONS

Both classroom-based and risk-based interventions had positive effects on physical activity and knowledge, with trends toward reduced body fat and cholesterol. However, the classroom-based approach was easier to implement and evidenced stronger results than the risk-based intervention.

Development of a questionnaire to assess knowledge, attitudes, and behaviors in American Indian children

One aim of the Pathways study is to improve the knowledge, attitudes, and behaviors of American Indian children in grades 3-5 regarding physical activity and diet in. This article describes the development of a culturally sensitive, age-appropriate questionnaire to assess these variables. The questionnaire was designed to be administered in the classroom in two 30-min sessions. Questions were developed to assess 4 key areas: physical activity, diet, weight-related attitudes, and cultural identity. Potential questions were written after review of relevant literature and existing questionnaires. Numerous and extensive revisions were made in response to input from structured, semistructured, and informal data collection. Questions were pretested in 32 children in grades 3-5 by using semistructured interviews. Test-retest reliability and the internal consistency of scales were examined in 371 fourth-grade children and subsequently in 145 fourth-grade children. Questions were reviewed by American Indians from the communities involved in the Pathways study several times during the developmental process. The process described here serves as one model for the development of a culturally appropriate tool to assess knowledge, attitudes, and behaviors in American Indian children.

Pathways family intervention for third-grade American Indian children

The goal of the feasibility phase of the Pathways family intervention was to work with families of third-grade American Indian children to reinforce health behaviors being promoted by the curriculum, food service, and physical activity components of this school-based obesity prevention intervention. Family behaviors regarding food choices and physical activity were identified and ranked according to priority by using formative assessment and a literature review of school-based programs that included a family component. The family intervention involved 3 primary strategies designed to create an informed home environment supportive of behavioral change: 1) giving the children "family packs" containing worksheets, interactive assignments, healthful snacks, and low-fat tips and recipes to take home to share with their families; 2) implementing family events at the school to provide a fun atmosphere in which health education concepts could be introduced and reinforced; and 3) forming school-based family advisory councils composed of family members and community volunteers who provided feedback on Pathways strategies, helped negotiate barriers, and explored ideas for continued family participation. For strategy 2, a kick-off Family Fun Night provided a series of learning booths that presented the healthful behaviors taught by Pathways. At an end-of-year Family Celebration, a healthy meal was served, students demonstrated newly learned Pathways activities, and certificates were presented in recognition of completion of the Pathways curriculum. Based on evaluation forms and attendance rosters, strategies 1 and 2 were more easily implemented and better received than strategy 3. Implications for developing family involvement strategies for intervention programs are discussed.

Pathways: a culturally appropriate obesity-prevention program for American Indian schoolchildren

Pathways, a culturally appropriate obesity prevention study for third-, fourth-, and fifth-grade American Indian schoolchildren includes an intervention that promotes increased physical activity and healthful eating behaviors. The Pathways intervention, developed through a collaboration of universities and American Indian nations, schools, and families, focuses on individual, behavioral, and environmental factors and merges constructs from social learning theory with American Indian customs and practices. We describe the Pathways program developed during 3 y of feasibility testing in American Indian schools, with special emphasis on the activities developed for the third grade; review the theoretical and cultural underpinnings of the program; outline the construction process of the intervention; detail the curriculum and physical education components of the intervention; and summarize the formative assessment and the school food service and family components of the intervention.

Evaluation of a health and nutrition education program in primary school children of Crete over a three-year period

BACKGROUND

No national policy for health education in schools exists to date in Greece. The first attempt to apply a school-based health education intervention program was launched in 1992 on all 4,171 pupils registered in the first grade in two counties of Crete. The 1,510 pupils registered in a third county served as controls.

METHODS

The school-based intervention and the seminars organized for parents were primarily aimed at improving children's diet, fitness, and physical activity. Pupils in the first grade in a representative sample of 40 schools were examined prior to the intervention program on a variety of health knowledge, dietary, physical activity, fitness, anthropometric, and biochemical indices. The same measurements were taken after 3 years of the program on 288 intervention group and 183 control group pupils.

RESULTS

Positive serum lipid level changes occurred to a greater extent in the intervention group than the control group. BMI increased less in the intervention group than for controls. The increase in health knowledge and physical activity and fitness levels occurred to a higher extent in the intervention group compared to controls.

CONCLUSIONS

The short-term changes observed in the present study are markedly encouraging and indicate great potential for progressive improvement. Continuation and expansion of such a program may prove to be beneficial in initiating long-term changes.

Effects of physical activity interventions in youth. Review and synthesis

INTRODUCTION

Physical inactivity has been identified as an important public health concern for youth. School and community settings can be important infrastructures for promoting physical activity (PA). This paper reviews studies of physical activity in school and community settings among preschool through college-aged persons to determine characteristics and effects of interventions. Studies in progress are included.

METHODS

Studies from 1980 to 1997 testing physical activity interventions in schools and community settings were identified by computerized search methods and reference lists of published reviews. Studies needed to have used a quantitative assessment of PA, used a comparison or control group, included participants who were preschool through college age, and be conducted in the United States or foreign school or community settings. Significance of effects was examined overall and for various types of interventions.

RESULTS

Twenty-two school-based studies were reviewed, 14 completed and 8 in progress. Three studies were in countries other than the United States. The 8 studies in progress were all in the United States. Only 7 community studies were reviewed, all in the United States. Four studies were in progress. Several community studies involved a high percentage of African-American or Hispanic youth and their families. Studies showing the best results used randomized designs, valid and reliable measurements, and more extensive interventions. Some follow-up results showed PA was sustained after interventions ended.

CONCLUSIONS

The collection of school and community studies is limited for several age groups with none below third grade and only three at college age. There are few community studies. The most is known about upper-elementary-age-students, including the first multicenter randomized trial to report significant results for increasing moderate to vigorous physical activity (MVPA) in physical education (PE) and increase vigorous PA outside of school. A number of older study designs were weak and assessments less than optimal, but studies in progress are stronger. Special attention is needed for girls, middle schools, and community settings for all youth. More objective assessments are needed for measuring PA outside of school and in younger children, since they cannot provide reliable self-report.

Pathways: A school-based program for the primary prevention of obesity in American Indian children

This report describes the proposed intervention and outcome measurement procedures for the Pathways study. Pathways is a multicenter school-based study aimed at reducing the alanning increase in the prevalence of obesity in American Indian children. It is designed as a randomized clinical trial, involving approximately 2,00 third grade children in 40 schools in seven diferent American Indian communities. During a 3-year feasibility phase, which was just completed, the major components of the intervention (school food service, classroom curriculum, physical education program, and family involvement) were developed and pilot-tested. The measurement instruments for body composition; physical activity; dietary intake; and knowledge, attitudes, and behavior were also developed and validated. Comprehensive process evaluation procedures also were defined. As of this writing, thefull-scale intervention program is being initiated and is scheduled to be completed in the spring of 200. The primary aim of the Pathways intervention is to reduce average percent body fat in intervention-school children by at least 3% compared with control-school children by the end of the 3-year intervention. This goal is to be achieved primarily by an increase in physical activity and a reduction in the perceni of dietary fat intake. The program does not seek to reduce dietary energy intake. Rather, it is based on the assumption that a healthier; lower-fat diet, combined with an increase in energy expenditure by increased physical activity, will result in fewer excess calories deposited as body fat.

Psychosocial factors associated with youth involvement in community activities promoting heart health

This study examined factors that influence youth participation in heart disease prevention activities among 2,609 ninth graders in six inner-city public high schools. Constructs derived from social cognitive, empowerment, and community development theories informed the conceptual framework employed. Study participants were diverse with respect to gender, ethnicity, parent education, acculturation, and academic achievement. Perceived incentive value, self-efficacy, outcome expectancies, sense of community, and perceived policy control were all significantly associated with participation in community activities promoting heart health. In multivariate analyses, perceived incentive value, defined as the extent to which participants valued a heart-healthy environment, was most strongly associated with community participation, accounting for 11.9% of the total variance. These findings have implications for designing school curricula and after-school and community programs targeting adolescents' involvement in health advocacy activities.

Implications of the results of community intervention trials

This paper examines the results of population-level interventions conducted in three settings: entire communities, worksites, and schools. Four major conclusions are discussed: (a) Directions for the next generation of community-based interventions include targeting multiple levels of influence; addressing social inequalities in disease risk; involving communities in program planning and implementation; incorporating approaches for "tailoring" interventions; and utilizing rigorous process evaluation. (b) In addition to randomized controlled trials, it is time to use the full range of research phases available, from hypothesis generation and methods development to dissemination research. (c) The public health research agenda may have contributed to observed secular trends by placing behavioral risk factors on the social and media agendas. (d) The magnitude of the results of community intervention trials must be judged according to their potential public health or population-level effects. Small changes at the individual level may result in large benefits at the population level.

Healthy Start: a comprehensive health education program for preschool children

BACKGROUND

Healthy Start is a 3-year demonstration and education research project designed to evaluate the effectiveness of a multidimensional cardiovascular (CV) risk reduction intervention in preschool centers over a 3-year period of time.

METHODS

Two primary interventions are employed. The first is the preschool food service intervention program designed to reduce the total fat in preschool meals and snacks to less than 30% of calories and reduce the saturated fat to less than 10% of calories. The second major intervention is a comprehensive preschool health education curriculum, focused heavily on nutrition.

RESULTS

Effectiveness of the intervention will be determined through evaluation of changes in dietary intake of preschool children at school meals and snacks, especially with respect to intake of total and saturated fat. Evaluation of the education component will include assessment of program implementation by teachers, assessment of changes in nutrition knowledge by preschool children, and assessment of changes in home meals that children consume (total and saturated fat content). Blood cholesterol will be evaluated semiannually to evaluate changes that may be due to modification of dietary intake. Growth and body fatness will also be assessed.

CONCLUSIONS

While substantial efforts have targeted CV risk reduction and health education for elementary school children, similar efforts aimed at preschool children have been lacking. The rationale for beginning CV risk reduction programs for preschool children is based upon the premise that risk factors for heart disease are prevalent by 3 years of age and tend to track over time, most commonly hypercholesterolemia and obesity, both related to nutrition. Since the behavioral antecedents for nutritional risk factors begin to be established very early in life, it is important to develop and evaluate new educational initiatives such as Healthy Start, aimed at the primary prevention of cardiovascular risk factors in preschool children. The purpose of this publication is to describe the rationale and methods for the Healthy Start project.

Heart healthy eating behaviors of children following a school-based intervention: a meta-analysis

The purpose of this meta-analysis was to estimate the effects of school-based interventions on heart healthy eating behaviors of fourth and fifth grade students. The overall effect size (d value) across 12 studies was .24. The 95% confidence interval ranged from .174 to .301. It can be concluded that the school-based cardiovascular health promotion programs had a significant effect on the heart healthy eating behaviors of student participants. Recommendations include identification of reliable measures and inclusion of culturally diverse populations in future studies.

Behavioral research contributions and needs in cancer prevention and control: dietary change

This paper summarizes key behavioral research contributions to the promotion of healthful diets and identifies the outstanding behavioral research needs that could lead to positive dietary changes in the United States. Nutrition plays an important role in the initiation, promotion, and progression of cancer. Dietary guidelines for health promotion and cancer prevention recommend diets that are lower in fat and higher in fiber, fruits, and vegetables. Behavioral research on dietary change has become more rigorous and sophisticated in the past decade, with noteworthy contributions in four areas: behavioral research within clinical trials, self-help or minimal contact intervention strategies, school nutrition programs and services, and advances in the development of measures. Work in progress includes large-scale randomized intervention trials, with the majority of funding for studies to increase fruit and vegetable consumption. There are many needs for further research. Six priority areas for behavioral research are identified and discussed: (1) determinants of dietary behavior and change processes; (2) policy, environmental, and organizational interventions; (3) studies of dietary change and exercise and interventions with persons at high risk for diet-related cancers; (4) methodological research; (5) research on diffusion and dissemination; and (6) systematic behavioral research on dietary change in clinical trials. A concerted research effort in the area of dietary change has great potential benefits for cancer prevention and control and for public health in general.

School-based programs for health-risk reduction

Based on implications from the pediatric studies of cardiovascular risk, it has become imperative that practical methods be developed to begin prevention of heart disease early in life. Schools provide an excellent setting for introducing comprehensive health education and promotion as a public health approach to the general population. A number of school-based health education programs have been developed (Heart Ahead/Heart Smart, CATCH, Gimme 5) for children in kindergarten through high school, in which education and environmental changes have been shown to be effective in promoting healthful behaviors. The effective implementation of health education depends to a large extent on the training and motivation of teachers, administrators, and food service staff. Training Institutes can be important for increasing personal awareness, disseminating information and materials, motivating health education efforts for teachers, food service staff and their students, and evaluating the health risk of school personnel.

Associations between physical activity and other health behaviors in a representative sample of US adolescents

OBJECTIVES

This study examined the associations between physical activity and other health behaviors in a representative sample of US adolescents.

METHODS

In the 1990 Youth Risk Behavior Survey, 11631 high school students provided information on physical activity; diet; substance use; and other negative health behaviors. Logistic regression analyses examined associations between physical activity and other health behaviors in a subset of 2652 high-active and 1641 low-active students.

RESULTS

Low activity was associated with cigarette smoking, marijuana use, lower fruit and vegetable consumption, greater television watching, failure to wear a seat belt, and low perception of academic performance. For consumption of fruit, television watching, and alcohol consumption, significant interactions were found with race/ethnicity or sex, suggesting that sociocultural factors may affect the relationships between physical activity and some health behaviors.

CONCLUSIONS

Low physical activity was associated with several other negative health behaviors in teenagers. Future studies should examine whether interventions for increasing physical activity in youth can be effective in reducing negative health behaviors.

Effects of a school-based intervention to reduce cardiovascular disease risk factors in elementary-school children: the Cardiovascular Health in Children (CHIC) study

OBJECTIVE

To test a classroom-based intervention to reduce cardiovascular disease risk factors in elementary school children.

STUDY DESIGN

This was a randomized, controlled field trial in 12 schools across North Carolina, stratified by geographic region and urban/rural setting. Subjects were 1274 third and fourth graders (48% boys). The intervention, taught by regular classroom and physical education teachers, provided all children an 8-week exercise program and 8 weeks of classes on nutrition and smoking. Data were analyzed at the school level with survey regression models and at the individual level with multivariate analysis of variance and analysis of covariance models; 95% confidence intervals were computed.

RESULTS

Children in the intervention group had significantly greater knowledge (7.9% more correct) and a significant increase in self-reported physical activity than children in the control group. Trends for the intervention group were a reduction in total cholesterol level (-5.27 mg/dl), an increase in aerobic power, a reduction in body fat, and smaller rise in diastolic blood pressure than control children.

CONCLUSIONS

This classroom-based, public health approach improved children's cardiovascular disease risk profiles; it is practical and fairly easy to incorporate into the school day. All children directly receive the potential benefits of the intervention without a risk of labeling. This program can improve health knowledge, habits, and health outcomes of young children at a time when health habits are being formed.

Nutrition and physical activity program to attenuate obesity and promote physical and metabolic fitness in elementary school children

Obesity and low levels of physical and metabolic fitness are risk factors for cardiovascular disease and diabetes. The purpose of this investigation was to attenuate obesity and improve physical and metabolic fitness in elementary school children. Schools have the opportunity, mechanisms, and personnel in place to deliver nutrition education, fitness activities, and a school food service that is nutritious and healthy. Cohorts from grades 3 to 5 in two school districts in rural Nebraska (Intervention/Control) participated in a 2-year study of physical activity and modified school lunch program. Data collection for aerobic capacity, body composition, blood chemistry, nutrition knowledge, energy intake, and physical activity was at the beginning and end of each year. Int received enhanced physical activity, grade specific nutrition education, and a lower fat and sodium school lunch program. Con continued with a regular school lunch and team sports activity program. At year 2, Int lunches had significantly less energy (9%), fat (25%), sodium (21%), and more fiber (17%). However, measures of 24-hour energy intake for Int and Con showed significant differences for sodium only. Physical activity in the classroom was 6% greater for Int compared to Con (p < 0.05) but physical activity outside of school was approximately 16% less for Int compared to Con (p < 0.05). Body weight and body fat were not different between schools for normal weight or obese children. No differences were found for cholesterol, insulin, and glucose; however, HDL cholesterol was significantly greater and cholesterol/HDL was significantly less for Int compared to Con (p < 0.05). It appears that compensation in both energy intake and physical activity outside of school may be responsible for the lack of differences between Int and Con.

Educational and environmental interventions for cardiovascular health promotion in socially disadvantaged primary schools

School-based cardiovascular risk-reduction programs have the potential to influence lifelong habits intrinsic to good health. Following earlier Australian Body owner's Manual (BOM) intervention trials, we examined the effects of two interventions on physiological indicators of risk of cardiovascular disease and on health knowledge: the BOM; and the BOM plus healthy life style programs for teachers and school-canteen interventions (BOM+) over two school years in socially disadvantaged primary schools. Each school was allocated to either a control condition or to one of two intervention conditions. In contrast to the findings of the earlier South Australian trials, there were no statistically-significant changes in aerobic fitness, body fatness or HDL cholesterol; there were significant reductions in diastolic blood pressure, total cholesterol and triglyceride concentration for those in the BOM+ schools. There were significant increases in health and nutrition knowledge for the BOM+ schools, and in health knowledge for the BOM schools.

Statistical design of the Child and Adolescent Trial for Cardiovascular Health (CATCH): implications of cluster randomization

This paper describes some statistical considerations for the Child and Adolescent Trial for Cardiovascular Health (CATCH), a large-scale community health trial sponsored by the National Heart, Lung, and Blood Institute. The trial involves randomization of entire schools rather than individual students to the experimental arms. The paper discussed the implications of this form of randomization for the design and analysis of the trial. The power calculations and analysis plan for the trial are presented in detail. The handling of outmigrating and immigrating students is also discussed.

Measurement of self-efficacy for diet-related behaviors among elementary school children

Health promotion interventions intended to improve dietary behavior frequently incorporate self-efficacy as a construct to enhance behavior change. This paper presents results from a study to establish psychometric properties of a scale to measure children's self-efficacy for selecting healthful food. As part of a series of pilot studies to develop instrumentation for the Child and Adolescent Trial for Cardiovascular Health (CATCH), data were collected on third and fourth grade students (n = 1,127). Data analyses were conducted to estimate internal consistency, test-retest reliability, factorial validity, and criterion related validity. Results revealed acceptable estimates of internal consistency for the dietary self-efficacy scale (coefficient alpha = .84). Self-efficacy was strong associated with the children's usual food choices, accounting for about 34% of variance (Multiple R = .58). Findings support using such an instrument for evaluating intervention programs addressing nutrition behavior and for studies to determine the association of self-efficacy to dietary behavior or related constructs.

Longitudinal tracking of adolescent smoking, physical activity, and food choice behaviors

OBJECTIVES

A major assumption underlying youth health promotion has been that physiological risk factors track from childhood into adulthood. However, few studies have systematically examined how behaviors change during adolescence. This paper describes longitudinal tracking of adolescent health behaviors in two Minnesota Heart Health Program communities.

METHODS

Beginning in sixth grade (1983), seven annual waves of behavioral measurements were taken from both communities (baseline n = 2376). Self-reported data included smoking behavior, physical activity, and food preferences.

RESULTS

A progressive increase in the change to weekly smoking status was observed across the smoking status categories. As students began to experiment with smoking, they were more likely to either begin to be or remain regular smokers. Tracking of physical activity and food choice variables was also apparent. In nearly all the follow-up periods, the students identified at baseline as measuring high remained high, and those measuring low remained low.

CONCLUSIONS

These results indicate that there is evidence of early consolidation and tracking of physical activity, food preference, and smoking behavior. The early consolidation of health behaviors implies that interventions should begin prior to sixth grade, before behavioral patterns are resistant to change. The smoking results suggest that students are experiencing difficulty quitting smoking; thus, youth smoking cessation interventions are warranted.

Dietary sources of fats and cholesterol in US children aged 2 through 5 years

OBJECTIVES

This study of lipid intakes among preschool children (1) analyzed the contributions of 38 food groups to fat, saturated fat, and cholesterol intakes; (2) estimated the effects of food substitutions on intakes; and (3) examined demographic differences in food group intake and food group sources of these lipids.

METHODS

The sample consisted of 547 children, aged 2 to 5 years, from the US Department of Agriculture's 1985 and 1986 Continuing Surveys of Food Intakes by Individuals. Dietary information for 4 nonconsecutive days throughout a year was used. All foods were classified into groups and the lipids contributed from each group were computed.

RESULTS

Over 80% of the children consumed more total fat, saturated fats, and cholesterol than is recommended. The major source of total fat and saturated fats was whole milk; the major sources of dietary cholesterol were eggs and whole milk. Children's food consumption patterns differed by region of the country and race/ethnicity, providing opportunities to refine nutrition education interventions and evaluations.

CONCLUSIONS

By substituting lower-fat foods for the major sources of saturated fats, significant reductions in preschool children's intakes of saturated fats, fat, and dietary cholesterol could be achieved.

CATCH: classroom process evaluation in a multicenter trial

The purpose of this paper is to describe the process evaluation model for the classroom curricula of the Child and Adolescent Trial for Cardiovascular Health (CATCH) Project. The process evaluation plan specifically targets how much each curriculum was implemented, to what degree it was implemented as designed, and the barriers to implementation. Additionally, the rationale for each of the process evaluation measures and the instrument development process are presented. Data resulting from these measures will be essential in order to answer questions regarding the internal validity of the main outcomes of the project. Specific examples and sample results are provided from the CATCH third-grade classroom curriculum, which was implemented the first year of CATCH. A discussion also is presented of how the findings from a sample of these measures were used to gain additional insight on the salient features of the curriculum, and how those features may be related to student outcomes.

Design of process evaluation within the Child and Adolescent Trial for Cardiovascular Health (CATCH)

Process evaluation complements outcome evaluation by providing data to describe how a program was implemented, how well the activities delivered fit the original design, to whom services were delivered, the extent to which the target population was reached, and factors external to the program that may compete with the program effects. The process evaluation system used in the Child and Adolescent Trial for Cardiovascular Health (CATCH) is presented in this paper. The conceptual model underlying the CATCH process evaluation system is described, and process measures and data collection protocols are reviewed. Functions of process evaluation data in the trial include: (1) describing the implementation of the program, (2) quality control and monitoring, and (3) explaining program effects. The importance of incorporating process evaluation into final outcome analyses and assessments of program impact is emphasized.

CATCH: process evaluation of environmental factors and programs

The Child and Adolescent Trial for Cardiovascular Health (CATCH) is a multicenter trial designed to test the effectiveness of school and family-based cardiovascular health promotion for preadolescents. CATCH interventions target multiple cardiovascular health behaviors such as dietary intake of fat and sodium, physical activity, and tobacco use. Evaluation includes physiological, psychosocial, behavioral, and process measures. An important aspect of the process evaluation is the assessment of environmental factors and "secular events" in both intervention and control schools that may affect outcomes independently of the CATCH interventions. With such information, CATCH investigators are able to isolate the impact of the CATCH intervention from competing (non-CATCH) factors as well as "track" proximal (i.e., immediate and short term) changes related to the intervention that may in turn lead to "distal" (long-term) behavior change. The School Health Questionnaire, the major process evaluation tool for monitoring secular and environmental changes in the schools, is described in detail, and data describing tobacco-related environmental factors and secular events are presented.

Cohort versus cross-sectional design in large field trials: precision, sample size, and a unifying model

In planning large longitudinal field trials, one is often faced with a choice between a cohort design and a cross-sectional design, with attendant issues of precision, sample size, and bias. To provide a practical method for assessing these trade-offs quantitatively, we present a unifying statistical model that embraces both designs as special cases. The model takes account of continuous and discrete endpoints, site differences, and random cluster and subject effects of both a time-invariant and a time-varying nature. We provide a comprehensive design equation, relating sample size to precision for cohort and cross-sectional designs, and show that the follow-up cost and selection bias attending a cohort design may outweigh any theoretical advantage in precision. We provide formulae for the minimum number of clusters and subjects. We relate this model to the recently published prevalence model for COMMIT, a multi-site trial of smoking cessation programmes. Finally, we tabulate parameter estimates for some physiological endpoints from recent community-based heart-disease prevention trials, work an example, and discuss the need for compiling such estimates as a basis for informed design of future field trials.

Community-wide youth exercise promotion: long-term outcomes of the Minnesota Heart Health Program and the Class of 1989 Study

The Class of 1989 Study, part of the Minnesota Heart Health Program (MHHP), involved a population-wide research and demonstration project to reduce cardiovascular disease in three intervention communities in the North-Central United States (1980-1993). Beginning in sixth grade (1983), seven annual waves of measurements were taken from students in one of the MHHP intervention communities and its matched pair (baseline N = 2,376). Self-reported data were collected at each time period describing a variety of health-related behavior, including hours of exercise engaged in per week and duration and intensity of regular physical activity. Using school as the unit of analysis, physical activity levels throughout most of the follow-up period were significantly higher in the intervention community for females. Males' average values were higher in the intervention community, but were largely statistically insignificant. Results suggest multiple intervention components such as behavioral education in schools and complementary community-wide strategies can produce lasting improvement in adolescent physical activity, particularly with female students.

Cardiovascular risk stability: from grade school to high school

School-based, cardiovascular risk reduction programs have increased dramatically over the past decade. Though a wide range of evaluation plans have been implemented, limited longitudinal data are available to estimate the effectiveness of these risk reduction programs. The purposes of this study were to describe the stability of risk factors, the changes in cardiovascular risk from grade school to high school, and the differences in risk between gender. The sample (N = 195) of high school students was developed from three cohorts of elementary school students who participated in a risk reduction program in the sixth grade. Three to six years had elapsed since the students participated in the risk reduction program, thus providing a longitudinal view of participants' risk. Subject risk for obesity and high cholesterol level was stable although significant changes were noted for heart rate recovery and blood pressure. The only gender difference in risk was for elevated cholesterol level among female students. Nursing implications are presented.

Multiple influences on the acquisition and socialization of children's health attitudes and behavior: an integrative review

An overview and synthesis of the literature documenting various influences on the socialization and acquisition of children's health attitudes and behavior is the focus of this review. Cognitive-developmental approaches to understanding children's health attitudes are presented, followed by an exploration of an individual differences perspective on children's acquisition of health attitudes and behavior. The influence of various socialization agents, including families, peers, schools, and the media, on children's acquisition of health attitudes and behavior is considered. Implications of these findings for social policy, future research, and modeling of child health attitudes and behavior are examined.

Health perceptions and behaviors of school-age boys and girls

This study described and compared the health perceptions and behaviors of 83 school-age boys and girls. An age-appropriate interview schedule was designed to collect data related to demographic characteristics, health perceptions, safety, life-style practices, nutrition, dental health, and care of minor injuries. Findings indicated that most boys and girls viewed themselves as healthy and managed their own care fairly well in the areas of seat belt use, exercise, and dental health. Nutrition was identified as an area of concern, with 10% of the children skipping breakfast, and over half eating snacks with empty calories. Generally, children were found to be knowledgeable in the management of simple injuries and how to respond in the event of an emergency. Boys and girls were similar in all areas of health perceptions and behaviors except for dental health, with boys reporting more regular visits to the dentist than did girls. Further research is needed to learn more about the process by which school-age children acquire positive health behaviors to assist nurses to design and implement intervention programs that appropriately address the needs of this age group.

[Design of and involvement in an interventional study on health education in basic schools: the Pforzheim Study]

We report the design and the determinants of participation in a controlled, randomized trial evaluating the efficiency of a school-based health education and promotion program. The health education program "Gesund leben macht Spass" ("Healthy living is fun") was developed by the AOK Pforzheim, a statutory health insurance organization in South West Germany. In this 7 week program, the body structure is presented systematically, and the children themselves are asked to correlate structure with function. During the fall of 1988, 490 pupils in 22 third grade level classes at 11 primary schools in Pforzheim and vicinity were invited to participate in a health survey (378 consenting parents = 77.1%). Ten schools with 19 classes and 413 students were admitted to the study (333 participating students = 80.6%). One year later, 290 children (70.2%) were available for follow up. Both examinations covered body weight and height, blood pressure level, total cholesterol, and the assessment of health related knowledge, attitudes and behavior by a repeat questionnaire. Parental consent rates in participating schools varied between 66.7% and 100%. Initial student participation was distinctly higher in schools in a rural (85.2%) as compared to an urban environment (73.2%), and among children of German nationals (83.2%) as compared to children of other nationalities (70.9%). After one year, participation rates in these groups approached each other. Schools in the intervention and control groups were similar in sociodemographic characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)