Margarida Gaspar de Matos

Socioeconomic Inequality in Exposure to Bullying During Adolescence: A Comparative, Cross-Sectional, Multilevel Study in 35 Countries

OBJECTIVES We examined the socioeconomic distribution of adolescent exposure to bullying internationally and documented the contribution of the macroeconomic environment. METHODS We used an international survey of 162,305 students aged 11, 13, and 15 years from nationally representative samples of 5998 schools in 35 countries in Europe and North America for the 2001-2002 school year. The survey used standardized measures of exposure to bullying and socioeconomic affluence. RESULTS Adolescents from families of low affluence reported higher prevalence of being victims of bullying (odds ratio [OR] = 1.13; 95% confidence interval [CI] = 1.10, 1.16). International differences in prevalence of exposure to bullying were not associated with the economic level of the country (as measured by gross national income) or the school, but wide disparities in affluence at a school and large economic inequality (as measured by the Gini coefficient) at the national level were associated with an increased prevalence of exposure to bullying. CONCLUSIONS There is socioeconomic inequality in exposure to bullying among adolescents, leaving children of greater socioeconomic disadvantage at higher risk of victimization. Adolescents who attend schools and live in countries where socioeconomic differences are larger are at higher risk of being bullied.

Exercise autonomous motivation predicts 3-yr weight loss in women.

PURPOSE This study evaluated exercise-related predictors of successful long-term weight control in women by analyzing the extent to which sustained exercise participation and self-determination theory (SDT)-based exercise motivation variables mediated the impact of a behavioral weight control intervention on 3-yr weight change. METHODS Longitudinal randomized controlled trial consisting of a 1-yr SDT-based intervention and a 2-yr follow-up with 221 female participants (means ± SD: age = 37.6 ± 7 yr, body mass index = 31.6 ± 4.1 kg·m(-2)). The tested model incorporated experimentally manipulated perceived need support, motivational regulations, and 2-yr exercise adherence as mediators of the interventions impact on 3-yr weight change. Paths were tested using partial least squares analysis. Where there were significant intervening paths, tests of mediation were conducted. RESULTS Treatment had significant effects on 1- and 2-yr autonomous regulations, 2-yr physical activity, and 3-yr weight change, fully mediated by the tested paths (effect ratio = 0.10-0.61). Moderate and vigorous exercise at 2 yr had a significant effect (P < 0.001) on weight loss success at 3 yr and partially mediated the effect of treatment on weight change. The 2-yr autonomous regulation effects on follow-up weight change were only partially mediated by physical activity (effect ratio = 0.42). CONCLUSIONS This application of SDT to physical activity and weight management showed that not all types of motivation predict long-term behavioral outcomes and that sustained moderate and vigorous exercise mediated long-term weight change. It provides strong evidence for a link between experimentally increased autonomous motivation and exercise and long-term weight loss maintenance. Results highlight the importance of interventions targeting the internalization of exercise behavioral regulation and making exercise and physical activity positive and meaningful experiences rather than simply focusing on immediate behavior change in overweight/obese women.

A randomized controlled trial to evaluate self-determination theory for exercise adherence and weight control: rationale and intervention description

BackgroundResearch on the motivational model proposed by Self-Determination Theory (SDT) provides theoretically sound insights into reasons why people adopt and maintain exercise and other health behaviors, and allows for a meaningful analysis of the motivational processes involved in behavioral self-regulation. Although obesity is notoriously difficult to reverse and its recidivism is high, adopting and maintaining a physically active lifestyle is arguably the most effective strategy to counteract it in the long-term. The purposes of this study are twofold: i) to describe a 3-year randomized controlled trial (RCT) aimed at testing a novel obesity treatment program based on SDT, and ii) to present the rationale behind SDTs utility in facilitating and explaining health behavior change, especially physical activity/exercise, during obesity treatment.MethodsStudy design, recruitment, inclusion criteria, measurements, and a detailed description of the intervention (general format, goals for the participants, intervention curriculum, and main SDT strategies) are presented. The intervention consists of a 1-year group behavioral program for overweight and moderately obese women, aged 25 to 50 (and pre-menopausal), recruited from the community at large through media advertisement. Participants in the intervention group meet weekly or bi-weekly with a multidisciplinary intervention team (30 2 h sessions in total), and go through a program covering most topics considered critical for successful weight control. These topics and especially their delivery were adapted to comply with SDT and Motivational Interviewing guidelines. Comparison group receive a general health education curriculum. After the program, all subjects are follow-up for a period of 2 years.DiscussionResults from this RCT will contribute to a better understanding of how motivational characteristics, particularly those related to physical activity/exercise behavioral self-regulation, influence treatment success, while exploring the utility of Self-Determination Theory for promoting health behavior change in the context of obesity.Trial RegistrationClinical Trials Gov. Identifier NCT00513084

Negative School Perceptions and Involvement in School Bullying: A Universal Relationship across 40 Countries.

Cross-national analyses explore the consistency of the relationship between negative school experiences and involvement in bullying across 40 European and North American countries, using the 2006 (40 countries n = 197,502) and 2002 (12 countries, n = 57,007) WHO-HBSC surveys. Measures include two Cumulative Negative School Perception (CNSP) scales, one based on 6 mandatory items (2006) and another including an additional 11 items (2002). Outcome measures included bullying perpetration, victimization and involvement as both bully and victim. Logistic regression analyses suggested that children with only 2-3 negative school perceptions, experience twice the relative odds of being involved in bullying as compared with children with no negative school perceptions. Odds Ratios (p < 0.001) increase in a graded fashion according to the CNSP, from about 2.2 to over 8.0. Similar consistent effects are found across gender and almost all countries. Further research should focus on the mechanisms and social context of these relationships.

Validity of BMI based on self-reported weight and height in adolescents

Aim:  To assess in a subset of a nationally representative sample of Portuguese adolescents, the validity of Body Mass Index (BMI) based on self‐reported weight and height.

Are overweight and obese adolescents different from their peers

OBJECTIVE To identify psychosocial and lifestyle indicators including alcohol consumption, that may distinguish overweight and obese adolescents from their peers, and align them with other adolescents with chronic conditions. METHODS The sample included 6 131 6th, 8th, and 10th grade public school Portuguese students, aged 11-16 years, who participated in the Health Behavior in School-Aged Children (HBSC)/WHO survey of adolescent health. Body mass index (BMI) was based on self reported weight and height. Separate analyses of psychosocial and behavioral variables were conducted by gender, age group, and BMI, using Chi square, and ANOVA. RESULTS Obese and overweight teens when compared with non-overweight teens, were more likely to report a negative attitude towards their appearance; to believe that others made negative comments about them; had a lower level of life satisfaction; had more difficulty in making new friends, and were more likely to describe themselves as unhappy. Moreover, obese teens were significantly more likely than their non-obese peers to describe themselves as having health problems, to report drinking alcohol daily, as well as having been drunk more than 10 times. CONCLUSIONS The present study provides further evidence regarding the association between overweight and obesity in adolescence, and body image dissatisfaction, poorer self-assessed health status, potential social isolation, decreased life satisfaction, and problematic alcohol consumption patterns. Overweight and obese adolescents should, where possible, be reached with appropriate interventions addressing the broad spectrum of their psychological needs, enhancing their skill development for behavioral change, and providing support for dealing with potentially harmful behaviors.

Trends and socioeconomic correlates of adolescent physical fighting in 30 countries

BACKGROUND AND OBJECTIVES: No recent international studies provide evidence about its prevalence, trends, or social determinants of physical fighting in adolescents. We studied cross-national epidemiologic trends over time in the occurrence of frequent physical fighting, demographic variations in reported trends, and national wealth and income inequality as correlates. METHODS: Cross-sectional surveys were administered in school settings in 2002, 2006, and 2010. Participants (N = 493874) included eligible and consenting students aged 11, 13, and 15 years in sampled schools from 30 mainly European and North American countries. Individual measures included engagement in frequent physical fighting, age, gender, participation in multiple risk behaviors, victimization by bullying, and family affluence. Contextual measures included national income inequality, absolute wealth and homicide rates. Temporal measure was survey cycle (year). RESULTS: Frequent physical fighting declined over time in 19 (63%) of 30 countries (from descriptive then multiple Poisson regression analyses). Contextual measures of absolute wealth (relative risk 0.96, 95% confidence interval 0.93–0.99 per 1 SD increase in gross domestic product per capita) but not income inequality (relative risk 1.01, 95% confidence interval 0.98–1.05 per 1 SD increase) related to lower levels of engagement in fighting. Other risk factors identified were male gender, younger age (11 years), multiple risk behaviors, victimization by bullying, and national homicide rates. CONCLUSIONS: Between 2002 and 2010, adolescent physical fighting declined in most countries. Specific groups of adolescents require targeted violence reduction programs. Possible determinants responsible for the observed declines are discussed.

Peer victimization and subjective health among students reporting disability or chronic illness in 11 Western countries

BACKGROUND To compare the strength of the association between peer victimization at school and subjective health according to the disability or chronic illness (D/CI) status of students across countries. METHODS This study used data from 55 030 students aged 11, 13 and 15 years from 11 countries participating in the 2005-06 Health Behaviour in School-aged Children survey. Self-completed questionnaires were administered in classrooms. Multivariate models of logistic regression (controlled for confounding factors and countries) were used to investigate differences in the association between peer victimization and poor subjective health according to the D/CI status. RESULTS Overall, 13.5% of the students reported having been bullied at least two or three times a month. The percentage of victims was significantly higher among those reporting D/CI than among others in all countries studied. Victims of bullying were more likely to report poor self-rated health, low life satisfaction and multiple health complaints. However, there were no differences in the associations between peer victimization and subjective health indicators according to the D/CI status. CONCLUSIONS In all countries studied, students reporting D/CI were more likely to report being victims of bullying. Victims of bullying reported more negative subjective health outcomes regardless of their D/CI status. Although inclusive education is currently a major topic of educational policies in most countries, additional efforts should be made to improve the quality of the integration of students with D/CI.

Evolutionary domestication in Drosophila subobscura.

The domestication of plants and animals is historically one of the most important topics in evolutionary biology. The evolutionary genetic changes arising from human cultivation are complex because of the effects of such varied processes as continuing natural selection, artificial selection, deliberate inbreeding, genetic drift and hybridization of different lineages. Despite the interest of domestication as an evolutionary process, few studies of multicellular sexual species have approached this topic using well‐replicated experiments. Here we present a comprehensive study in which replicated evolutionary trajectories from several Drosophila subobscura populations provide a detailed view of the evolutionary dynamics of domestication in an outbreeding animal species. Our results show a clear evolutionary response in fecundity traits, but no clear pattern for adult starvation resistance and juvenile traits such as development time and viability. These results supply new perspectives on the confounding of adaptation with other evolutionary mechanisms in the process of domestication.

Variation in the rate of convergent evolution: adaptation to a laboratory environment in Drosophila subobscura

Adaptation to novel environments is a central issue in evolutionary biology. One important question is the prevalence of convergence when different populations adapt to the same or similar environments. We investigated this by comparing two studies, 6 years apart, of laboratory adaptation of populations of Drosophila subobscura founded from the same natural location. In both studies several life‐history traits were periodically assayed for the first 14 generations of laboratory adaptation, as well as later generations, and compared with established, laboratory, control populations. The results indicated: (1) a process of convergence for all traits; (2) differences between the two studies in the pattern and rate of convergence; (3) dependence of the evolutionary rates on initial differentiation. The differences between studies might be the result of the differences in the founder populations and/or changes in the lab environment. In either case, the results suggest that microevolution is highly sensitive to genetic and environmental conditions.