Bullied status and physical activity in Texas youths

Data from the 2009–2011 School Physical Activity and Nutrition (SPAN) project were analyzed to examine the association between bullied status at school during the past six months and engaging in five or more days of physical activity during the past seven days in a population of 8th and 11th grade Texas youths after stratifying by gender. As a secondary aim, this study also examined the association between weight status and the prevalence of bullied status at school. The final sample size for this study, after excluding missing data, consisted of 6,246 8th and 11th grade youths (girls, n= 3,237; boys, n=3,009) representing a total of 518,838 youths from 8th and 11th grade. Results from the multiple logistic regression adjusting for weight status, grade, and ethnicity, indicate that girls with a bullied status of at least two or three times per month had significantly lower odds of engaging in five or more days of physical activity during the past seven days than girls who were never bullied at school (ORadj=0.62; 95% CI, 0.40, 0.96). Conversely, girls who reported a bullied status of at least once per week were significantly more likely to engage in five or more days of physical activity during the past seven days compared to girls who were never bullied at school (ORadj=3.44; 95% CI, 1.56, 7.63). No significant associations between bullied status and engaging in five or more days of physical activity during the past seven days were found for boys. Bullied status differed significantly across weight status for 8th grade girls (χ2(6)=63.7, p<.05) and 11th grade boys (χ2(6) =94.93, p<.05), with overweight and obese youths reporting a higher prevalence of being bullied once or twice, at least two or three times per month, and at least once per week than their normal weight peers. Our finding that girls with bullied status of at least once per week were more likely to engage in five or more days of physical activity than girls who were never bullied warrants future qualitative research to identify potential explanations for such results. Future research on relational and weight-based bullying is also needed and may help explain the inconsistent findings between bullied status and engaging in physical activity in girls.^

Team: Bee Me. A formulative evaluation of a negative eating attitudes and behaviors primary prevention curriculum targeted at 5 th grade elementary school girls

Objective. To evaluate a school-based intervention aimed at the primary prevention of negative eating attitudes and behaviors among preadolescent girls, and to revise curriculum lessons based on quantitative and qualitative findings. ^ Intervention Design. A formative evaluation was conducted on four Team: Bee Me curriculum lessons at a Houston elementary school. Evaluation focused on program satisfaction and short-term effect on knowledge and eating attitudes and behaviors. ^ Results. Sixteen girls participated in the five-day project. Statistically significant improvements in overall knowledge were observed (p<0.05), however only modest changes were observed in eating attitudes and behaviors. Program satisfaction was high among student participants and the teacher who implemented it. Insight for future modifications to this program and for similar interventions was provided by the students and teacher. ^ Conclusions. This program led to positive trends in outcome variables; however longer and more intensive testing of this program is needed to better evaluate its effectiveness.^

Analyzing the Role of αvβ8 Integrin in Glioma-Induced Angiogenesis

In this study we aimed to determine the functional roles for αvβ8 integrin in astrocytoma-induced angiogenesis. These studies originate from our analyses of αvβ8 integrin in developmental brain angiogenesis. αv and β8 knockout (KO) mice develop brain-specific vascular phenotypes that resemble vascular pathologies observed in the malignant astrocytoma, glioblastoma multiforme (GBM). Indeed, a murine xenograft model of astrocytoma suggested a role for the integrin in glioma-induced angiogenesis. Primary mouse astroglia were cultured from wild type (WT) and β8 KO neonates and were immortalized (HPV:E6/E7) and transformed (HRas:G12V). WT and β8 KO transformed astroglia were intracranially injected into athymic mice. WT tumors displayed pathological features of grade III astrocytomas, whereas β8 KO tumors resembled grade IV GBMs. KO tumors contained widespread edema and hemorrhage as well as pathological angiogenesis, as assessed by quantitation of microvascular density and blood vessel morphology. Additionally, exogenous expression of β8 integrin in β8 KO transformed astroglia resolved the pathologies observed in KO tumors giving further credence to the idea that loss of αvβ8 integrin expression correlates with tumorigenic potential of oncogene-transformed astroglia. To compliment our mouse model, several established human glioma cell lines were characterized for expression of αvβ8 integrin protein. Some of the cell lines displayed low expression of αvβ8 integrin, whereas others showed high levels, as compared to non-malignant human astrocytes. Intracranial implantation of high and low β8 integrin-expressing human glioma cell lines resulted in tumors exhibiting similar phenotypes to those observed in the mouse model; low expressers were marked by vascular pathologies indicative of β8 KO mouse tumors. Upon overexpression of β8 integrin in a low β8 integrin-expressing human glioma cell line, angiogenic pathologies were largely resolved. Moreover, intracranially injected αvHI- and αvLO-sorted GBM stem cells (GSCs) resulted in significantly different tumor sizes, where those GSCs endogenously expressing low levels of αv integrin formed two to three fold larger tumors. Furthermore, lentiviral knockdown of β8 integrin in transformed human astrocytes formed tumors that strikingly recapitulated the characteristics of the murine β8-/- tumors, exhibiting a significant increase in microvascular density leading to decreased overall survival. A paracrine mechanism was discovered involving endothelial cell homeostatic control governed by canonical TGFβ signaling initiated by αvβ8 integrin’s role in the latent cytokine’s activation. Diminished TGFβ signaling in tumor-associated endothelial cells promoted increased angiogenesis and decreased overall survival as a result of αvβ8 integrin’s loss on the tumor cell. Collectively, these data suggest an important functional role for αvβ8 integrin in glioma angiogenesis.

Psychosocial and environmental predictors of calcium intake, physical activity and bone health among adolescent girls

Objectives. The purpose of this study was to identify the psychosocial and environmental predictors and the pathways they use to influence calcium intake, physical activity and bone health among adolescent girls. Methods. A secondary data analysis using a cross-sectional and longitudinal study design was implemented to examine the associations of interest. Data from the Incorporating More Physical Activity and Calcium in Teens (IMPACT) study collected in 2001-2003 were utilized for the analyses. IMPACT was a 1½ year nutrition and physical activity intervention study conducted among 718 middle-school girls in central Texas. Hierarchical regression modeling and Structural Equation Modeling (SEM) were used to determine the psychosocial predictors of calcium intake, physical activity and bone health at baseline. Hierarchical regression was used to determine if psychosocial factors at baseline were significant predictors of calcium intake and physical activity at follow-up. Data was adjusted for included BMI, lactose intolerance, ethnicity, menarchal status, intervention and participation in 7th grade PE/athletics. Results. Results of the baseline regression analysis revealed that calcium self-efficacy and milk availability at home were the strongest predictors of calcium intake. Friend engagement in physical activity, physical activity self-efficacy and participation in sports teams were the strongest predictors of physical activity. Finally, physical activity outcome expectations, social support and participation in sports teams were significant predictors of stiffness index at baseline. Results of the baseline SEM path analysis found that outcome expectations and milk availability at home directly influenced calcium intake. Knowledge and calcium self-efficacy indirectly influenced calcium intake with outcome expectations as the mediator. Physical activity self-efficacy and social support had significant direct and indirect influence on physical activity with participation in sports teams as the mediator. Participation in sports teams had a direct effect on both physical activity and stiffness index. Results of regression analysis for baseline predicting follow-up showed that participation in sports teams, self-efficacy, outcome expectations and social support at baseline were significant predictors of physical activity at follow-up. Conclusion. Results of this study reinforce the relevance of addressing both, psychosocial and environmental factors which are critical when developing interventions to improve bone health among adolescent girls. ^

Does parental monitoring influence the use of alcohol and drugs among inner city 7th grade students?

Objective. To examine associations between parental monitoring and adolescent alcohol/drug use. ^ Methods. 981 7th grade students from 10 inner-city middle schools were surveyed at the 3 month follow-up of an HIV, STD, and pregnancy prevention program. Data from 549 control subjects were used for analyses. Multinomial logistic regression was used to examine associations between five parental monitoring variables and substance use, coded as: low risk [never drank alcohol or used drugs (0)], moderate risk [drank alcohol, no drug use (1)], and high risk [both drank alcohol and used drugs or just used drugs (2)]. ^ Results. Participants were 58.3% female, 39.6% African American, 43.8% Hispanic, mean age 13.3 years. Lifetime alcohol use was 47.9%. Lifetime drug use was 14.9%. Adjusted for gender, age, race, and family structure, each individual parental monitoring variable (perceived parental monitoring, less permissive parental monitoring, greater supervision (public places), greater supervision (teen clubs), and less time spent with older teens) was significant and protective for the moderate and high risk groups. When all 5 variables were entered into a single model, only perceived parental monitoring was significantly associated (OR=0.40, 95% CI 0.29-0.55) for the moderate risk group. For the high risk group, 3 variables were significantly protective (perceived parental monitoring OR=0.28, CI 0.18-0.42, less time spent with older teens OR=0.75, CI 0.60-0.93, and greater supervision (public places) OR=0.79, CI 0.64-0.99). ^ Conclusion. The association between parental monitoring and substance abuse is complex and varied for different risk levels. Implications for intervention development are addressed. ^

The association of food sources of calcium with weight class in adolescent girls

To determine the association of food sources of calcium with weight class in adolescent girls, the major food sources of calcium were determined for 718 sixth grade girls at three different time periods during an 18 month school-based health intervention program using a FFQ. To determine weight class, the BMI of each girl was stratified using CDC age and gender specific criteria at each time period. The percent contribution of the major food sources of calcium to total calcium intake was compared among the different weight classes at each time period, among those girls who had changed weight class at the different time periods and for those girls who did not change weight class at the different time periods. The mean total calcium intake increased by 20% between the first two time periods and by 12% between the first and last time periods with the intervention despite baseline total calcium intake already being greater than the recommended 1300 mg/day. The percent contribution of the major food sources of calcium were highly correlated among the weight classes that were compared throughout the study. Those girls who remained in the normal weight class throughout the study had the most consistent intake of food sources of calcium. Their top four food sources of calcium were different types of milk which provided greater than 50% of their total calcium intake. Despite there being no significant differences in the major food sources of calcium among the different weight classes, these data show a successful intervention for increasing calcium intake among adolescent girls. ^

Development and evaluation of a nutrition education program designed to increase fruit and vegetable consumption in girls, ages 9--12

The purpose of this study is to evaluate the theory-based Eat 5 nutrition badge. It is designed to increase fruit and vegetable (F&V) intake in 4th-6th grade junior Girl Scouts. Twenty-two troops were recruited and randomized by grade level (4th, 5th, 6th, or mixed) into either the intervention or control conditions. The leaders in the intervention condition received a brief training and the materials and conducted the program with their troops during four meetings. The Girl Scouts in the intervention condition completed 1-day Food Frequency Questionnaires and Nutrition Questionnaires both before and after completing the Eat 5 badge, and a third measurement of F&V intake three months after the posttest. Girl Scouts in the control condition were only evaluated at the three time periods.^ The primary hypotheses were that the Girl Scouts in the intervention condition would increase their daily intake of fruits and vegetables at both the posttest and three months later, compared to the Girl Scouts in the control condition. Other study questions investigated the impact of the Eat 5 program on intervening variables such as knowledge, self-efficacy, barriers, norms, F&V preference, and F&V selection and preparation skills.^ A nested ANOVA, with troop as the unit of analysis nested within condition, was used to assess the effects of the program. Pretest F&V intake and grade level were used as covariates. Pretest mean F&V intake for the total sample of 210 girls was 2.50 servings per day; 3.0 for the intervention group (n = 101). Significant increases in F&V intake (to 3.4 servings per day), knowledge, and fruit and vegetable preference were found for the intervention condition troops compared to the troops in the control condition. Three months later, the mean F&V intake had returned to pretest levels.^ This study indicates that social groups such as Girl Scouts can provide a channel for nutrition education. Long term effects were not sustained by the intervention; a possible cause was the lack of change in self-efficacy. Therefore, additional interventions are recommended such as booster lessons to maintain increased F&V intake by Girl Scouts. ^

The heart challenge: The effect of regular aerobic exercise on body fat distribution in third and fourth grade school children: A randomized clinical trial

The pattern of body fat distribution known as "centralized", and characterized by a predominance of subcutaneous fat on the trunk and a "pot belly", has been associated with an increased risk of chronic disease. These patterns of fat distribution, as well as the lifestyle habit variables associated with adult fatness and chronic morbidity clearly begin to develop during childhood, indicating the need for intervention and primary prevention of obesity, particularly the centralized form, during childhood or adolescence. The purpose of this study was to determine whether regular aerobic exercise could beneficially alter the distribution of body fat in 8 and 9 year old children. One hundred and eighty-eight participants were randomized into either a regular aerobic exercise treatment group or a standard physical education program control group. A variety of aerobic activities was used for intervention 5 days per week during physical education class for a period of 12 weeks. Fat distribution was measured by a number of the most commonly used indices, including ratios of body circumferences and skinfolds and indices derived from a principal components analysis. Change over time in average pulse rate was used to determine if intervention actually occurred. Approximately 10% of the students were remeasured, allowing the calculation of intra- and interexaminer measurement reliability estimates for all indices.^ This study group was comparable to the U.S. population, though the study children were slightly larger for certain measures. No effect of the exercise intervention was found. The most likely explanation for this was inadequacy of the intervention, as indicated by the lack of any change in average pulse rate with treatment. The results of the measurement reliability analysis are reported and indicate that body circumference ratios are more precise than skinfold ratios, particularly when multiple observers are used. Reliability estimates for the principal component indices were also high.^ It remains unclear whether the distribution of body fat can be altered with exercise. It is likely that this issue will remain undecided until one highly reliable, valid, and sensitive measure of fat distribution can be found. ^

The role of youth sports in public health

Study 1: Schools provide a range of opportunities for youth to be active, however, over the past decade, these opportunities have been declining. Sports teams are a promising venue to promote physical activity yet limited research has examined the gender an ethnic differences in sport participation. The purpose of this study is to examine trends in sport participation from 1991-2009 among US high school students. Secondly, we examined the association between gender and ethnicity with sports over time. This serial cross-sectional study used surveillance data from the Youth Risk Behavior Survey, a probability based sample weighted to represent gender and race/ethnic subpopulations of US high school students. The findings of this paper reveal persistent gender and ethnic disparities for sports participation among US youth. Since sports teams may provide a substantial source of physical activity, greater efforts should be undertaken to increase the participation of girls, especially minorities, in sports teams. ^ Study 2: Sports team participation is congruent with teaching and supporting healthy eating, yet limited research has examined the association between sports participation and dietary behaviors. This study aims to determine the association between youth sports participation and dietary behaviors among elementary-aged children. Significant dose-response associations were observed between number of sports teams and consumption of most fruits and vegetables. The likelihood of eating fruit for boys increased with the number of sports teams (1 team: OR=1.89; 3 teams: OR=3.44, p<0.001) and the likelihood of consuming green vegetables for girls was higher with the number of sports teams (1 team: OR=1.50; 3 teams: OR=2.39; p<0.001). For boys, the odds of consuming fruit-flavored drinks was higher ( p=0.019) and the odds of drinking soda was lower (p=0.018) with participation in increasing number of sports teams whereas for girls, sports participation was positively associated with diet soda consumption (p=0.006). ^ Study 3: Parents and peers have been shown to have a strong influence over the physical activity, dietary, and sedentary behaviors of youth. Youth sports teams have the potential to offer physical activity, displace sedentary behaviors, and promote a healthy diet. The purpose of this study is to assess how peer and parental support for physical activity and healthy eating, coupled with sport participation, is associated obesity related risk factors including diet and sedentary behaviors. A secondary analysis of data from the School Physical Activity and Nutrition study, a state-representative survey, was conducted. Eighth (n=3,931) and 11th (n=2,785) grade students were categorized into four groups based upon the level of peer and parental support derived from a three item scale and their participation in sports (sports/high support, sports/low support, no sports/high support, no sports/low support). Linear models were conducted to determine the difference in means between these groups for the following outcome variables: previous day fruit and vegetable intake, scores for an unhealthy and healthy food index, and hours spent watching television, playing video games, and working on a computer. Eighth graders had significantly greater levels of parental support for healthy eating and physical activity compared to 11th grade. Both 8 th and 11th graders in the sport/high support for healthy eating from peers and parents scored significantly higher on the healthy food index than other groups. Eighth and 11th graders in the sport/high support for physical activity from peers participated in fewer hours of sedentary behaviors than any other group (p ≤ 0.032). Although it is thought that sport participation may offer opportunities to support a healthy diet and displace sedentary time by offering providing physical activity, our study found that parental and peer support for activity and healthy eating may further attenuate this association. Parents and peer support should be an important target when developing strategies to improve healthy diets and reduce sedentary time among youth, especially in the context of youth sports. (Abstract shortened by UMI.)^