The Oporto mixed-longitudinal growth, health and performance study. Design, methods and baseline results.

BACKGROUND: Studies concerning child and adolescent growth, development, performance and health aimed at the multiple interactions amongst this complex set of variables are not common in the Portuguese speaking countries. AIM: The aim of this paper is to address the key ideas, methodology and design of the Oporto Growth, Health and Performance Study (OGHPS). SUBJECTS AND METHODS: The OGHPS is a multidisciplinary mixed-longitudinal study whose main purpose is to examine the multiple interactions among biological, environmental and lifestyle indicators that affect growth, development, health and performance of Portuguese adolescents aged 10-18 years old. RESULTS: This study briefly presents baseline results for growth, physical fitness and lifestyle behaviours for those participating in the cross-sectional sample (n ≈ 8000). Approximately 30% were over-fat or obese. On average, boys were more physically fit and active than girls. Few adolescents meet the guidelines for sleep duration (≈10%) and eating habits (16.2-24.8%), while 76-85% meet the recommended levels of moderate-to-vigorous physical activity. CONCLUSIONS: The OGHPS has an innovative approach due to its mixed-longitudinal design and the broad array of variables. Furthermore, subsequent analyses of the longitudinal data will enable a detailed exploration of important factors affecting the growth trajectories of health and performance variables and will also help to identify some of the most opportune times for interventions in terms of health behaviours.

Secular trends in physical fitness of Mozambican school-aged children and adolescents.

OBJECTIVE: This study presents information about secular trends in physical fitness (PF) levels among Mozambican youth. METHODS: The sample comprises 3,851 subjects (1,791 boys; 2,060 girls) aged 8-15 years who were evaluated at three time points (1992, 1999, 2012). PF tests included handgrip strength, 10 m × 5 m shuttle-run, sit-and-reach, and 1-mile run/walk. Biological maturity was assessed by sexual characteristics, and percentage body fat was predicted using triceps and subscapular skinfolds. ANCOVA (controlling for age, maturity status, and percentage body fat) was used to compare mean differences in PF tests among the three time points, by sex. RESULTS: Children in 1992 were more flexible than those from 2012; boys handgrip strength increased from 1992 to 2012, while girls decreased their handgrip strength; youth in 1992 were faster and more agile than their 2012 peers; and a decrease was observed in cardiorespiratory fitness between 1992 and 1999 and between 1992 and 2012 for both sexes. CONCLUSIONS: A negative secular trend among Mozambican children's PF was observed over the last two decades, suggesting that socio-political, educational, and economical changes occurring during this period had a relevant effect on their PF. This negative trend suggests that development of intervention programs/strategies to improve PF among youth is warranted.

Multi-level modelling of physical activity in nuclear families.

BACKGROUND: Few studies focus on the different dyadic relations among family members to study physical activity (PA) levels. AIM: The aim was to investigate predictors and sources of variance of PA levels in nuclear families using multi-level modelling. SUBJECTS AND METHODS: The sample consisted of 2661 Portuguese four-member nuclear families (10 644 subjects). PA was measured using a questionnaire and socioeconomic status (SES) was assessed by parental occupation. Height and weight were measured in children, while parents self-reported their values. RESULTS: The results showed that intra-generational similarities were higher than inter-generational, with correlation values of 0.26 and 0.10, respectively. SES was unrelated to any family members' PA level. Being male (ß = 0.26, t = 21.77), being older (ß = -0.36, t = -4.73) and greater BMI for mothers (ß = 0.02, t = 2.55) had effects on individuals' PA. CONCLUSION: These results suggest a strong dyadic resemblance in PA, showed different effects of gender, age and BMI on individuals' PA and demonstrated that multi-level modelling is a useful strategy to study PA in families.

Physical activity, fitness and the metabolic syndrome in rural youths from Mozambique.

BACKGROUND: Except for North America and Europe, few studies have reported the association among physical activity (PA), cardiorespiratory fitness (CRF) and metabolic syndrome (MetS) in youths, especially for rural African youth. AIM: The aims of this study were to determine the prevalence of PA levels, CRF, MetS and its indicators, and examine the association between these variables in a school-aged sample of youth from rural Mozambique. SUBJECTS AND METHODS: The sample included 209 children and adolescents aged 7-15 years old from Calanga, a rural community in Mozambique. PA was estimated with a culturally-specific questionnaire. CRF was determined by 1-mile run test. Indicators of the MetS included fasting glucose, triglycerides, total cholesterol, blood pressure and body mass index. A continuous metabolic risk score was computed. RESULTS: Results showed high levels of PA and CRF and a low prevalence of MetS ( < 2%) among children and adolescents from Calanga. However, there was a moderately high prevalence of elevated blood pressure (81.8%) and triglycerides (18.7%), respectively. There were no significant associations between PA, CRF and MetS. CONCLUSION: Youths from Calanga are physically active and possess high CRF and their lifestyle may be a protective effect against MetS.

Deslocamento ativo em adolescentes: prevalência e preditores associados ao trajeto casa-escola / Active commuting among adolescents: prevalence and associated predictors at the home-school route

O objetivo do presente estudo é descrever a prevalência de deslocamento ativo entre adolescentes brasileiros no trajeto casa-escola considerando as unidades federativas e regiões do país, e verificar os preditores associados a esse comportamento. A amostra foi composta por 99.967 adolescentes (ambos os sexos; média de idade 14,24 anos) que participaram da Pesquisa Nacional de Saúde do Escolar em 2015. Para o estudo, foram consideradas informações relativas ao deslocamento ativo no percurso casa-escola (frequência e duração), aspecto socioeconômico e percepção de segurança no trajeto para a escola, sendo obtidas através de questionário. A análise estatística foi realizada por meio da regressão logística binária. Foi observado que 44,4% dos jovens realizam o deslocamento ativo (ir e voltar da escola através do uso de bicicleta/caminhada, pelo menos cinco dias na semana), sendo que a região Sudeste apresenta a maior porcentagem de adolescentes que aderem à tal prática (46,4%). Ser do sexo masculino (OR = 1,19), mais "novo" (OR = 0,89) e despender mais tempo por semana em deslocamento ativo (OR = 1,01) aumentam as chances de o adolescente realizar o deslocamento ativo em seu trajeto para a escola; enquanto que possuir carro em casa (OR = 0,72) e perceber o trajeto para a escola como inseguro (OR = 0,66) reduzem as chances de adoção a tal comportamento. Osresul-tados reforçam a característica multifatorial do deslocamento ativo, e a necessidade de intervenções centradas no sujeito e no ambiente

The purpose of this study is to describe the prevalence of active commuting among Brazilian adolescents in their route home-school by federal units and country regions, and to determine the predictors related to it. Sample comprised 99,967 adolescents (both sexes, mean age 14.24 years) that had taken part in the Bra-zilian National Adolescent School-based Health Survey in 2015. For the present study, it was considered information related to active commuting home-school (frequency and duration), socioeconomic status, and security perception at home-school route, which were obtained through questionnaire. Statistical analysis was performed by logistic regression. It was observed that 44.4% of adolescents reported to use the active commuting (go to and from school using bicycle or walking for, at least, five days a week), and the Southwest region showed the highest prevalence of adolescents who use the active commuting (46.4%). Boys (OR = 1.19), younger adolescents (OR = 0.89), and those who spent more weekly time in active commuting (OR = 1.01) are more prone to be adopt the active commuting in their route to and from school; on the other hand, having a car at home (OR = 0.72) and perceive the route to/from school as insecure (OR = 0.66) decrease their chances to adopt this behaviour. Results highlight that active commuting is a multifactorial trait, and the relevance to develop intervention strategies that should take into account both, subjects and the environment

Physical activity, TV viewing, and human development index in Brazilian adolescents: Results from the National School Health Survey

Abstract Aim: This study aimed to examine the association between physical activity (PA) indicators and TV viewing as a function of the Human Development Index (HDI). Method: This cross-sectional study was based on data from the National School Health Survey, which was composed of 102,072 students (14.28±1.03; 51.3% girls). Total PA, active commuting to school (ACS) and TV viewing were assessed by questionnaires and classified through a gradual scale ranging from "F" (low) to "A+" (high). The correlation between total PA, ACS, TV viewing and HDI was verified by Spearman's Correlation and presented in rs. Results: HDI was positively associated with total PA [girls: rs = 0.572 (p < 0.001); boys: rs = 0.843 (p < 0.001)] and ACS [girls: rs = 0.433 (p < 0.001); boys: rs = 0.554 (p < 0.001)]; while a negative correlation was found between HDI and TV viewing [girls: rs = -0.330 (p < 0.001); boys: rs = -0.348 (p < 0.001)]. Conclusions: Brazilian adolescents from states with higher HDI were more active and spent more time watching TV than their counterparts from states with lower HDI.

Who are the Brazilian adolescents most actives during commuting to school? a population-based study

Abstract Aims: 1) to identify the prevalence of active commuting to school (ACS) among Brazilian regions; and 2) to determine associated factors related to ACS in this population. Methods: Cross-sectional study comprising 16,493 adolescents (mean age 14.09±2.12 years). The data comes from the National School Health Survey (2015), and the information was collected by a self-reported questionnaire. Logistic regression models were performed to identify correlates of ACS. Results: Adolescents who live in the Southeast are more prone to have ACS compared to those who live in other regions. Do not have motor vehicles been positively associated with ACS [girls: 2.04 (1.72;2.42); boys 1.85(1.63;2.10)]. Those whom self-reported white was less prone to have ACS compared to their peers from other ethnicities. Those enrolled in private schools [girls: 0.43(0.34;0.54); boys (0.45(0.39;0.53)] and schools setting in rural area [girls: 0.38(0.25;0.57); boys: 0.51(0.37;71)] are less prone to show ACS. In addition, adolescents who accumulated less active time during physical education classes [girls: 0.80(0.66;0.97)] and extracurricular shifts [boys: 0.69(0.60;0.80)] were less prone to have an ACS, compared to their most active peers. Lastly, girls who spent ≤ 2 hours presented fewer odds to have an ACS [0.75(0.63;0.90)]. Conclusions: ACS was most prevalent among those who live in the Southeast region and seems to be negativity associated with the socioeconomic level. Moreover, less active adolescents during both school and leisure time may be more prone to have passive travel go/from school.

Birth weight, physical growth and body composition in children: A longitudinal study / Peso ao nascer, crescimento físico e composição corporal de crianças: um estudo longitudinal

ABSTRACT Objective To describe children's physical growth (body mass and height) velocity and body composition (fat percentage and Fat Free Mass); to investigate the magnitude of interindividual differences according to age, gender and birth weight categories, as well as to examine the differences in the average trajectories of children with Low Birth Weight and Normal Weight according to international references. Methods The sample consisted of 534 children (279 boys and 255 girls, 7 to 10 years old) evaluated in the first year of study and followed for 3 years with overlap between the ages of 7 and 9 years. Physical growth and body composition measurements included: height, body mass, fat percentage (%Fat) and Fat Free Mass. Multilevel Modelling was used. Results Birth weight was not associated with physical growth and body composition markers at 7 years old or with the velocity of their changes (p>0.05). There were significant interindividual differences in the trajectories of physical growth (height and body mass; p<0.001) and body composition (%Fat and Fat Free Mass; p<0.001). In plotting on international percentile charts, the trajectories of growth and body composition were within expected values for age and gender, regardless of birth weight. Conclusion There are significant differences in the dynamics of stature growth, body mass and Fat Free Mass, and Low Birth Weight has no influence on this trajectory. In addition, values are within the expected range for age and sex.

RESUMO Objetivo Este artigo teve por objetivo descrever a velocidade do crescimento físico (massa corporal e estatura) e a composição corporal (percentual de gordura e massa isenta de gordura) de crianças; investigar a magnitude das diferenças interindividuais em função da idade, gênero e categoria do peso ao nascer; e examinar a diferenciação das trajetórias médias das crianças com Baixo Peso ao Nascer e com Peso Adequado ao Nascer, relativamente às referências internacionais. Métodos A amostra foi composta por 534 crianças (279 meninos e 255 meninas, na faixa etária entre 7 e 10 anos de idade), avaliadas no primeiro ano de estudo e seguidas por três anos, com sobreposição de idade entre 7 e 9 anos. Foram medidas a estatura e a massa corporal, e estimados o percentual de gordura (%Gord) e a Massa Isenta de Gordura. As análises foram realizadas com a Modelagem Multinível. Resultados O peso ao nascer não apresentou associação com as variáveis de crescimento físico e composição corporal aos 7 anos de idade, bem como com seus incrementos dos 7 aos 10 anos (p>0,05). Há diferenças interindividuais significativas nas trajetórias de crescimento físico (estatura, massa corporal; p<0,001) e composição corporal (%Gord e Massa Isenta de Gordura; p<0,001). Na plotagem realizada em cartas percentílicas internacionais, independentemente do peso ao nascer, as trajetórias do crescimento e composição corporal encontram-se dentro dos valores esperados para idade e gênero. Conclusão O estudo concluiu que existem diferenças significativas no dinamismo do crescimento estatural, massa corporal e Massa Isenta de Gordura, e o Baixo Peso ao Nascer não exerce nenhuma influência nessa trajetória. Ademais, os seus valores estão dentro do expectável para idade e gênero.

Physical activity, BMI and metabolic risk in Portuguese adolescents / Atividade física, IMC e risco metabólico em adolescentes portugueses

Abstract It has been reported, in the last decades, a significant decrease in physical activity (PA) levels, with a consequent increase in obesity and metabolic risk factors among youth. The aims of this study were to describe PA levels, the prevalence of overweight/ obesity and metabolic risk factors, and to examine the association between PA and body mass index (BMI) with metabolic risk among Portuguese youth. The sample comprises 212 Portuguese adolescents (12-16 years old). Height and weight were measured. PA was estimated with the Bouchard questionnaire (3 days recall), as well as with the use of a pedometer (used for 5 consecutive days). Metabolic risk factors comprised fasting glucose, triglycerides, HDL-cholesterol, systolic blood pressure and waist circumference. Subjects were classified as normal weight, overweight or obese according to BMI; the maturational status was indirectly estimated with the maturity offset procedure. A continuous metabolic risk score was computed (zMR) and PA values were divided into tertiles. Quisquare test, t-test and ANOVA were used in statistical analyses. SPSS 18.0 and WinPepi softwares were used and p<0.05. A moderate to high prevalence of overweight/obesity and HDL-cholesterol was found, as well as a high prevalence of high blood pressure and low to moderate PA levels among Portuguese youth. The relationship between BMI and zMR showed that obese adolescents have higher zMR when compared to normal weight or overweight adolescents. This finding suggests that increased levels of PA and reduction in the prevalence of overweight/obesity may have a positive role against the development of metabolic risk factors.

Resumo Tem-se verificado, nas últimas décadas, uma redução substancial nos níveis de atividade física (AF), com o consequente aumento da prevalência de sobrepeso/obesidade e fatores de risco metabólico entre jovens. O presente estudo teve por objetivos identificar os níveis de AF e as prevalências de sobrepeso/obesidade e risco metabólico, e associar o índice ponderal com os níveis de AF e risco metabólico em jovens portugueses. A amostra foi composta por 212 jovens portugueses (12-16 anos). Estatura e peso foram mensurados. AF foi estimada a partir do recordatório de 3 dias de Bouchard e pelo uso do pedômetro (durante 5 dias). Os indicadores de risco metabólico considerados foram: glicose, triglicerídeos, HDL-colesterol, tensão arterial sistólica e perímetro da cintura. Os sujeitos foram classificados consoante índice ponderal a partir do índice de massa corporal, enquanto que o estatuto maturacional foi estimado a partir do offset maturacional. Score contínuo de risco metabólico (zRM) foi calculado, e a AF foi dividida em tercis. Os testes estatísticos utilizados foram o Qui-quadrado, teste t independente e ANOVA, as análises foram conduzidas no SPSS 18.0 e WinPepi (p<0,05). Observou-se uma prevalência moderada a elevada de sobrepeso/obesidade e HDL-colesterol, uma elevada prevalência de risco para tensão arterial, e níveis de AF baixos a moderados entre jovens portugueses. A relação entre índice ponderal e zRM mostrou que adolescentes obesos apresentam maior zRM comparativamente aos adolescentes normoponderais ou com sobrepeso. Incrementos nos níveis de AF e redução da prevalência de sobrepeso/obesidade podem ter um papel relevante na redução de fatores de risco metabólico.

Associação entre atividade física, aptidão cardiorrespiratória e síndrome metabólica em crianças e adolescentes: estado da arte / Association between physical activity, cardiorespiratory fitness and metabolic syndrome in youth: the state of the art

O presente estudo teve como objetivo sintetizar os principais resultados da associação entre atividade física (AF) e/ou aptidão cardiorrespiratória com a síndrome metabólica (SM) em crianças e adolescentes. Efetuou-se uma busca on-line nas bases de dados Pubmed, Scopus, Web of Science e Lilacs para selecionar artigos que investigaram a relação entre AF e/ou aptidão cardiorrespiratória e SM em crianças e adolescentes, publicados entre os anos de 2004 e 2009. Foram localizados 20 estudos que atenderam aos critérios adotados, dos quais 19 compuseram a amostra. Uma associação negativa entre AF e/ou aptidão cardiorrespiratória e SM foi observada. Os valores da associação apresentaram oscilação, a qual pode ser relacionada aos métodos utilizados para recolha da informação, à inexistência de critérios unânimes para determinação da SM em crianças e adolescentes, ao tamanho e características amostrais. Os resultados sugerem que incrementos dos níveis de AF (odds ratio de 1,3 a 5,16, e b = -0.02 a -0.21) e aptidão cardiorrespiratória (odds ratio de 2,42 a 13,0, e b = -0.09 a -0,44) em jovens se apresentam como estratégias para prevenção de fatores de risco metabólico. Não obstante a representatividade dos dados, há a necessidade de estudos posteriores em populações de nações em transição, de forma a possibilitar uma melhor compreensão desta relação.

The present study aimed to summarize the main results of the association between physical activity (PA) and cardiorespiratory fitness with metabolic syndrome (MS) in children and adolescents. An on-line search was made on Pubmed, Scopus, Web of Science and Lilacs databases for published studies concerning the relationship between PA and/or cardiorespiratory fitness with MS in children and adolescents. Published studies covered a period from 2004 to 2009. Twenty studies were found showing according to inclusion criteria, but only 19 were included in the sample. In general a negative association between PA and cadiorespiratory fitness with MS was observed. The association was not equal across studies; a wide variability between them was found, and design of each study, sample size and characteristics, as well as the lack of a universal definition of MS in youth may account for such discrepancies. Improvement on PA levels (odds ratio between 1,3 to 5,16, and b = -0.02 to -0.21) and on cardiorespiratory fitness (odds ratio between 2,42 to 13,0, and b = -0.09 to -0,44) in youth is a potential strategy to overcoming the metabolic risk factors in this population. Notwithstanding data representativeness, it is necessary further studies in developing countries population for a better understanding for this relationship.