Denisa Mendonça

Biological and socio-cultural determinants of physical activity in adolescents

A atividade fisica e um comportamento importante na promocao de saude e na prevencao de doencas. Para que se desenvolvam programas eficazes no incentivo a pratica de atividade fisica em adolescentes, torna-se necessario que se identifiquem os fatores que a determinam. Este estudo pretende rever alguns dos aspectos do estado atual do conhecimento acerca da influencia de determinantes demografico-biologicos (idade, sexo, estatuto socio-economico) e socio-culturais (familia, pares e professor de educacao fisica) na atividade fisica de adolescentes. Nesta revisao apenas foram incluidos estudos efetuados com amostras superiores a 100 adolescentes com idades entre os 10 e os 18 anos, que tenham adotado delineamentos de pesquisa transversal e que tenham utilizado questionarios. Os principais resultados e conclusoes foram que: a idade parece estar negativamente associada a atividade fisica; o sexo masculino tende a estar mais envolvido nessas atividades; o estatuto socio-economico elevado parece ser um fator protetor do risco de inatividade fisica; a participacao da familia e dos pares em atividades fisicas parece estar positivamente associada as atividades por parte dos adolescentes; o professor de educacao fisica parece nao representar um fator propiciador da atividade fisica.

Bullying in Portuguese Schools.

A modified version of the Olweus school bullying questionnaire was administered to a sample of 4092 pupils, mainly aged 10–12, in ten middle schools, six in the north (Braga) and four in the south of Portugal (Lisbon). We present and discuss the results of this survey on the following topics: frequencies of being bullied and bullying others; types of bullying; places where bullying occurs and children’s opinions about the playground. These variables were analysed in terms of factors such as school grades, under-achievement, social class, gender and school location (north or south of the country). Logistic regression was used to identify risk factors for bullying behaviour. For being bullied, an increased risk was found for male and low social class students. After multivariable adjustment, factors remaining significantly associated with bullying others were gender, school grade, social class and years of under-achievement. The results are compared to the results of other studies in Norway, UK, Italy and Ireland.

Age and sex differences in physical activity of Portuguese adolescents

PURPOSE This study sought to examine sex- and age-associated variations in physical activity (PA) among Portuguese adolescents aged 10-18 yr. METHODS A total of 12,577 males and females at the primary or secondary education level were sampled across four regions of Portugal. PA was assessed by a questionnaire, producing four different indexes: work/school (WSI), sport (SI), leisure time (LI), and total physical activity index (PAI). We examined sex and age differences by using two-way analysis of variance. RESULTS Males had higher mean values of PA than did females. In both sexes, mean values for all four PA indexes increased from ages 10 to 16 yr. After age 16, females decreased their mean values, whereas males continued to increase their values (except for LI). In both sexes, the average annual rate of change for the mean values of all four PA indexes correspond to three sensitive age periods (10-13, 13-16, and 16-18 yr). Until age 16, average mean changes for females ranged from +0.7 to +1.6% per year, except for SI in the youngest group (a modest decrease). For males under 16 yr, the pattern was similar, with increases ranging from 0.4 to 1.9% per year. After age 16, females experienced decreases of 1-2.1% per year for the four PA indexes, whereas males showed an increase for three indexes and an average decrease of 1.3% per year for LI. CONCLUSIONS These results suggest that it is important to consider sex differences in PA levels among Portuguese adolescents. Unlike their male counterparts, Portuguese females may reduce much of their PA during late adolescence.

A 3-year longitudinal analysis of changes in fitness, physical activity, fatness and screen time

Aim:  To analyse whether changes in physical activity index (PAI), screen time (ST: television, computer) and body mass index (BMI) made a contribution to longitudinal changes in fitness of children and adolescents. Additionally, we analysed the interaction between baseline fitness level and changes in fitness.

Spectrum of epilepsy in neurocysticercosis: a long-term follow-up of 143 patients

To characterize the clinical profile and the prognostic factors of the epilepsy due to parenchymal neurocysticercosis (NCC) 143 patients were analysed. Patients (62 men, 81 women) had a mean age at epilepsy onset of 29 years (range 2‐71), mean epilepsy duration of 16 years (range 1‐58) and mean follow‐up of 5.2 years. Seizures were generalised tonic‐clonic (GTC) in 50 patients (35%), simple partial (SP) in 66 (46%) and complex partial (CP) in 27 (19%). Epilepsy began as a single seizure in 73% and as a cluster of seizures or status epilepticus in 27%. Seizures were controlled in 64% of patients. Multivariate analysis revealed that significant prognostic factors associated with seizure control were type of seizures and age at epilepsy onset. Control is more likely in GTC and SP seizures and in patients with a higher age at seizures onset. Our analysis establishes that epilepsy due to NCC is a heterogeneous syndrome concerning age and mode of onset, seizure type, duration of epilepsy and pattern of evolution probably related with different pathogenic mechanisms.

Gender, weight status and socioeconomic differences in psychosocial correlates of physical activity in schoolchildren

OBJECTIVES This study sought to assess differences in attraction to physical activity, perceived physical competence and parental socialization influences across gender, body mass index and socioeconomic status in Portuguese children. DESIGN Cross-sectional study. METHODS 683 children, aged 8-10 years, from elementary schools were participants. Attraction to physical activity, perceived physical competence, parental socialization influences and socioeconomic status were assessed via standardized questionnaires. The prevalence of overweight and obesity was calculated using body mass index, based on the international cut-off points. MANOVA and ANOVA models were conducted. RESULTS Boys reported greater enjoyment of games and sports participation than did girls. Boys and normal-weight children perceived themselves as being more successful and physically competent than did girls and obese children. Normal-weight girls enjoyed participation in vigorous physical activity more than did overweight and obese girls. Obese children felt less accepted by their peers in games and sports than did normal-weight and overweight children. High and medium socioeconomic status children perceived physical activity participation as of greater importance than did low-socioeconomic status children. High-socioeconomic status girls reported greater liking of the exertional aspects of physical activity compared to low socioeconomic status girls. High socioeconomic status children were more likely to perceive their parents as positive role models and perceived that they had greater enjoyment of physical activity than did lower socioeconomic status children. CONCLUSIONS These results suggest that physical activity promotion interventions should focus on girls, obese children and lower socioeconomic status children as these individuals tend to have lower levels of attraction to physical activity, lower perceived physical competence and less parent physical activity support, which puts them at greater risk of being physically inactive.

Strategies to work with HLA data in human populations for histocompatibility, clinical transplantation, epidemiology and population genetics: HLA‐NET methodological recommendations

HLA‐NET (a European COST Action) aims at networking researchers working in bone marrow transplantation, epidemiology and population genetics to improve the molecular characterization of the HLA genetic diversity of human populations, with an expected strong impact on both public health and fundamental research. Such improvements involve finding consensual strategies to characterize human populations and samples and report HLA molecular typings and ambiguities; proposing user‐friendly access to databases and computer tools and defining minimal requirements related to ethical aspects. The overall outcome is the provision of population genetic characterizations and comparisons in a standard way by all interested laboratories. This article reports the recommendations of four working groups (WG1‐4) of the HLA‐NET network at the mid‐term of its activities. WG1 (Population definitions and sampling strategies for population genetics’ analyses) recommends avoiding outdated racial classifications and population names (e.g. ‘Caucasian’) and using instead geographic and/or cultural (e.g. linguistic) criteria to describe human populations (e.g. ‘pan‐European’). A standard ‘HLA‐NET POPULATION DATA QUESTIONNAIRE’ has been finalized and is available for the whole HLA community. WG2 (HLA typing standards for population genetics analyses) recommends retaining maximal information when reporting HLA typing results. Rather than using the National Marrow Donor Program coding system, all ambiguities should be provided by listing all allele pairs required to explain each genotype, according to the formats proposed in ‘HLA‐NET GUIDELINES FOR REPORTING HLA TYPINGS’. The group also suggests taking into account a preliminary list of alleles defined by polymorphisms outside the peptide‐binding sites that may affect population genetic statistics because of significant frequencies. WG3 (Bioinformatic strategies for HLA population data storage and analysis) recommends the use of programs capable of dealing with ambiguous data, such as the ‘gene[rate]’ computer tools to estimate frequencies, test for Hardy–Weinberg equilibrium and selective neutrality on data containing any number and kind of ambiguities. WG4 (Ethical issues) proposes to adopt thorough general principles for any HLA population study to ensure that it conforms to (inter)national legislation or recommendations/guidelines. All HLA‐NET guidelines and tools are available through its website http://hla‐net.eu.

BDNF and CGRP interaction: implications in migraine susceptibility.

Objectives: Migraine pathophysiology involves several pathways. Our aims were to explore a possible role of the brain-derived neurotrophic factor gene (BDNF) in migraine susceptibility; to study, for the first time, the calcitonin gene-related peptide gene (CGRP); and a possible interaction between the two. Methods: Using a case-control approach, four tagging single nucleotide polymorphisms (SNPs) (rs7124442, rs6265, rs11030107, and rs2049046) of BDNF and one tagging SNP—rs1553005—of CGRP were analyzed in 188 cases and 287 controls. A multivariable logistic regression was performed, adjusting for gender. Allelic and haplotypic frequencies were estimated. Interaction was assessed by a stepwise multivariable-logistic regression and confirmed by a multifactor dimensionality reduction analysis. Results: No significant main effects were found; however, a significant interaction was found between BDNF and CGRP, showing an increased risk for the AT-genotype of rs2049046 and the GC-genotype of rs1553005 (odds ratio = 1.88, 95% confidence interval: 1.20–2.93) for migraineurs. Conclusion: Our data support the hypothesis of an interaction between BDNF and CGRP in migraine susceptibility that should be further explored.

The Involvement of Girls and Boys with Bullying: An Analysis of Gender Differences

This exploratory and cross-sectional study aimed to identify the prevalence of bullying in a group of students and analyze the data regarding the gender of those involved in the violence. A questionnaire adapted from Olweus was applied in seven elementary education schools in Portugal. The sample consisted of 387 students between 7 and 14 years old. Data are presented in terms of descriptive statistics and differences between proportions were analyzed using chi-square tests. The gender analysis of victimization and aggression shows that boys and girls are both victims and aggressors, and there are significant differences in involvement in bullying between genders and the roles played. Boys are victims more often when considering different types of bullying, although significant differences were only found for physical aggression. Strategies that include gender roles are a priority for prevention and careful attention to this phenomenon in the school context. The questions addressed contribute to a broader understanding of the phenomenon, emphasizing the differential participation of boys and girls in bullying.

Correlates of physical activity in Portuguese adolescents from 10 to 18 years.

This study examined the association between demographic [age, sex, socioeconomic status (SES)] and socio‐cultural [father, mother, sibling physical activity (PA); peers and physical education teacher influences] correlates and low, moderate and high levels of PA among Portuguese adolescents aged 10–18 years. A total of 3352 males and females attending basic and secondary schools, their parents and siblings were sampled across four regions of Portugal. PA was assessed with a psychometrically validated questionnaire. Multinomial logistic regression was used. Age was positively related with moderate and high PA. Boys and adolescents of high SES were more likely to participate in moderate and high PA. Adolescents were more likely to participate in high PA when theirs mother and sibling(s) also participated. Peers had a positive influence on participation in moderate and high PA, while physical education teachers did not have an influence. The results indicated that demographic and socio‐cultural correlates – in particular age, sex, SES, mother and sibling PA, and peer influence – were significantly associated with adolescent PA. These results also suggested that interventions should focus on girls and low SES adolescents who face higher risk of inactivity.