Warm climates of the past--a lesson for the future?

This Discussion Meeting Issue of the Philosophical Transactions A had its genesis in a Discussion Meeting of the Royal Society which took place on 10-11 October 2011. The Discussion Meeting, entitled 'Warm climates of the past: a lesson for the future?', brought together 16 eminent international speakers from the field of palaeoclimate, and was attended by over 280 scientists and members of the public. Many of the speakers have contributed to the papers compiled in this Discussion Meeting Issue. The papers summarize the talks at the meeting, and present further or related work. This Discussion Meeting Issue asks to what extent information gleaned from the study of past climates can aid our understanding of future climate change. Climate change is currently an issue at the forefront of environmental science, and also has important sociological and political implications. Most future predictions are carried out by complex numerical models; however, these models cannot be rigorously tested for scenarios outside of the modern, without making use of past climate data. Furthermore, past climate data can inform our understanding of how the Earth system operates, and can provide important contextual information related to environmental change. All past time periods can be useful in this context; here, we focus on past climates that were warmer than the modern climate, as these are likely to be the most similar to the future. This introductory paper is not meant as a comprehensive overview of all work in this field. Instead, it gives an introduction to the important issues therein, using the papers in this Discussion Meeting Issue, and other works from all the Discussion Meeting speakers, as exemplars of the various ways in which past climates can inform projections of future climate. Furthermore, we present new work that uses a palaeo constraint to quantitatively inform projections of future equilibrium ice sheet change.

Effects of the CATCH physical education intervention: teacher type and lesson location.

BACKGROUND: Substantial differences exist in how and where physical education (PE) is conducted in elementary schools throughout the United States. Few effectiveness studies of large-scale interventions to improve PE have been reported. DESIGN: Multicenter randomized trial. SETTING/ PARTICIPANTS: The Child and Adolescent Trial for Cardiovascular Health (CATCH) was implemented in PE classes in 96 schools (56 intervention, 40 control) in four study centers: California, Louisiana, Minnesota, and Texas. INTERVENTION: The 2.5-year PE intervention consisted of professional development sessions, curricula, and follow-up consultations. MAIN OUTCOME MEASURES: Intervention effects on student physical activity and lesson context in PE were examined by teacher type (PE specialists and classroom teachers) and lesson location (indoors and outdoors). RESULTS: Differential effects by teacher type and lesson location were evidenced for both physical activity and lesson context. Observations of 2016 lessons showed that intervention schools provided more moderate-to-vigorous physical activity (p=0.002) and vigorous physical activity (p=0.02) than controls. Classroom teachers improved physical activity relatively more than PE specialists, but PE specialists still provided longer lessons and more physical activity. Classroom teachers increased lesson length (p=0.02) and time for physical fitness (p=0.03). CONCLUSIONS: The intervention improved PE of both specialists' and classroom teachers' lessons. States and districts should ensure that the most qualified staff teaches PE. Interventions need to be tailored to meet local needs and conditions, including teacher type and location of lessons.

Translation of nutritional sciences into medical education: the Nutrition Academic Award Program.

For the past 40 y the scientific community has decried the inadequacy of the training of physicians and other health professionals in the subject of human nutrition. In 1997 the National Heart, Lung, and Blood Institute developed the Nutrition Academic Award (NAA) Program, an initiative to improve nutrition training across a network of US medical schools. The purpose of this funding, which began in 1998, is to support the development and enhancement of nutrition curricula for medical students, residents, and practicing physicians to learn principles and practice skills in nutrition. The NAA recipients developed the Nutrition Curricular Guide for Training Physicians, a plan to incorporate clinical guidelines into physician practice skills, create educational and assessment practice tools, and evaluate curricula, materials, and teaching tools. Dissemination of NAA activities and materials will be facilitated by a national website, presentations and publications, and consultants and advisors from the NAA nutrition education programs. The NAA Program constitutes a major new effort to enhance nutrition knowledge and skills among health care providers and to effectively apply the science of human nutrition to clinical medicine. This article describes the purpose and aims of the NAA Program, the organizational structure of the network of recipients, a profile of the recipients and individual programs at 21 medical schools, the various strategies to overcome barriers in training physicians in human nutrition, and collaborative and dissemination efforts.

Reliability and validity of the Child and Adolescent Trial for Cardiovascular Health (CATCH) Food Checklist: a self-report instrument to measure fat and sodium intake by middle school students.

OBJECTIVE: To develop a scoring algorithm and evaluate the reliability and validity of scores from the Child and Adolescent Trial for Cardiovascular Health (CATCH) Food Checklist (CFC) as measures of total fat, saturated fat, and sodium intake in middle school students. DESIGN: Randomized, controlled trial in which participants were assigned to 1 of 3 study protocols that varied the order of CFC and 24-hour dietary recall administration. Criterion outcomes were percent energy from total fat, percent energy from saturated fat, and sodium intake in milligrams. SUBJECTS/SETTING: A multiethnic sample (33% ethnic and racial minorities) of 365 seventh-grade students from 8 schools in 4 states. STATISTICAL ANALYSES: Multivariable regression models were used to calibrate the effects of individual food checklist items; bootstrap estimates were used for cross-validation; and kappa statistics, Pearson correlations, t tests, and effect sizes were employed to assess reliability and validity. RESULTS: The median same-day test-retest reliability kappa for the 40 individual CFC food items was 0.85. With respect to item validity, the median kappa statistic comparing student choices to those identified by staff dietitians was 0.54. Test-retest reliability coefficients ranged from 0.84 to 0.89 for CFC total nutrient scores. Correlations between CFC scores and 24-hour recall values were 0.36 for total fat, 0.36 for saturated fat, and 0.34 for sodium; CFC scores were consistent with hypothesized gender differences in nutrient intake. APPLICATIONS/CONCLUSIONS: The CFC is a reliable and valid tool for measuring fat, saturated fat, and sodium intake in middle school students. Its brevity and ease of administration make the CFC a cost-effective way to measure middle school students' previous day's intake of selected nutrients in school surveys and intervention studies.

Prevalence of marked overweight and obesity in a multiethnic pediatric population: findings from the Child and Adolescent Trial for Cardiovascular Health (CATCH) study.

OBJECTIVE: Determine the prevalence of marked overweight and obesity among children in the Child and Adolescent Trial for Cardiovascular Health (CATCH), identify high risk groups, and compare findings to other recent studies. DESIGN: Cohort study. SUBJECTS/SETTING: Five thousand one hundred-six school children who were participants in CATCH at baseline (age approximately 9 years) during 1991 and 4,019 of those children who had follow-up data from 1994 (age approximately 1 years) available. METHODS: Body mass index (BMI), triceps and subscapular skinfolds, subscapular to triceps skinfold (S/T) ratio, and an estimate of body fat distribution from skinfolds was calculated. Findings were compared to population-based reference data from the First National Health and Nutrition Examination Survey, 1971 to 1973 (NHANES I), to data from the Bogalusa Heart Study, and to data from the Third National Health and Nutrition Examination Survey, 1988 to 1994 (NHANES III). RESULTS: Children in CATCH were markedly heavier and fatter than the NHANES I population and more comparable to the NHANES III population, especially those in the upper percentiles. The prevalence of obesity based on BMI and triceps skinfolds >95th percentile among CATCH children was higher in boys than in girls at both baseline (boys 9.1%, girls 8.6%) and follow-up (boys 11.7%, girls 7.2%). It was higher among African-Americans and Hispanics than whites for both sexes. S/T ratios did not differ appreciably from those observed in the NHANES I reference population, suggesting that body fat distribution was more stable over time than BMI and skinfolds. APPLICATIONS: Our findings support other recent reports that American children, especially African-American and Hispanic children, are becoming heavier and fatter. Preventive measures are warranted, especially for high-risk youth.

Physical activity behavior change: issues in adoption and maintenance.

The many benefits of participation in regular moderate- or vigorous-intensity physical activity are well established, yet more than 60% of the population is sedentary or insufficiently active. Published studies have revealed that behavior modification and cognitive-behavior modification can be successfully used to assist patients, healthy adults, and youth in the adoption of physically active lifestyles. However, few studies with adults and youth have examined the maintenance of physical activity behavior beyond 6 months of adoption of this behavior. Maintenance of physical activity is critically important because ongoing participation in the behavior is necessary to sustain health benefits. Knowledge of effective intervention strategies for long-term maintenance of physical activity is at an early stage. The authors provide a summary of what is known about the maintenance of physical activity behavior in adults and youth and how physical activity behavior relates to other health behaviors such as smoking, as well as recommendations for research on physical activity behavior change and maintenance.

REACT theory-based intervention to reduce treatment-seeking delay for acute myocardial infarction. Rapid Early Action for Coronary Treatment.

Coronary heart disease (CHD) remains the leading cause of mortality in the U.S. Innovations in reperfusion therapies can potentially reduce CHD morbidity and mortality associated with acute myocardial infarction (AMI) when treatment is initiated within the first few hours of symptom onset. However, delay in seeking treatment for AMI is unacceptably lengthy, resulting in most patients being ineligible for reperfusion therapies. The Rapid Early Action for Coronary Treatment (REACT) Trial is a four-year, 20-community, randomized trial to design and test the effectiveness of a multi-component intervention to reduce patient delay for hospital care-seeking for AMI symptoms. This manuscript describes the development and content of the theoretically-based REACT intervention and summarizes: (1) the research literature used to inform the intervention; (2) the behavioral theories used to guide the development, implementation, and evaluation of the intervention; (3) the formative research undertaken to understand better decision-making processes as well as barriers and facilitators to seeking medical care as perceived by AMI patients, their families, and medical professionals; (4) the intervention design issues that were addressed; (5) the synthesis of data sources in developing the core message content; (6) the conceptualization for determining the intervention target audiences and associated intervention components and strategies, their integration with guiding theoretical approaches and implementation theories for the study, and a description of major intervention materials developed to implement the intervention; and (7) the focus of the outcome, impact, and process measurement based on the intervention components and theories on which they were developed.

Three-year maintenance of improved diet and physical activity: the CATCH cohort. Child and Adolescent Trial for Cardiovascular Health.

OBJECTIVE: To assess differences through grade 8 in diet, physical activity, and related health indicators of students who participated in the Child and Adolescent Trial for Cardiovascular Health (CATCH) school and family intervention from grades 3 through 5. DESIGN: Follow-up of the 4-center, randomized, controlled field trial with 56 intervention and 40 control elementary schools. PARTICIPANTS: We studied 3714 (73%) of the initial CATCH cohort of 5106 students from ethnically diverse backgrounds in California, Louisiana, Minnesota, and Texas at grades 6, 7, and 8. RESULTS: Self-reported daily energy intake from fat at baseline was virtually identical in the control (32.7%) and intervention (32.6%) groups. At grade 5, the intake for controls remained at 32.2%, while the intake for the intervention group declined to 30.3% (P<.001). At grade 8, the between-group differential was maintained (31.6% vs 30.6%, P = .01). Intervention students maintained significantly higher self-reported daily vigorous activity than control students (P = .001), although the difference declined from 13.6 minutes in grade 5 to 11.2, 10.8, and 8.8 minutes in grades 6, 7, and 8, respectively. Significant differences in favor of the intervention students also persisted at grade 8 for dietary knowledge and dietary intentions, but not for social support for physical activity. No impact on smoking behavior or stages of contemplating smoking was detected at grade 8. No significant differences were noted among physiologic indicators of body mass index, blood pressure, or serum lipid and cholesterol levels. CONCLUSION: The original CATCH results demonstrated that school-level interventions could modify school lunch and school physical education programs as well as influence student behaviors. This 3-year follow-up without further intervention suggests that the behavioral changes initiated during the elementary school years persisted to early adolescence for self-reported dietary and physical activity behaviors.

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.

Predictors of overweight and overfatness in a multiethnic pediatric population. Child and Adolescent Trial for Cardiovascular Health Collaborative Research Group.

The goal of the study was to determine whether overweight or overfatness were predicted from sex, race or ethnicity, school site, and intervention or control status for children who were 9 y old at the outset of the Child and Adolescent Trial for Cardiovascular Health (CATCH). In this ethnically and geographically diverse group of 5106 students, height, weight, and triceps skinfold thickness were measured at 9 (baseline) and 11 y (follow-up) of age. The strongest predictors of status at follow-up were baseline overweight (odds ratio: 69.0; 95% CI: 54.9, 96.3) and overfatness (odds ratio: 27.4; 95% CI: 22.4, 33.4); site, African American race or ethnicity, and male sex were also significant independent associations. Children in the overweight (> 85th percentile for body mass index) group had significantly higher adjusted means for total blood cholesterol, higher apolipoprotein B concentrations, lower mean HDL-cholesterol concentrations, and lower performance on the 9-min run than those in other groups (< 15th, 15-49th, or 50-85th body mass index percentiles). Similar results were found for these factors for those subjects with greater triceps skinfold-thickness measurements. Groups of children who were overweight and overfat at baseline were more likely to be overweight and overfat at follow-up and to have more cardiovascular risk factors than their peers.

The Child and Adolescent Trial for Cardiovascular Health (CATCH): intervention, implementation, and feasibility for elementary schools in the United States.

The Child and Adolescent Trial for Cardiovascular Health (CATCH) was the largest school-based field trial ever sponsored by the National Institutes of Health. The trial demonstrated positive changes in the school food service and physical education program, as well as in students' cardiovascular health behaviors. Because the CATCH intervention programs were implemented in 56 schools (in four states) that were typical of schools throughout the United States, their reception by schools and degree of implementation provide evidence about their feasibility for schools nationally. Extensive process evaluation data were collected from students, teachers, school food service personnel, and physical education specialists throughout the three school years of the CATCH intervention. Four of the CATCH programs--school food service, physical education, classroom curricula, and home programs--were assessed over the three school years. The process data provide information on participation, dose, fidelity, and compatibility of the CATCH programs in the intervention schools for these programs. High levels of participation, dose, fidelity, and compatibility were observed for the four programs during the 3 school years. CATCH emerges as a model of a feasible multilevel health promotion program to improve eating and exercise behaviors for elementary schools in the United States.

Parent and physician response to children's cholesterol values of 200 mg/dL or greater: the Child and Adolescent Trial for Cardiovascular Health Experiment.

OBJECTIVE: To determine parental actions and concerns and physician responses to parental notification that a child's cholesterol value was 200 mg/dL or greater, a value recommended by the National Cholesterol Education Program to warrant physician follow-up and evaluation. METHODOLOGY: A telephone survey of parents (n = 784) and physicians (n = 117) was carried out after parental notification of a total blood cholesterol value obtained as part of measurement done while participating in the Child and Adolescent Trial for Cardiovascular Health in 96 schools located in California, Louisiana, Minnesota, and Texas. RESULTS: Only 20% of parents contacted physicians. Factors associated with this action included whether the parent was notified once or twice, the level of the cholesterol, previous cholesterol testing in the parent, and medical insurance that covered the visit. Family history of cardiovascular disease, when other factors were considered, did not increase the likelihood that a physician contact would be made. After contact with the physician, 59% of physicians reported evaluating children for cholesterol; about half reported repeating the cholesterol determination. CONCLUSION: Parental knowledge of a child's cholesterol value of 200 mg/dL or greater did not result in substantially further seeking of health care.

Operational design and quality control in the CATCH multicenter Trial.

BACKGROUND: The Child and Adolescent Trial for Cardiovascular Health (CATCH) was the first multicenter school-based research study to employ the fundamentals of clinical trials including the standardized protocol and Manuals of Operation, a steering committee for study governance, a distributed data system, an extensive quality control system, and a Data and Safety Monitoring Board. METHOD: CATCH tested the effectiveness of changes in school lunches, physical education, smoking policy, curricula, and family activities. Ninety-six elementary schools in four states were randomized to intervention or control conditions. The baseline cohort comprised 5, 106 ethnically diverse third graders followed through fifth grade. RESULTS: The percentages of calories from fat and saturated fat were reduced significantly more in the intervention school lunches than among the controls. Significant increases in moderate to vigorous activity levels in existing physical education classes were made as well. Changes in self-reported dietary, physical activity, and psychosocial measures were significant. There were no significant differences in the physiological measures. Measurement error was generally low for all physiologic measures except skinfolds, indicating a high level of reliability. Across all sites, the coefficients of variation for lipids, height, and weight were less than 3%, whereas for skinfolds, they were considerably higher, ranging from 6 to 8%. Intraclass correlations for lipid studies were also uniformly high at 0.99. Interobserver agreement scores for SOFIT were greater than 90% for 9 of the 11 activities observed. Data entry error rates were low with less than five errors per 1,000 fields for all forms. CONCLUSIONS: The CATCH results provided more scientific evidence on the importance of schools in the population approach to health promotion. Many of the strategies used in this complex multicenter trial in the areas of design and analysis, measurement, training, data management, and quality control protocols might be appropriate for adoption in other studies.

School physical education: effect of the Child and Adolescent Trial for Cardiovascular Health.

BACKGROUND: Physical inactivity is a risk behavior for cardiovascular and other diseases. Schools can promote public health objectives by increasing physical activity among youth. METHODS: The Child and Adolescent Trial for Cardiovascular Health (CATCH) was a multicenter, randomized trial to test the effectiveness of a cardiovascular health promotion program in 96 public schools in four states. A major component of CATCH was an innovative, health-related physical education (P+) program. For 2.5 years, randomly assigned schools received a standardized PE intervention, including curriculum, staff development, and follow-up. RESULTS: Systematic analysis of 2,096 PE lessons indicated students engaged in more moderate-to-vigorous physical activity (MVPA) in intervention than in control schools (P = 0.002). MVPA during lessons in intervention schools increased from 37.4% at baseline to 51.9%, thereby meeting the established Year 2000 objective of 50%. Intervention children reported 12 more min of daily vigorous physical activity (P = 0.003) and ran 18.6 yards more than control children on a 9-min run test of fitness (P = 0.21). CONCLUSIONS: The implementation of a standardized curriculum and staff development program increased children's MVPA in existing school PE classes in four geographic and ethnically diverse communities. CATCH PE provides a tested model for improving physical education in American schools.

Changes in nutrient intakes of elementary school children following a school-based intervention: results from the CATCH Study.

BACKGROUND: Twenty-four-hour recalls were used to assess the change in nutrient intake among elementary-age school children exposed to the Child and Adolescent Trial for Cardiovascular Health (CATCH). The purpose of this paper is to compare changes in nutrient intakes between treatment groups, sexes, ethnic groups, and the four CATCH sites. METHODS: Twenty-four-hour recalls were administered to a subsample of the CATCH cohort at baseline in third grade and following the intervention in fifth grade (n = 1,182). Changes in nutrient levels for total energy, dietary cholesterol, and dietary fiber and changes in the proportion of energy from fat, protein, carbohydrate, and fatty acids were studied looking at differences by treatment group, sex, ethnicity, and site. Mixed-model analysis of variance was used to examine the change in nutrient intake, defined as intake at follow-up minus intake at baseline. RESULTS: Students in the intervention schools showed statistically significant differences in the changes in total energy and proportion of energy from total fat, saturated fat, protein, and monounsaturated fat compared with students in the control group. Students in the intervention group decreased their total fat intake from 32.7% of energy to 30.3% of energy and saturated fat from 12.8% of energy to 11.4% of energy. There were no significant differences in intervention effects by ethnic group, sex, or site. Differences in nutrient change between the school-only and the school-plus-family intervention groups were nonsignificant. CONCLUSION: The results show that a school-based intervention can positively influence children's intakes of total fat and saturated fat, suggesting that population-based approaches for reducing cardiovascular risk factors in children are feasible and effective. The results are also important in showing that the intervention was effective in Caucasian, African-American, and Hispanic students, in boys and girls, and across four regions of the United States.

The effect of adult participation in a school-based family intervention to improve Children's diet and physical activity: the Child and Adolescent Trial for Cardiovascular Health.

UNLABELLED: BACKGROUND. There are strong theoretical reasons for including a family component with a school-based intervention aimed at eating, activity, and smoking behaviors, but the empirical findings to date are limited and show mixed results. The overall CATCH family intervention added only knowledge and attitudinal effects, but no additional behavioral outcomes. This study provides a dose analysis of the family component of the CATCH study by assessing the effect of the level of adult participation. METHOD: This secondary analysis included students who attended a CATCH family intervention school during all 3 years of the study. The extent of the adult-child interaction, the key aspect of the CATCH family intervention, was measured by the number of activity packets that an adult household member completed with the child. Multiple regression analysis was used to assess the association of adult participation with the child's knowledge, attitudes, and behaviors related to diet and physical activity. RESULTS: Statistically significant results suggested that dose effects were found for knowledge and attitudes related to diet and physical activity. These effects were more pronounced for minority and male students. CONCLUSIONS: These results suggest that dose response of a family intervention has been shown in the acquisition of positive knowledge and attitudes toward health habit changes. The methodology of dose response can be applied to other health promotion projects.

Changes in the nutrient content of school lunches: results from the CATCH Eat Smart Food service Intervention.

BACKGROUND: The Child and Adolescent Trial for Cardiovascular Health (CATCH) tested the effectiveness of a multilevel intervention aimed at promoting a healthful school environment and positive eating and physical activity behaviors in children. The CATCH Eat Smart Program targeted the school food service staff and aimed to lower the total fat, saturated fat, and sodium content of school meals. METHODS: The Eat Smart intervention was conducted in 56 intervention schools over a 2(1/2)-year period.+Five consecutive days of school menu, recipe, and vendor product information were collected from intervention and control schools at three intervals, Fall 1991, Spring 1993, and Spring 1994, to assess the nutrient content of school menus as offered. RESULTS: There was a significantly greater mean reduction in the percentage of calories from total fat (adjusted mean difference -4.1%; P < 0.0001) and saturated fat (adjusted mean difference -1.3%; P = 0.003) in intervention compared with control schools from baseline to follow-up. Although the sodium content of school lunches increased in both conditions, the mean increase was significantly lower in intervention schools (adjusted mean difference -89 mg; P = 0.034). There were no statistically significant differences for total amounts of cholesterol, carbohydrate, protein, dietary fiber, total sugars, calcium, iron, vitamin A value, and vitamin C. Average total calories decreased significantly; however, the mean total calories (683 kcal) for intervention schools remained above one-third of the Recommended Dietary Allowances for this age group. CONCLUSIONS: The CATCH Eat Smart intervention successfully lowered the total fat and saturated fat content of school lunches as offered, while maintaining recommended amounts of calories and essential nutrients.

Validation of interviewer- and self-administered physical activity checklists for fifth grade students.

The purpose of the study was to evaluate two physical activity recall instruments appropriate for use in epidemiologic studies of fifth grade children. The instruments were similar, except one (PACI) was administered in a personal interview, and the other (SAPAC) was self-completed in a group setting. Both forms required children to report the minutes during the previous day they spent in 21 common physical activities that represented a range of intensities, plus sedentary pursuits. To validate the recalls, children simultaneously wore an accelerometer (motion sensor) and a heart rate monitor for at least 8 h the day before the interview. Subjects were 55 boys and 70 girls from four regions of the United States. The Pearson correlation between the self- and interviewer-administered forms was 0.76 (P < 0.001). The interviewer-administered form correlated 0.51 (P < 0.001) with the heart rate index and 0.33 (P < 0.001) with the accelerometer score. The self-administered form correlated 0.57 (P < 0.001) with the heart rate index and 0.30 (P < 0.001) with the accelerometer score. It is concluded that both self-report forms received moderate support for their validity in all gender and ethnic subgroups. The self-administered format is more cost-effective.

The effects of the Child and Adolescent Trial for Cardiovascular Health upon psychosocial determinants of diet and physical activity behavior.

BACKGROUND: The Child and Adolescent Trial for Cardiovascular Health is a multisite study of a school-based intervention to reduce or prevent the development of risk factors for cardiovascular disease. The purpose of this paper is to present the evaluation results of the 3-year intervention, focusing upon the psychosocial variables conceptualized as determinants of dietary and physical activity behaviors. METHODS: A total of 96 schools across four study sites (California, Louisiana, Minnesota, and Texas) were randomized to two treatment conditions: intervention and control. Pre- and postmeasurements on the health behavior questionnaire were collected from over 6,000 students. The data analyses utilized a nested design approach in which schools served as the primary unit of analysis. Repeated-measures multivariate analyses were applied to investigate effect sizes for each determinant and to explore theoretical relationships among the determinants over time. RESULTS: The findings indicated sustained significant effects in improved knowledge, intentions, self-efficacy, usual behavior, and perceived social reinforcement for healthy food choices (P < 0.0001 for these five variables) after 3 years. Intermittent effects were observed for perceived support and self-efficacy for physical activity. No gender by determinant interaction effects were observed, and girls reported significantly greater perceived reinforcement for healthy eating than did boys. CONCLUSION: The CATCH program was effective in changing the psychosocial variables likely to influence a reduction in behavior for cardiovascular disease. The study is significant in that it demonstrates the viability and effectiveness of a sustained multifaceted intervention in a preadolescent population. The results point to a need for greater understanding of adolescent developmental issues and the role of community environment (particularly social support) in creating effective curricula.