Steve Kelder

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.

The CATCH Kids Club: a pilot after-school study for improving elementary students’ nutrition and physical activity

BACKGROUND Although many school-based diet and physical activity interventions have been designed and evaluated, relatively few have been tested for the after-school setting. After-school day-care programmes at either elementary schools or private locations provide a ready-made opportunity for health programmes that may be difficult to incorporate into an already-full school day. The purpose of this paper is to report on a pilot study of an after-school adaptation of the CATCH (Coordinated Approach To Child Health) elementary school programme called the CATCH Kids Club (CKC). METHODS The CKC was pilot-tested and formatively evaluated in 16 Texas after-school programmes: eight in El Paso and eight in Austin (four intervention and four reference sites each). Evaluation consisted of direct observation of moderate to vigorous physical activity during play time, self-reported food intake and physical activity, and focus group interviews with after-school programme staff. RESULTS Students responded well to the physical activity and snack components and were less interested in the five-module education component. Routine staff training was a key variable in achieving proper implementation; the ideal would be a full day with repeated follow-up model teaching visits. Staff turnover was a logistic issue, as was programme leader readiness and interest in conducting the programme. Strong and significant effects were observed for the physical activity but not for the education component. The results of the physical education component suggest it is feasible, effective and ready for larger-scale evaluation or dissemination.

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.

Serum cholesterol levels in children are associated with dietary fat and fatty acid intake

BACKGROUND Recent studies in adults suggest that individual dietary fatty acids differ markedly in their effects on serum lipids and lipoprotein levels. However, these associations have rarely been studied in children. OBJECTIVE To assess, using regression procedures, the associations in children between specific fatty acids and nonfasting serum lipids and cholesterol after controlling for total energy and total fat intake, SUBJECTS The sample consisted of 1,182 children who participated in the Child and Adolescent Trial for Cardiovascular Health. The sample was equally distributed across 4 sites (Louisiana, Texas, Minnesota, California). The sample was 48% boys; 71% white, 15% Hispanic-American, 10% African-American, 2% Asian, and 2% from other or unspecified racial/ethnic heritage. DESIGN In this randomized multicenter trial with 56 intervention and 40 control elementary schools, food record-assisted 24-hour dietary recalls and serum lipid measurements were collected for each child at baseline (3rd grade) and at the 5th grade follow-up. STATISTICAL ANALYSES Repeated-measures analysis of variance was used to evaluate the association between nutrient composition of the diet and serum lipids. Independent dietary variables included amount and type of fat, individual fatty acids, protein, carbohydrate, and fiber. The dependent variables were the absolute values of serum total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) both at baseline (3rd grade) and at follow-up (5th grade). RESULTS Increased total fat (b=0.053; P<.03) was associated with increased TC in the model when energy was held constant, whereas increased carbohydrate was associated with decreased TC (b=-0.021, P<.02) and HDL-C (b=-0.010, P<.005) levels. Increased total protein (b=0.017, P<.05) was associated with increased HDL-C when energy was held constant. Saturated fat (b=0.004, P<.04), unsaturated fat (b=0.004, P<.03), and myristic fatty acid (b=0.021, P<.01) all increased TC in the model when total fat and total energy were held constant. CONCLUSIONS/APPLICATIONS We conclude that using a modeling approach, the effect of diet on serum lipids in children is similar to that observed in adults. Total fat and saturated fat were positively associated with TC and HDLC levels, saturated fat was positively associated with TC, and carbohydrate was inversely associated with both TC and HDL-C. In the statistical model, substitution of unsaturated fatty acids, monounsaturated fatty acids, or oleic acid for saturated fat, while holding total fat and energy constant, slightly lowered TC. In contrast, substitution of total fat for carbohydrate in the model increased TC and, thus, did not seem to be associated with an apparent health advantage except for HDL-C elevating effects. However, consumption of individual fats tends to be highly correlated, and we were unable to determine if these biological effects were operating independently.

Change in the Manifestation of Overt Aggression During Early Adolescence Gender and Ethnicity

This study examined how the manifestation of overt aggression changes during early adolescence using Hierarchical Linear Modeling. The distinct courses of physical and verbal aggression identified in this study provide support for developmental transformations in overt aggression, which would have been obscured unless aggression had been defined with greater specificity. The examination of gender effects revealed that while boys demonstrate higher initial levels of physical and verbal aggression, there were no gender differences in the growth of physical and verbal aggression. In addition, the testing of ethnicity effects demonstrated that Blacks and Hispanics show higher initial levels of physical and verbal aggression than Whites, however, adolescents from other ethnicities did not differ from Whites in terms of initial aggression levels. Despite the significant differences in initial status, ethnicity did not significantly predict the growth of aggression with the exception that Blacks exhibited a faster rate of decline in physical aggression. The limitations of this study and the implications for future research and practice are discussed.

A Cross-National Comparison of Youth Risk Behaviors in Latino Secondary School Students Living in El Salvador and the USA

Objectives. As Latin Americans’ exposure to the USA increases through migration patterns and US political and economic ties to their countries of origin, they become susceptible to adopting not only the cultural expressions of the USA such as fashion, but also the health-related behaviors of the US population. In assessing potential health risks for Salvadoran youth that may result from the connection between Latin Americans and the USA, this study compared the prevalence of health risk behaviors from four behavior domains (aggression and victimization, depression and suicidal ideation, substance use, and sexual behavior) between Salvadoran and US Latino secondary school students aged 14–17 years. Design. A secondary analysis was performed on two 1999 cross-sectional survey data. In the USA, results were based on 1,063 Latino high school students who answered the nationally representative Youth Risk Behavior Survey (YRBS) conducted by the Centers for Disease Control and Prevention. In El Salvador, results were based on 793 public secondary school students who answered a local YRBS survey conducted in coordination with the Ministry of Education of El Salvador. Results. The prevalence rates for aggression/victimization and for depression and suicidal ideation behaviors were similar between Salvadoran and US Latino adolescents. Substance use prevalence, however, was 10–40% higher for US Latino adolescents. While the prevalence of sexual intercourse was higher among US Latino youth (between 13 and 27% higher, depending on age), the prevalence of condom use was lower among sexually active Salvadoran youth (between 11 and 42% lower, depending on age). Conclusions. In the context of the transnationalization of the Salvadoran population, with potential for increased influence of the USA in Salvadoran culture, these differences in risk behavior are important for targeting effective interventions for Latino adolescents in El Salvador and in the USA.

Youth Exposure to Community Violence: Association with Aggression, Victimization, and Risk Behaviors

ABSTRACT The purpose of this study was to examine the association between exposure to community violence and aggression, victimization, and risk-taking behaviors among young adolescents. Secondary analysis was conducted on data from a cross-sectional survey of 8,259 sixth, seventh, and eighth grade students from eight urban schools in Texas. Results indicated that students exposed to a high level of community violence were 7.7 times more likely to carry a handgun, 5.2 times more likely to be involved in a gang were 6.4 times more likely to use marijuana, 5.3 times more likely to binge drink, and 2.8 times more likely to be injured as a result of fighting. This suggests the need for an interdisciplinary approach to violence prevention that targets all the environments of youth, including schools, homes, neighborhoods, and other community units.

Beliefs and social norms about ephedra onset and perceived addiction among college male and female athletes.

In Spring 2003, a qualitative approach was used to investigate relevant beliefs and norms associated with ephedra initiation and perceived addiction to the drug among 43 primarily minority athletes, attending a historically Black university in the southwestern region of the United States, who self-identified as past users. In general, participants stated that their second ephedra use event occurred on the same day as or the day after initiation. The majority of participants perceived that addiction was established by routine and eccentric behavior. Male athletes stated they used ephedra for improved athletic performance while females stated they used the drug for weight loss. Male participants stated it is difficult to quit ephedra use because of the resulting decrease in athletic performance, sickness, and weight gain. Female athletes were more concerned with their appearance. These findings are important in determining the early extent to which addiction is self-identified.

Racial and ethnic differences in the home food environment explain disparities in dietary practices of middle school children in Texas.

OBJECTIVE To examine racial and ethnic differences among middle school children in the home food environment (HFE) and the extent to which associations of healthy and unhealthy eating with the HFE differ by race and ethnicity. DESIGN Cross-sectional secondary analyses of baseline data from Coordinated Approach to Child Health Middle School, a school-based intervention targeting obesity and obesogenic behaviors among middle school children in Austin, TX. PARTICIPANTS A total of 2,502 children (mean age, 13.9 years; 58% Hispanic, 28% white, and 14% black). VARIABLES MEASURED Availability and accessibility of healthy foods, and parental support of healthy eating, and family meals. Consumption of both healthy and unhealthy foods was examined. ANALYSIS Differences across racial and ethnic groups in aspects of HFE were estimated using linear regression. Models also examined racial and ethnic differences in consumption of healthy and unhealthy foods. If adjusting for HFE, such differences were accounted for. RESULTS White children had significantly better HFEs than Hispanic and black children with greater availability and accessibility of healthy foods (P < .001). Adjusting for a healthy HFE reduced disparities in consumption of healthy foods but not in consumption of unhealthy foods. CONCLUSIONS AND IMPLICATIONS Improved HFE may increase healthy eating among ethnic minorities but is unlikely to reduce unhealthy eating.

Beliefs and Social Norms About Sildenafil Citrate (Viagra) Misuse and Perceived Consequences Among Houstonian Teenage Males

In the current study, a qualitative approach was used to investigate relevant beliefs and norms associated with sildenafil citrate (Viagra) consumption, initiation, and perceived consequences. Focus groups were conducted with 43 young men aged 18 and 19 years who identified themselves as lifetime sildenafil citrate users. The majority of focus group participants believed that “curiosity” and “peer pressure” contributed to their initial use. Most revealed that they first heard about sildenafil citrate from television advertisements, family members, friends, or sporting events, and they were able to obtain the drug from their friends and family members or they stole it from their father or grandfather. These findings may highlight the relative importance of exposure to prescription drug messages among those to whom the message is not specifically targeted, that is, young men. It is possible that the sildenafil citrate television messages are recalled by not only older male audiences but also by teenagers and younger men, producing similar cognitive processing and curiosity in both age cohorts.