Ronald J. Iannotti

OBJECTIVE: The high prevalence of adolescent obesity in the United States has been attributed to population changes in physical activity (PA), sedentary behaviors, and dietary behaviors. This study examines 8-year trends in these behaviors in US adolescents ages 11 to 16. METHODS: Nationally representative samples of US students in grades 6 to 10 were recruited during the 2001–2002 (N = 14 607), 2005–2006 (N = 9150), and 2009–2010 (N = 10 848) school years by using multistage stratified designs, with census regions and grades as strata, and school districts as the primary sampling units. African-American and Hispanic students were oversampled to obtain better estimates for those groups. Using the Health Behavior in School-aged Children quadrennial surveys, identical questions assessed BMI, PA, and sedentary and dietary behaviors at each school year. Logistic and linear regression analyses were conducted taking into account the sampling design and controlling for age, gender, race/ethnicity, and family affluence. RESULTS: Across the quadrennial surveys, significant increases were identified in number of days with at least 60 minutes of PA, daily consumption of fruits and vegetables, eating breakfast on weekdays and weekends, and BMI. Television viewing and consumption of sweets and sweetened beverages decreased across this same period. These same patterns were seen in all racial/ethnic groups. CONCLUSIONS: These patterns suggest that public health efforts to improve the obesity-related behaviors of US adolescents may be having some success. However, alternative explanations for the increase in BMI over the same period need to be considered.

Background: Perceived body appearance and body satisfaction are potentially related to weight problems and poor health. The purpose of this study was to examine how gender, and ethnic differences in body satisfaction, perceived body appearance and weight status change by age in a representative sample of U.S. adolescents 11–17 years old. Methods: We used the US Health Behavior in School-Aged Children (HBSC) 2001 survey which assessed perceived body appearance, body satisfaction, self-reported body mass index (BMI) and socio-demographic indicators. The associations between age and perceived appearance, age and body satisfaction, and between z-transformed BMI and body satisfaction were analyzed using separate non-parametric regression models for both genders and the three ethnic groups. Results: Body satisfaction did not vary significantly by age except for an increase with age in the proportion of Non-Hispanic White girls who perceived themselves as too fat. Although boys did not report being too fat unless their BMI was above the age- and gender-specific median, one third of Non-Hispanic White girls felt too fat at or below the age- and gender-specific median. Compared to other ethnicities, African-American students’ perceived appearance was significantly more positive and they were less likely to perceive themselves overweight at higher BMI scores. However, during adolescence, the positive self-reported perceived appearance of African-American boys dropped substantially while it remained relatively stable in African-American girls. Conclusions: There were substantial differences in body satisfaction and perceived appearance across the three largest ethnic groups of school-age children in the U.S. Stability across age indicates that these perceptions are most likely established before the age of 10 and underline the importance of primary schools and parents in prevention. Special attention should be directed to the dramatic loss of positive perceived appearance among African-American boys.

Physical activity as measured by activity counts over short time intervals across a 24 h period are often used to assess circadian variation. We are interested in characterizing circadian patterns in activity among adolescents and examining how these patterns vary by obesity status. New statistical approaches are needed to examine how factors affect different features of the circadian pattern and to make appropriate covariate adjustments when the outcomes are longitudinal count data. We develop a statistical model for longitudinal or repeated activity count data that is used to examine differences in the overall activity level, amplitude (defined as the difference between the lowest and highest activity level over a 24 hour period), and phase shift. Using seven days of continuous activity monitoring, we characterize the circadian patterns and compare them between obese and non-obese adolescent girls. We find a statistically significant phase delay in adolescent girls who were obese compared with their non-obese counterparts. After the appropriate adjustment for measured potential confounders, we did not find differences in mean activity level between the two groups. New statistical methodology was developed to identify a phase delay in obese compared with non-obese adolescents. This new approach for analyzing longitudinal circadian rhythm count data provides a useful statistical technique to add to the repertoire for those analyzing circadian rhythm data.

The purpose of this study was to develop a measure of diabetes-specific parenting goals for parents of children with type 1 diabetes and to examine whether parenting goals predict a change in parenting involvement in disease management. An independent sample of primary caretakers of 87 children aged 10 to 16 years with type 1 diabetes completed the measure of parenting goals (diabetes-specific and general goals); both parent and child completed measures of parent responsibility for diabetes management at baseline and 6 months. Parents ranked diabetes-specific parenting goals as more important than general parenting goals, and rankings were moderately stable over time. Parenting goals were related to parent responsibility for diabetes management. The relative ranking of diabetes-specific parenting goals predicted changes in parent involvement over 6 months, with baseline ranking of goals predicting more parental involvement at follow-up. Parenting goals may play an important role in family management of type 1 diabetes.

Objectives: To examine how adolescent physical activity (PA) and screen-based media sedentary behaviours (SBM) relate to psychological and social health and identify cross-national differences in these relationships. Methods: Associations were examined in five regions using two Health Behaviour in School-Aged Children (HBSC) countries from each. Results: Self-reported psychological and social health indices such as self-image, perceived health status, and Life Satisfaction were positively related to PA in all five regions but, with a few exceptions, negatively related to SBM. Negative health indices such as health complaints and tobacco use were negatively related to PA but, with exceptions, positively related to SBM. Significant regional differences were present. Conclusions: Regional differences in correlates of PA and SBM suggest cultural differences in potential effects of PA and SBM and the need to tailor school and public health efforts to the different meanings of PA and SBM for positive and negative health consequences.

Background:  Physical aggression is an important issue in North American populations. The importance of students’ social environments in the occurrence of physical aggression requires focused study. In this study, reports of physical aggression were examined in relation to social environment factors among national samples of students from Canada and the United States.Methods:  Students in grades 6‐10 from the United States (n = 14,049) and Canada (n = 7058) who had participated in the Health Behaviour in School‐aged Children Survey (HBSC) were studied. Rates of students’ physical aggression were compared between the 2 countries. School, family, socioeconomic, and peer‐related factors were considered as potential risk factors. A simple social environment risk score was developed using the US data and was subsequently tested in the Canadian sample.Results:  Risks for physical aggression were consistently higher among United States versus Canadian students, but the magnitude of these differences was modest. The relative odds of physical aggression increased with reported environmental risk. To illustrate, US boys in grades 6‐8 reporting the highest social environment risk score (5+) experienced a relative odds of physical aggression 4.02 (95% CI 2.7‐5.9) times higher than those reporting the lowest score (adjusted OR for risk scores 0 through 5+ was 1.00, 1.19, 2.10, 2.01, 3.71, and 4.02, respectively, p_trend < .001).Conclusions:  Unexpectedly, rates of physical aggression and associations between social environments and students’ aggression were remarkably similar in Canada and the United States. Family, peer, and school social environments serve as risk or protective factors, with significant cumulative impact on physical aggression in both countries. Given the observed high rates and the many negative effects of aggression on long‐term health, school policies aimed at the reduction of such behavior remain a clear priority.

OBJECTIVE—The purpose of this study is to evaluate two updated measures of diabetes regimen adherence. The Diabetes Self-Management Profile (DSMP) is a widely used, structured interview. Limitations include a substantial interviewer and respondent time burden and the need for well-trained interviewers to use appropriate prompts and score the open-ended responses. The Diabetes Behavior Rating Scale (DBRS) is a self-administered, fixed-choice survey.

The goal of this research was to develop and evaluate measures of adolescent diabetes management self-efficacy and outcome expectations that reflect developmentally relevant, situation-specific challenges to current diabetes regimens. Self-efficacy for diabetes management, expected outcomes of adherence, adherence to the diabetes regimen, and glycemic control were assessed in 168 adolescents (ages10-16 years) with type 1 diabetes. Factor analyses indicated a single scale for self-efficacy and two distinct factors representing positive and negative outcome expectations. Reliability and predictive validity of the new scales were supported. In regression analyses, self-efficacy and the interaction of self-efficacy with expectations of positive outcomes were significantly associated with diabetes self-management adherence and glycemic control in older adolescents. The effect of self-efficacy was greatest when adolescents had stronger beliefs in the beneficial outcomes of adherence. These brief measures can be used to identify youths at risk of poor diabetes self-management. Interventions targeting self-efficacy may lead to improved diabetes self-management.