Measurement of physical activity and sedentary behavior in national health surveys, South America.

Objectives: To characterize how physical activity and sedentary behavior have been measured in national health surveys in South American countries. Methods: An extensive search was made for national health surveys from all 12 South American countries through health websites, national statistical offices, and contact with researchers and policy-makers. The following eligibility criteria were used to select surveys: conducted in a South American country; used a nationally representative sample ≥ 18 years; coordinated by the public, private or mixed private-public sector; and assessed physical activity and/or sedentary behavior. Data were extracted on general information about the surveys, specific details about the physical activity and sedentary behavior assessment, and additional questions related to activity behavior. Results: In total, 36 surveys were included, two of which were multicountry surveys; all surveys assessed physical activity and 27 assessed sedentary behavior. Most surveys (23/36; 64%) were based on previously validated international questionnaires, but 13 (57%) of these deviated from the reference tools, introducing changes and adaptations. Sedentary behavior was assessed mostly through questions on screen time and/or daily sitting time in the same physical activity questionnaires. No survey used device-based measures to generate data on these behaviors. Conclusions: Differences between instruments used and modifications limit the comparability of data across countries. This highlights the importance of standardizing assessment within South America for physical activity and sedentary behavior sections in national surveys, with the broader aim of contributing to establishing a standardized strategy for the surveillance of physical activity and sedentary behavior in South America.

Measurement of physical activity and sedentary behavior in national health surveys, South America

[ABSTRACT]. Objectives. To characterize how physical activity and sedentary behavior have been measured in national health surveys in South American countries. Methods. An extensive search was made for national health surveys from all 12 South American countries through health websites, national statistical offices, and contact with researchers and policy-makers. The following eligibility criteria were used to select surveys: conducted in a South American country; used a nationally representative sample ≥ 18 years; coordinated by the public, private or mixed private–public sector; and assessed physical activity and/or sedentary behavior. Data were extracted on general information about the surveys, specific details about the physical activity and sedentary behavior assessment, and additional questions related to activity behavior. Results. In total, 36 surveys were included, two of which were multicountry surveys; all surveys assessed physical activity and 27 assessed sedentary behavior. Most surveys (23/36; 64%) were based on previously validated international questionnaires, but 13 (57%) of these deviated from the reference tools, introducing changes and adaptations. Sedentary behavior was assessed mostly through questions on screen time and/or daily sitting time in the same physical activity questionnaires. No survey used device-based measures to generate data on these behaviors. Conclusions. Differences between instruments used and modifications limit the comparability of data across countries. This highlights the importance of standardizing assessment within South America for physical activity and sedentary behavior sections in national surveys, with the broader aim of contributing to establishing a standardized strategy for the surveillance of physical activity and sedentary behavior in South America.

[RESUMEN]. Objetivos. Describir cómo se han medido la actividad física y el sedentarismo en las encuestas nacionales de salud en los países de América del Sur. Métodos. Se llevó a cabo una extensa búsqueda de encuestas nacionales de salud de los doce países sudamericanos en sitios web de salud, oficinas nacionales de estadística y mediante el contacto con investigadores y responsables de formular políticas. Para escoger las encuestas se emplearon los siguientes criterios de selección: realizada en un país sudamericano; muestra representativa a nivel nacional de ≥ 18 años; coordinada por el sector público, el sector privado o mixto público-privado; y evaluación de la actividad física o el sedentarismo. Se extrajeron datos como información general de las encuestas, detalles específicos de la evaluación de la actividad física y el sedentarismo, y otras preguntas relacionadas con la actividad física. Resultados. En total, se incluyeron 36 encuestas, dos de las cuales se realizaron en varios países. Todas las encuestas evaluaron la actividad física; 27, el sedentarismo. La mayoría de las encuestas (23/36; 64%) se basaron en cuestionarios internacionales anteriormente validados, de los cuales 13 (57%) se desviaron de las herramientas de referencia al tener cambios y adaptaciones. El sedentarismo se evaluó principalmente en los mismos cuestionarios de actividad física mediante preguntas sobre el tiempo invertido delante de pantallas o el tiempo diario sentado. Ninguna encuesta aplicó medidas basadas en dispositivos para obtener datos sobre estos comportamientos. Conclusiones. Las diferencias entre los instrumentos empleados y las modificaciones limitan la comparabilidad de los datos en todos los países. Esto pone de relieve la importancia de estandarizar la evaluación en América del Sur de las secciones dedicadas a la actividad física y al sedentarismo en las encuestas nacionales, con el objetivo general de contribuir a la creación de una estrategia estandarizada para la vigilancia de la actividad física y el sedentarismo en América del Sur.

[RESUMO]. Objetivos. Caracterizar como a atividade física e o comportamento sedentário têm sido medidos em pesquisas nacionais de saúde em países sul-americanos. Métodos. Foi realizada uma busca extensa de pesquisas nacionais de saúde de todos os 12 países sul-americanos em sites de saúde e órgãos nacionais de estatística, e pelo contato com pesquisadores e formuladores de políticas. Foram usados os seguintes critérios de elegibilidade para selecionar as pesquisas: conduzida em um país sul-americano; que tenha usado uma amostra nacionalmente representativa ≥ 18 anos; coordenada pelo setor público, privado ou público-privado; e que tenha avaliado a atividade física e/ou o comportamento sedentário. Os dados extraídos eram sobre informações gerais das pesquisas, detalhes específicos sobre a avaliação da atividade física e do comportamento sedentário e questões adicionais relacionadas ao comportamento na atividade. Resultados. Ao todo, 36 pesquisas foram incluídas, duas das quais foram conduzidas em vários países. Todas as pesquisas avaliaram a atividade física e 27 avaliaram o comportamento sedentário. A maioria das pesquisas (23/36; 64%) baseou-se em questionários internacionais previamente validados e 13 (57%) delas se desviaram das ferramentas de referência, introduzindo mudanças e adaptações. O comportamento sedentário foi avaliado principalmente por meio de perguntas sobre tempo de tela e/ou tempo diário sentado nos mesmos questionários sobre atividade física. Nenhuma pesquisa utilizou medições realizadas por dispositivos para gerar dados sobre esses comportamentos. Conclusões. As diferenças entre os instrumentos usados e as modificações limitam a comparabilidade dos dados entre os países, o que destaca a importância de padronizar a avaliação na América do Sul para as seções de atividade física e comportamento sedentário em pesquisas nacionais, com o objetivo mais amplo de contribuir para o estabelecimento de uma estratégia padronizada para a vigilância da atividade física e do comportamento sedentário na América do Sul.

Measurement of physical activity and sedentary behavior in national health surveys, South America / Medición de la actividad física y del sedentarismo en encuestas nacionales de salud en América del Sur / Mensuração de atividade física e comportamento sedentário em pesquisas nacionais de saúde, América do Sul

ABSTRACT Objectives. To characterize how physical activity and sedentary behavior have been measured in national health surveys in South American countries. Methods. An extensive search was made for national health surveys from all 12 South American countries through health websites, national statistical offices, and contact with researchers and policy-makers. The following eligibility criteria were used to select surveys: conducted in a South American country; used a nationally representative sample ≥ 18 years; coordinated by the public, private or mixed private-public sector; and assessed physical activity and/or sedentary behavior. Data were extracted on general information about the surveys, specific details about the physical activity and sedentary behavior assessment, and additional questions related to activity behavior. Results. In total, 36 surveys were included, two of which were multicountry surveys; all surveys assessed physical activity and 27 assessed sedentary behavior. Most surveys (23/36; 64%) were based on previously validated international questionnaires, but 13 (57%) of these deviated from the reference tools, introducing changes and adaptations. Sedentary behavior was assessed mostly through questions on screen time and/or daily sitting time in the same physical activity questionnaires. No survey used device-based measures to generate data on these behaviors. Conclusions. Differences between instruments used and modifications limit the comparability of data across countries. This highlights the importance of standardizing assessment within South America for physical activity and sedentary behavior sections in national surveys, with the broader aim of contributing to establishing a standardized strategy for the surveillance of physical activity and sedentary behavior in South America.

RESUMEN Objetivos. Describir cómo se han medido la actividad física y el sedentarismo en las encuestas nacionales de salud en los países de América del Sur. Métodos. Se llevó a cabo una extensa búsqueda de encuestas nacionales de salud de los doce países sudamericanos en sitios web de salud, oficinas nacionales de estadística y mediante el contacto con investigadores y responsables de formular políticas. Para escoger las encuestas se emplearon los siguientes criterios de selección: realizada en un país sudamericano; muestra representativa a nivel nacional de ≥ 18 años; coordinada por el sector público, el sector privado o mixto público-privado; y evaluación de la actividad física o el sedentarismo. Se extrajeron datos como información general de las encuestas, detalles específicos de la evaluación de la actividad física y el sedentarismo, y otras preguntas relacionadas con la actividad física. Resultados. En total, se incluyeron 36 encuestas, dos de las cuales se realizaron en varios países. Todas las encuestas evaluaron la actividad física; 27, el sedentarismo. La mayoría de las encuestas (23/36; 64%) se basaron en cuestionarios internacionales anteriormente validados, de los cuales 13 (57%) se desviaron de las herramientas de referencia al tener cambios y adaptaciones. El sedentarismo se evaluó principalmente en los mismos cuestionarios de actividad física mediante preguntas sobre el tiempo invertido delante de pantallas o el tiempo diario sentado. Ninguna encuesta aplicó medidas basadas en dispositivos para obtener datos sobre estos comportamientos. Conclusiones. Las diferencias entre los instrumentos empleados y las modificaciones limitan la comparabilidad de los datos en todos los países. Esto pone de relieve la importancia de estandarizar la evaluación en América del Sur de las secciones dedicadas a la actividad física y al sedentarismo en las encuestas nacionales, con el objetivo general de contribuir a la creación de una estrategia estandarizada para la vigilancia de la actividad física y el sedentarismo en América del Sur.

RESUMO Objetivos. Caracterizar como a atividade física e o comportamento sedentário têm sido medidos em pesquisas nacionais de saúde em países sul-americanos. Métodos. Foi realizada uma busca extensa de pesquisas nacionais de saúde de todos os 12 países sul-americanos em sites de saúde e órgãos nacionais de estatística, e pelo contato com pesquisadores e formuladores de políticas. Foram usados os seguintes critérios de elegibilidade para selecionar as pesquisas: conduzida em um país sul-americano; que tenha usado uma amostra nacionalmente representativa ≥ 18 anos; coordenada pelo setor público, privado ou público-privado; e que tenha avaliado a atividade física e/ou o comportamento sedentário. Os dados extraídos eram sobre informações gerais das pesquisas, detalhes específicos sobre a avaliação da atividade física e do comportamento sedentário e questões adicionais relacionadas ao comportamento na atividade. Resultados. Ao todo, 36 pesquisas foram incluídas, duas das quais foram conduzidas em vários países. Todas as pesquisas avaliaram a atividade física e 27 avaliaram o comportamento sedentário. A maioria das pesquisas (23/36; 64%) baseou-se em questionários internacionais previamente validados e 13 (57%) delas se desviaram das ferramentas de referência, introduzindo mudanças e adaptações. O comportamento sedentário foi avaliado principalmente por meio de perguntas sobre tempo de tela e/ou tempo diário sentado nos mesmos questionários sobre atividade física. Nenhuma pesquisa utilizou medições realizadas por dispositivos para gerar dados sobre esses comportamentos. Conclusões. As diferenças entre os instrumentos usados e as modificações limitam a comparabilidade dos dados entre os países, o que destaca a importância de padronizar a avaliação na América do Sul para as seções de atividade física e comportamento sedentário em pesquisas nacionais, com o objetivo mais amplo de contribuir para o estabelecimento de uma estratégia padronizada para a vigilância da atividade física e do comportamento sedentário na América do Sul.

How may the reduction of some cardiovascular diseases affect Brazilian population's life expectancy? / Como a redução de algumas doenças cardiovasculares pode afetar a expectativa de vida da população brasileira? / ¿Cómo puede afectar la reducción de algunas enfermedades cardiovasculares la esperanza de vida de la población brasileña?

This study aimed to analyze the impact of cardiovascular diseases (CVDs) on life expectancy (LE) in the Brazilian population; and to identify how the hypothetical reduction in mortality from 5 to 30%, as well as the hypothetical scenario with no deaths (i.e., elimination) of these diseases would affect LE. This is a simulation study using national cross-sectional data. To identify the impact of CVDs on LE, we used multiple decrement life table models, considering hypothetical CVDs reductions in mortality from 5 to 30% and their elimination. The estimated overall potential gains in LE [years (%)] from the elimination of ischemic disease, hypertensive disease, and cerebrovascular disease were 1.44y (2%) and 1.31y (1.7%), 0.51y (0.7%) and 0.75y (1%), and 1.28y (1.8%) and 1.62y (2.1%), for males and females, respectively. The largest gains in LE were observed among those who live in Brazil's Northeast region. For the overall population, the estimated gains in LE linked to a 5% reduction in CVD mortality for males and females were 0.07y (0.1%) and 0.06y (0.08%) for ischemic disease, 0.02y (0.03%) and 0.04y (0.05%) for hypertensive disease, and 0.06y (0.08%) and 0.07y (0.09%) for cerebrovascular disease. A hypothetical decrease of 30% in mortality by CVDs would lead to gains in LE, for males and females, of 0.41y (0.6%) and 0.37y (0.5%) for ischemic disease, 0.15y (0.2%) and 0.22y (0.3%) for hypertensive disease, and 0.36y (0.5%) and 0.45y (0.6%) for cerebrovascular disease. Thus, investment towards improving CVDs, including CVD prevention efforts, would increase LE in Brazil, especially in less developed regions.

O presente estudo objetiva analisar o impacto das doenças cardiovasculares (DCV) na expectativa de vida (EV) da população brasileira e identificar como a EV seria afetada pela redução hipotética de 5% a 30% e pela eliminação da mortalidade por essas doenças. Trata-se de um estudo de simulação que utiliza dados transversais a nível nacional. A análise foi realizada por meio do modelo de tábuas de vida de múltiplo decremento, considerando reduções na mortalidade por DCV de 5% a 30%, assim como a sua eliminação. Os ganhos potenciais estimados na EV, em anos e porcentagem, por meio da eliminação das doenças isquêmica, hipertensiva e cerebrovascular foram de, respectivamente, para homens e mulheres, 1,44 (2%) e 1,31 (1,7%), 0,51 (0,7%) e 0,75 (1%), 1,28 (1,8%) e 1,62 (2,1%). Os maiores ganhos ocorrem entre os residentes na região Nordeste. Além disso, para a população em geral, os ganhos estimados em EV a partir de uma redução de 5% na mortalidade por DCV, em homens e mulheres, foram de 0,07 (0,1%) e 0,06 (0,08%), para doença isquêmica, 0,02 (0,03%) e 0,04 (0,05%), para doença hipertensiva, e 0,06 (0,08%) e 0,07 (0,09%), para doença cerebrovascular. Já uma redução hipotética de 30% na mortalidade por DCV foi acompanhada de ganhos na EV, para homens e mulheres, de 0,41 (0,6%) e 0,37 (0,5%), para doença isquêmica, 0,15 (0,2%) e 0,22 (0,3%), para doença hipertensiva, e 0,36 (0,5%) e 0,45 (0,6%), para doença cerebrovascular. Assim, mais investimentos e esforços orientados para a prevenção de DCV aumentariam a EV no Brasil, principalmente nas regiões menos desenvolvidas.

Los objetivos de este estudio fueron analizar el impacto de las enfermedades cardiovasculares (ECV) en la esperanza de vida (EV) de la población brasileña e identificar cuánto afectarían a la EV una hipotética reducción del 5 al 30% o la eliminación de la mortalidad por estas enfermedades. Este es un estudio de simulación que utiliza datos transversales nacionales. El análisis de datos se hizo utilizando modelos de tablas de vida de múltiples decrementos, considerando reducciones en la mortalidad por ECV del 5% al 30% así como su eliminación. Las ganancias potenciales estimadas para la EV [años (%)] vinculadas a la eliminación de la enfermedad isquémica, enfermedad hipertensiva, y la enfermedad cerebrovascular fueron 1,44 (2%) y 1,31 (1,7%), 0,51 (0,7%) y 0,75 (1%), y 1,28 (1,8%) y 1,62 (2,1%), para varones y mujeres, respectivamente. Las mayores ganancias en la EV fueron observadas en la población de la región noreste de Brasil. Las ganancias estimadas en EV ligadas a una reducción del 5% en la mortalidad por ECV en hombres y mujeres fueron 0,07 (0,1%) y 0,06 (0,08%) para enfermedad isquémica, 0,02 (0,03%) y 0,04 (0,05%) para enfermedad hipertensiva, y 0,06 (0,08%) y 0,07 (0,09%) para enfermedad cerebrovascular. Una disminución hipotética del 30% en la mortalidad por ECV se acompañaría de ganancias en EV, para hombres y mujeres, de 0,41 (0,6%) y 0,37 (0,5%) para enfermedad isquémica, 0,15 (0,2%) y 0,22 (0,3%) para enfermedad hipertensiva, y 0,36 (0,5%) y 0,45 (0,6%) para enfermedad cerebrovascular. Esfuerzos orientados a la prevención de las ECV aumentarían la EV en Brasil, especialmente en las regiones menos desarrolladas.

Macroeconomic, demographic and human developmental correlates of physical activity and sitting time among South American adults.

BACKGROUND: Our aim was to investigate the association of macroeconomic, human development, and demographic factors with different domains of physical activity and sitting time among South American adults. METHODS: We used data from nationally representative samples in Argentina (n = 26,932), Brazil (n = 52,490), Chile (n = 3866), Colombia (n = 14,208), Ecuador (n = 19,883), Peru (n = 8820), and Uruguay (n = 2403). Our outcomes included leisure time (≥150 min/week), transport (≥10 min/week), occupational (≥10 min/week), and total (≥150 min/week) physical activity, as well as sitting time (≥4 h/day), which were collected through self-reported questionnaires. As exposures, gross domestic product, total population, population density, and human development index indicators from the most updated national census of each country were used. Age and education were used as covariates. Multilevel logistic regressions with harmonized random effect meta-analyses were conducted, comparing highest vs. lowest (reference) tertiles. RESULTS: Higher odds for transport physical activity were observed among the highest tertiles of total population (ORmen: 1.41; 95% CI: 1.23-1.62), ORwomen: 1.51; 95% CI:1.32-1.73), population density (ORmen: 1.36; 95% CI: 1.18-1.57, ORwomen: 1.49; 95% CI: 1.30-1.70), and gross domestic product (ORmen: 1.16; 95% CI: 1.00-1.35, ORwomen: 1.39; 95% CI: 1.20-1.61). For leisure physical activity, women living in departments with higher human development index presented 18% higher odds for being active, and for total physical activity a similar estimate in both sexes was observed among those who live in more populated areas. No consistent associations were found for occupational physical activity and sitting time. CONCLUSION: Macroeconomic, demographic and human development indicators are associated with different domains of physical activity in the South American context, which can in turn guide policies to promote physical activity in the region.

Why are children different in their moderate-to-vigorous physical activity levels? A multilevel analysis / Por que as crianças são diferentes em seus níveis de atividade física de intensidade moderada a vigorosa? Uma análise multinível

Abstract Objective: Children's differences in moderate-to-vigorous physical activity levels are not at random. This study investigates the relevance of individual- and school-level characteristics in explaining these differences. Methods: In total, 307 children (154 girls) aged 5-10 years, from 19 Portuguese schools, were sampled. Height and weight were measured, and body mass index was calculated. Time spent in moderate-to-vigorous physical activity was measured by accelerometry. Gross motor coordination was assessed with the KörperkoordinationsTest für Kinder battery and socio-economic status was obtained via the school social support system. School characteristics were obtained with an objective school audit. A multilevel analysis was used as implemented in Stata 15. Results: Schools explained 18.2% of the total variance in moderate-to-vigorous physical activity, with the remainder being ascribed to children's distinct characteristics. Boys were more active (β = 29.59 ± 11.52, p < 0.05), and having higher gross motor coordination levels (β = 0.11 ± 0.04, p < 0.05) was positively associated with daily moderate-to-vigorous physical activity, whereas being older (β = −5.00 ± 1.57, p < 0.05) and having higher socio-economic status (β = −7.89 ± 3.12, p < 0.05) were negatively related with moderate-to-vigorous physical activity. From the school-level correlates, only playground dimension was significantly associated with moderate-to-vigorous physical activity levels. Children from schools with medium (40 m2 to 69 m2) and large playground dimensions (≥70 m2) were less active than children with smaller playground dimensions (10 m2 to 39 m2). Conclusions: Variation in school children's moderate-to-vigorous physical activity is mostly explained by their individual characteristics; school characteristics also play a role but to a smaller degree. Future intervention programs to change this behavior should be more personalized, emphasizing mostly individual-level characteristics.

Resumo Objetivo As diferenças entre crianças na atividade física moderada a vigorosa não são aleatórias. Este estudo investiga a relevância das características em níveis individuais e escolares para explicar essas diferenças. Métodos Foram amostradas 307 crianças (154 meninas) entre 5 e 10 anos, de 19 escolas portuguesas. A estatura e o peso foram medidos e o índice de massa corporal foi calculado. O tempo gasto em atividade física moderada a vigorosa foi medido por acelerometria. A coordenação motora grossa foi avaliada com a bateria do Körperkoordinationstest für Kinder e o status socioeconômico foi obtido através do sistema de apoio social da escola. As características da escola foram obtidas através de uma auditoria escolar objetiva. Uma análise multinível foi utilizada como implantada no Stata 15. Resultados As escolas explicaram 18,2% da variância total da atividade física moderada a vigorosa, com o restante atribuído às diferentes características das crianças. Os meninos foram mais ativos (β = 29,59 ± 11,52, p < 0,05) e o fato de ter níveis mais altos de coordenação motora grossa (β = 0,11 ± 0,04, p < 0,05) foi positivamente associado com a atividade física moderada a vigorosa diária. Os mais velhos (β = -5,00 ± 1,57, p < 0,05) e com maior status socioeconômico (β = -7,89 ± 3,12, p < 0,05) foram negativamente relacionados com a atividade física moderada a vigorosa. Com base nos correlatos a nível escolar, apenas a dimensão da área recreativa foi significativamente associada aos níveis de atividade física moderada a vigorosa. As crianças das escolas com área recreativa média (40 m2 a 69 m2) e grande (≥ 70 m2) foram menos ativas do que as crianças com áreas recreativas com menores dimensões (10 m2 a 39 m2). Conclusões A variação na atividade física moderada a vigorosa de escolares é explicada principalmente por suas características individuais; as características da escola também desempenham um papel, mas em menor grau. Futuros programas de intervenção para mudar esse comportamento devem ser mais personalizados, enfatizar principalmente as características em nível individual.

Why are children different in their moderate-to-vigorous physical activity levels? A multilevel analysis.

OBJECTIVE: Children's differences in moderate-to-vigorous physical activity levels are not at random. This study investigates the relevance of individual- and school-level characteristics in explaining these differences. METHODS: In total, 307 children (154 girls) aged 5-10 years, from 19 Portuguese schools, were sampled. Height and weight were measured, and body mass index was calculated. Time spent in moderate-to-vigorous physical activity was measured by accelerometry. Gross motor coordination was assessed with the KörperkoordinationsTest für Kinder battery and socio-economic status was obtained via the school social support system. School characteristics were obtained with an objective school audit. A multilevel analysis was used as implemented in Stata 15. RESULTS: Schools explained 18.2% of the total variance in moderate-to-vigorous physical activity, with the remainder being ascribed to children's distinct characteristics. Boys were more active (ß=29.59±11.52, p<0.05), and having higher gross motor coordination levels (ß=0.11±0.04, p<0.05) was positively associated with daily moderate-to-vigorous physical activity, whereas being older (ß=-5.00±1.57, p<0.05) and having higher socio-economic status (ß=-7.89±3.12, p<0.05) were negatively related with moderate-to-vigorous physical activity. From the school-level correlates, only playground dimension was significantly associated with moderate-to-vigorous physical activity levels. Children from schools with medium (40m2 to 69m2) and large playground dimensions (≥70m2) were less active than children with smaller playground dimensions (10m2 to 39m2). CONCLUSIONS: Variation in school children's moderate-to-vigorous physical activity is mostly explained by their individual characteristics; school characteristics also play a role but to a smaller degree. Future intervention programs to change this behavior should be more personalized, emphasizing mostly individual-level characteristics.

Endocrine parameters in association with bone mineral accrual in young female vocational ballet dancers.

Less is known on bone mass gains in dancers involved in vocational dance training. The present study found that, as young vocational dancers progress on their professional training, their bone health remains consistently lower compared to non-exercising controls. Endocrine mechanisms do not seem to explain these findings. PURPOSE: Little is known on bone mass development in dancers involved in vocational training. The aim of the present study was to model bone mineral content (BMC) accruals and to determine whether circulating levels of oestrogens, growth hormone (GH), and insulin-like growth factor I (IGF-1) explain differences in bone mass gains between vocational dance students and matched controls. METHODS: The total of 67 vocational female dancers (VFDs) and 68 aged-matched controls (12.1 ± 1.9 years and 12.7 ± 2.0 years at baseline, respectively) were followed for two consecutive years (34 VFD and 31 controls remained in the study for the full duration). BMC was evaluated annually at impact [femoral neck (FN); lumbar spine (LS)] and non-impact sites (forearm) using DXA. Anthropometry, age at menarche (questionnaire), and hormone serum concentrations (immunoradiometric assays) were also assessed for the same period. RESULTS: VFD demonstrated consistently reduced body weight (p < 0.001) and BMC at all three anatomical sites (p < 0.001) compared to controls throughout the study period. Menarche, body weight, GH, and IGF-1 were significantly associated with bone mass changes over time (p < 0.05) but did not explain group differences in BMC gains at impact sites (p > 0.05). However, body weight did explain the differences between groups in terms of BMC gains at the forearm (non-impact site). CONCLUSION: Two consecutive years of vocational dance training revealed that young female dancers demonstrate consistently lower bone mass compared to controls at both impact and non-impact sites. The studied endocrine parameters do not seem to explain group differences in terms of bone mass gains at impact sites.

How Consistent are Genetic Factors in Explaining Leisure-Time Physical Activity and Sport Participation? The Portuguese Healthy Families Study.

This study investigates how consistent genetic factors are, as measured by heritability estimates (h2), in the leisure-time physical activity index (LTPAI) and sport participation index (SPI) from early (10-14 yrs) to late adolescence (15-19 yrs). The sample comprises 12,385 subjects from 3,378 Portuguese nuclear families. Height and weight were measured and body mass index (BMI) was calculated, and the LTPAI and SPI were estimated by questionnaire. Socioeconomic status (SES) was assessed by parental occupation. Analyses were done using S.A.G.E. software. Our results showed that h2 estimates for the LTPAI and SPI in the two age groups (10-14 yrs and 15-19 yrs) were stable: for the LTPAI, h2 = 0.297 and 0.322, respectively; and for the SPI, h2 = 0.413 and 0.428, respectively. Sibling correlations and environmental correlations are higher in the younger age group for both the LTPAI and the SPI. Spousal correlations are higher in the younger age group for the LTPAI and lower for the SPI than the older group. Parent-offspring correlations are similar in both age groups for the LTPAI and SPI. In conclusion, the influence of genetic factors on physical activity and sport participation remains stable across age in adolescence. However, variation in sibling correlations - in particular, environmental correlations - was observed. These findings suggest that shared/non-shared environmental factors express different degrees of importance across age. Future intervention programs aiming to promote change in behaviors need to consider these results to bring about positive changes in physical activity and sport participation behaviors within the family setting.

Association between body mass index and individual characteristics and the school context: a multilevel study with Portuguese children / Relação entre o índice de massa corporal e as características individuais e do contexto escolar: um estudo multinível com crianças portuguesas

Abstract Objective The aim of this study was to examine the association between individual and school context characteristics with the body mass index of Portuguese children. Methods The sample comprised 1641 children (847 boys) aged 6-10 years from the North and Central regions of Portugal. Regarding the individual characteristics, age, gender, city of residence, levels of physical activity, and physical fitness were assessed. Concerning the school context characteristics, the surrounding environment, school size, presence of recreational characteristics and space, and presence of a sports court and of physical education classes were considered. Children's body mass index was the dependent variable. The multilevel analysis was carried out in HLM 7.0 software. Results The predictors of the child and the school context explained, respectively, 97.3% and 2.7% of the total body mass index variance. Regarding the individual characteristics, older children, boys, and those who had lower performance at the 1-mile run/walk, curl-up, push-up, and higher performance in trunk lift tests showed higher BMI. Further, urban schools with higher recreational spaces were positively associated with children's body mass index. Conclusion School context variables have a reduced effect on body mass index variation compared to the children's biological and behavioral characteristics. The authors therefore encourage strategies that aim to increasing children's physical fitness levels to help prevent excess weight.

Resumo Objetivo Examinar a associação de características individuais e do contexto escolar no índice de massa corporal de crianças portuguesas. Método A amostra compreendeu 1.641 crianças (847 meninos) de 6 a 10 anos. Em relação às características individuais foram utilizadas informações relativas ao sexo, à idade, à residência, à atividade física e à aptidão física. Em termos de contexto escolar, foram considerados o meio ambiente, o tamanho da escola, a presença de recreio, as características e as dimensões do espaço disponível para o recreio, a existência de quadra poliesportiva e de aulas de educação física. O índice de massa corporal [kg/(m2)] foi a variável dependente. A análise multinível foi efetuada no software HLM 7.0. Resultados Os preditores da criança e do contexto escolar explicaram, respectivamente, 97,3% e 2,7% da variância total do índice de massa corporal. Quanto às características individuais, a idade (mais velhos) e o sexo (meninos), bem como o desempenho reduzido nas provas de corrida/marcha da milha, do curl-up, do push-up e valores elevados no trunk lift, estiveram associados ao aumento no índice de massa corporal. Escolas do meio urbano e escolas com maiores espaços para o recreio também estiveram positivamente associadas ao aumento do índice de massa corporal. Conclusões As variáveis do contexto escolar têm um efeito reduzido na variação do índice de massa corporal comparativamente às características biológicas e comportamentais das crianças. Sugere-se a aplicação de programas que visem ao incremento dos níveis de aptidão física das crianças para prevenir o excesso de peso na infância.

Association between body mass index and individual characteristics and the school context: a multilevel study with Portuguese children.

OBJECTIVE: The aim of this study was to examine the association between individual and school context characteristics with the body mass index of Portuguese children. METHODS: The sample comprised 1641 children (847 boys) aged 6-10 years from the North and Central regions of Portugal. Regarding the individual characteristics, age, gender, city of residence, levels of physical activity, and physical fitness were assessed. Concerning the school context characteristics, the surrounding environment, school size, presence of recreational characteristics and space, and presence of a sports court and of physical education classes were considered. Children's body mass index was the dependent variable. The multilevel analysis was carried out in HLM 7.0 software. RESULTS: The predictors of the child and the school context explained, respectively, 97.3% and 2.7% of the total body mass index variance. Regarding the individual characteristics, older children, boys, and those who had lower performance at the 1-mile run/walk, curl-up, push-up, and higher performance in trunk lift tests showed higher BMI. Further, urban schools with higher recreational spaces were positively associated with children's body mass index. CONCLUSION: School context variables have a reduced effect on body mass index variation compared to the children's biological and behavioral characteristics. The authors therefore encourage strategies that aim to increasing children's physical fitness levels to help prevent excess weight.

Genotype by sex and genotype by age interactions with sedentary behavior: the Portuguese Healthy Family Study.

Sedentary behavior (SB) expression and its underlying causal factors have been progressively studied, as it is a major determinant of decreased health quality. In the present study we applied Genotype x Age (GxAge) and Genotype x Sex (GxSex) interaction methods to determine if the phenotypic expression of different SB traits is influenced by an interaction between genetic architecture and both age and sex. A total of 1345 subjects, comprising 249 fathers, 327 mothers, 334 sons and 325 daughters, from 339 families of The Portuguese Healthy Family Study were included in the analysis. SB traits were assessed by means of a 3-d physical activity recall, the Baecke and IPAQ questionnaires. GxAge and GxSex interactions were analyzed using SOLAR 4.0 software. Sedentary behaviour heritability estimates were not always statistically significant (p>0.05) and ranged from 3% to 27%. The GxSex and GxAge interaction models were significantly better than the single polygenic models for TV (min/day), EEsed (kcal/day), personal computer (PC) usage and physical activty (PA) tertiles. The GxAge model is also significantly better than the polygenic model for Sed (min/day). For EEsed, PA tertiles, PC and Sed, the GxAge interaction was significant because the genetic correlation between SB environments was significantly different from 1. Further, PC and Sed variance heterogeneity among distinct ages were observed. The GxSex interaction was significant for EEsed due to genetic variance heterogeneity between genders and for PC due to a genetic correlation less than 1 across both sexes. Our results suggest that SB expression may be influenced by the interactions between genotype with both sex and age. Further, different sedentary behaviors seem to have distinct genetic architectures and are differentially affected by age and sex.

Familial resemblance of physical activity levels in the Portuguese population.

OBJECTIVES: Moderate to high levels of physical activity are related to positive health status. Parents share with their children important cultural aspects and beliefs related to healthy living. However, family studies show contradictory results for familial aggregation of physical activity. The purposes of this study were to assess whether physical activity shows familial aggregation in the Portuguese population and to disentangle the exact pattern of familial resemblance. DESIGN: Cross-sectional family study. METHODS: We sampled 2661 Portuguese nuclear families (10,644 subjects) and assessed their physical activity using the Baecke questionnaire, including components for physical activity work/school, leisure-time activity, sports participation, and a total index of physical activity. Generalized estimating equations were used to compute spousal, parent-offspring and sibling correlations. RESULTS: For leisure-time activity and total index of physical activity, the patterns were characterized with spouse correlations higher than parent-offspring correlations (0.20 vs 0.12, p=0.001 and 0.22 vs 0.12, p=10(-4), respectively) but lower than those in offspring (0.20 vs 0.51, p<10(-4) and 0.22 vs 0.35, p<10(-4), respectively). For sports participation, the spouse correlation was higher than parent-offspring correlations (0.30 vs 0.18, p<10(-4)), but also higher than sibling correlations (0.30 vs 0.22, p<10(-4)). Finally, the physical activity work/school spouse correlation was higher than the sibling correlations (0.22 vs 0.12, p<10(-4)). CONCLUSIONS: The results support the hypothesis of familial aggregation in physical activity. Further, fathers and mothers had a similar influence on their offspring's physical activity levels irrespective of their sex, and equal sibling correlations point toward shared physical activity habits.