Chyrise B. Bradley

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 childrens 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.

Changes in common activities of 3rd through 10th graders: the CHIC study.

PURPOSE This study was a longitudinal examination of the change in both the activities done and the intensity of those activities from childhood to adolescence. METHODS Common activities were assessed by questionnaire initially on 656 subjects from 21 elementary schools; 50.5% were female, 83.4% were Caucasian, 20.6% African-American, and 6.0% were other races. RESULTS Girls more often reported sedentary activities overall. Weighted least squares analyses showed boys consistently reported more vigorous activities than girls (P < 0.0008). African-American girls reported fewer vigorous activities than Caucasian or other race girls (P = 0.027). Sedentary activities were more frequently reported with increasing age (X2 P < 0.001). The youngest African-American and Caucasian boys reported similar activity patterns. However, boys from other races reported more intense activities until sixth and seventh grades when African-American boys began reporting more sedentary activities than Caucasians or other races (P = 0.004). During sixth-eighth grades, Generalized Estimating Equations (GEE) models show that girls with more advanced pubertal status reported more sedentary activities than girls who were less developed (P < 0.0001). For high school girls, race was a marginally significant predictor (P = 0.05) of activity status. Neither race nor pubertal status were significant factors in activities chosen by middle school boys. However, for male high school students, Caucasians were more likely than African-Americans to report vigorous activities (P = 0.005). CONCLUSIONS Variation in activities by race within gender suggests that establishing activity patterns in youth may be race-specific as well as gender-specific and must be accounted for in designing physical activity interventions. Also, pubertal maturation is a factor in activity choices in middle school girls.

School-based Interventions Improve Heart Health in Children With Multiple Cardiovascular Disease Risk Factors

Objective. To determine the immediate effects of two types of elementary school-based interventions on children with multiple cardiovascular disease (CVD) risk factors. Design. Randomized, controlled field trial. Setting. Conducted in 18 randomly selected elementary schools across North Carolina. Study Participants. Four hundred twenty-two children age 9 ± 0.8 years with at least two risk factors at baseline: low aerobic power and either high serum cholesterol or obesity. Intervention. Both 8-week interventions consisted of a knowledge and attitude program and an adaptation of physical education. The classroom-based intervention was given by regular teachers to all children in the 3rd and 4th grades. The risk-based intervention was given in small groups only to children with identified risk factors. Children in the control group received usual teaching and physical education. Outcome Measures. The primary outcome measure was cholesterol; additional measures were blood pressure, body mass index, body fat, eating and activity habits, and health knowledge. Results. Both interventions produced large reductions in cholesterol (−10.1 mg/dL and −11.7 mg/dL) compared with a small drop (−2.3 mg/dL) in the controls. There was a trend for systolic blood pressure to increase less in both intervention groups than in the controls. Both intervention groups had a small reduction in body fat and higher health knowledge than the control group. Conclusions. Both brief interventions can improve the CVD risk profile of children with multiple risk factors. The classroom-based approach was easier to implement and used fewer resources. This population approach should be considered as one means of early primary prevention of CVD.

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.

LEISURE TIME ACTIVITIES OF ELEMENTARY SCHOOL CHILDREN

The three most common leisure time activities of 2,200 third and fourth grade children (mean age 8.8 + 0.8; 50.7% girls) and the association of the intensity levels of those activities with demographic variables and risk factors for cardiovascular disease are reported. Activities reported most often by boys were playing video games (33%), playing football (32%), bicycling (31%), watching television (28%), and playing basketball (26%). The girls reported doing homework (39%), bicycling (31%), watching television (30%), dancing (27%), and reading (23%). Overall, the children, especially girls, reported fairly sedentary activities, with an average metabolic equivalent level of 4.2 for girls and 4.8 for boys. Among boys, African Americans reported more vigorous activities than Whites, but the activities reported by White girls were somewhat more vigorous than those reported by non-White girls. Children from a higher socioeconomic status (SES), especially boys, reported a greater proportion of sedentary activities than lower SES children. The risk factors of cholesterol, blood pressure, skinfold thickness, and body mass index were not significantly associated with total activity score. However, significantly more nonobese than obese children reported a vigorous (high-intensity) activity as one of their top three activities.

A food frequency questionnaire for youth: psychometric analysis and summary of eating habits in adolescents

PURPOSE To examine the reliability and validity of the Eating Habits Questionnaire (EHQ) for adolescents and assess eating habits in the context of the Food Pyramid. METHODS Subjects were 446 students (81.2% female) attending three middle schools (sixth to eighth grades). Over half (56.9%) were African-American. Reliability was assessed with 48-h and 2-week retests on two subsamples (n = 62) and validity was assessed by comparison with three 24-h recalls on an additional subsample (n = 24) and by factor analysis. The EHQ is a self-administered questionnaire consisting of 83 food items and questions assessing food habits and food preparation style. RESULTS Internal validity, determined with factor analysis, found that 10 factors explained 81.3% of the variance in eating habits. Overall perfect agreement between food groups reported on the 24-h recall and on the EHQ was 56%. Internal consistency, assessed by Cronbach alpha, ranged from .60 to .89. Test-retest correlations were highest at 48 h, ranging from .46 to .85 for the 10 factors. Adolescents ate more servings of fats and sugars (11.2) and meats (6.0) and fewer breads (5.2) and vegetables (1.6) than recommended in Food Pyramid guidelines. In addition, subjects consumed more high-fat protein than low-fat protein servings. CONCLUSIONS The EHQ is a valid and reliable food frequency questionnaire that has been tested with African-American and white adolescents in the Southeast. It showed that adolescents consume higher than recommended daily servings of fats, sweets, and meats and lower than recommended servings of vegetables and breads.

Assessing Physical Activity in Adolescents: Common Activities of Children in 6th–8th Grades

Objectives To provide data for physical activity assessment in practice by describing the leisure time activ‐ities of adolescents and determining if the activities and the metabolic equivalents (MET levels) of those activities differ for boys and girls. Data Sources The study was conducted in five middle schools in three rural counties in North Carolina. Subjectswere 1,211 6th, 7th, and 8th graders aged 11–14 (mean 12.2) years. Half (52.5%) were girls. The sample was 64% white, 24% African‐American and 12% other races. Results The top five activities of boys were football, basketball, bicycling, running, and baseball; the top five activities of girls were talking, running, walking, bicycling, and dancing. The average MET was 5.3 for boys and 4.3 for girls (p=0.000). By grade levels, 6th graders had an average MET of 4.9 and the MET of 8th graders was 4.5 (p<0.05). Older youth, girls, and children of parents with more education reported significantly more sedentary activities than the other youth. Implications for Practice Physical activity is an integral component of overall health. Once activities and activity levels are known, current practices can be aug‐mented or changed to accommodate improved understanding of physical activity. Because an active lifestyle is important in preventing obesity and other chronic conditions and for general health, nurse practitioners (NPs) should ask adolescents about their common activities and encourage them to continue the more vigorous activities and reduce time spent in sedentary pursuits. Prescriptive physical activity can be included for primary, secondary, or even tertiary prevention, thus crossing all levels of NP practice.

Comparison of a computerized physical activity recall with a triaxial motion sensor in middle-school youth.

PURPOSE To develop and test a computerized activity recall (CAR) for capturing activity and energy expenditure (EE) in youth and to further our understanding of the use of the three-dimensional accelerometer (Tritrac) for studying activity and EE. METHODS Forty-five students (25 girls and 20 boys) in grade 6-8, completed 5 consecutive days of the CAR and were randomly assigned to wear the Tritrac during 1 day in which they also completed the CAR. Twenty-two subjects also repeated 5 d of the CAR and 1 d of Tritrac monitoring 1-2 wk later. RESULTS The correlation between CAR and Tritrac for total EE was significant (r = 0.510, P = 0.0003). However, the total EE computed from the Tritrac was significantly greater than the CAR (1941 +/- 273 kcal vs 1576 +/- 343 kcal (8.14 +/- 1.14 vs 6.60 +/- 1.44 MJ); P < 0.001). The EE of activities was similar for the Tritrac and CAR, approximately 670 kcal (2.80 MJ), suggesting that the difference between the two methods was their estimates of resting EE. Comparison of the CAR and Tritrac for classifying active and inactive subjects indicated that both methods similarly classified 35 of the 45 subjects or 78% (P = 0.0038). Although significant, the Kappa statistic (kappa = 0.398) indicated a low-level of agreement between methods. The Tritrac indicated 50.4 +/- 29.2 min.d-1 of activities of > or = 3 METs, whereas the CAR indicated 76.7 +/- 71.9 min.d-1 (P = 0.02). The week 1 vs 2 test-retest correlation was 0.0485 (P = 0.022) for the Tritrac and 0.820 (P = 0.0001) for the CAR. CONCLUSIONS It appears that both methods have acceptable reliability. However, the validity of each method to measure total and activity EE remains unclear, as the Tritrac appears to overestimate resting energy expenditure, whereas the CAR overestimates total minutes of activity.

Cigarette use in adolescents: The cardiovascular health in children and youth study

Tobacco is the leading cause of preventable death in the United States, and its use is increasing in adolescents. To determine the interventions needed to prevent the initiation of smoking, it is important to know the factors related to tobacco use by adolescents. In this study the following factors related to cigarette use were examined: age, gender, ethnicity, self-esteem, physical activity, parental smoking, and socioeconomic status. Participants were 1,207 youth completing a written survey for the Cardiovascular Health in Children and Youth Study (CHIC II). Participants ranged in age from 10 to 15 years, with a mean age of 12.2 years; 64.2% were White, 24.0% Black, 5.8% Hispanic, and 6.0% other races. White and Hispanic youth and youth of other races had significantly higher rates of smoking than did Black youth. Significant risk factors for smoking were: higher grade in school, White race, and for girls only, lower self-esteem. In White youth those in the lowest socioeconomic status were most likely to be current and experimental smokers. Smoking was as common in girls as in boys at these ages. Multivariate analysis showed that neither physical activity nor parental smoking were significant predictors of smoking behaviors. These results suggest that smoking prevention programs for adolescents should specifically target White and Hispanic youth and those from families with low socioeconomic status. In addition, these interventions should include ways to increase self-esteem in girls.

Predicted maximal aerobic power in youth is related to age, gender, and ethnicity.

PURPOSE To determine the effects of age, gender, and ethnicity on the predicted aerobic power of youth as they age from 8 to 16 yr. METHODS The sample was a multicohort group of 2540 African Americans (N = 543) and Caucasians (N = 1997), 1279 (50.4%) girls and 1261 (49.6%) boys. Heights, weights, and sum of skin folds (triceps + subscapular) were measured. Aerobic power ((p)VO(2max)), expressed in relative (mL x kg(-1) x min(-1)) or absolute (L x min(-1)) terms, was predicted from a three-stage cycle ergometry test. RESULTS Quadratic mixed-model analysis indicated that boys had higher relative and absolute (p)VO(2max) than the girls (P = 0.0004). The African American subjects had a higher absolute (p)VO(2max) (L x min(-1)) than the Caucasians, but their relative (p)VO(2max) was lower than the Caucasians (P = 0.031). Finally, age had a significant effect on (p)VO(2max) (P = 0.0001). The absolute (p)VO(2max) of the girls increased 9%.yr(-1) until age 14; but their relative (p)VO(2max) declined approximately 1.2 mL x kg(-1) x min(-1) x yr(-1). The absolute (p)VO(2max) for the boys increased yearly by approximately 14% from ages 8 to 16 yr, but the relative (p)VO(2max) of the African American males was stable from ages 8 to 11, then dropped, and stabilized again between ages 12 and 16 yr. The relative (p)VO(2max) of the Caucasian boys declined from ages 8 to 10, but then increased slightly from age 12 to 16 yr. In addition, the interactions of age and gender, and age squared and gender were significant (P < 0.02). CONCLUSION These data indicate that although absolute (p)VO(2max) (L x min(-1)) increases from age 8 to 16 yr, relative (p)VO(2max) (mL x kg(-1) x min(-1)) declines. The decline appears to be related to increased fat mass. Similarly, the higher relative (p)VO(2max) (mL x kg(-1) x min(-1)) of the Caucasian youth compared with the African American youth was related to lower weights and skin folds of the Caucasian youth.