ABSTRACT
Abstract: The objective of this study was to verify whether residential density and connectivity between streets are mediators on the association between perceived environmental factors and active commuting to school (ACS) in Brazilian adolescents. This is a cross-sectional study with a random sample of 1,130 adolescents (52.7% girls) aged between 14 to 20 years, from Porto Alegre, Rio Grande do Sul State, Brazil. Adolescents' self-reported their usual mode of commuting to and from school using a questionnaire and the perceived environmental attributes by Neighborhood Environment Walkability Scale for Youth (NEWS-Y). Residential density and connectivity between streets were measured by gographic information systems (GIS), within 1km road network buffers around the participant's residential address. Regression models were fitted according to mediation analyses procedures. The results showed that residential density is a mediator on the association between ACS and perceived environmental factors, including land-use mix diversity (IE = 0.114; 95%CI: 0.130, 0.311; 32% mediation), neighborhood recreation facilities (IE = 0.064; 95%CI: 0.034, 0.105; 15% mediation), and access to services (IE = 0.045; 95%CI: 0.006, 0.104; 14% mediation). Connectivity between streets did not correlate with ACS, thus it was not tested in the mediation model. In conclusion, residential density is a mediator on the relationship between perceived environmental factors and ACS.
Resumo: O estudo teve como objetivo verificar se a densidade residencial e a conectividade entre ruas são mediadores da associação entre fatores ambientais percebidos e deslocamento ativo casa-escola (DAE) em adolescentes brasileiros. Foi um estudo transversal com uma amostra randomizada de 1.130 adolescentes (52,7% do sexo feminino) entre 14 e 20 anos de idade, de Porto Alegre, Rio Grande do Sul, Brasil. Os adolescentes informaram seu modo de deslocamento casa-escola (ida e volta) através de um questionário, além dos atributos ambientais percebidos, de acordo com a Neighborhood Environment Walkability Scale for Youth (NEWS-Y). A densidade residencial e a conectividade entre ruas foram medidas por sistemas de informação geográfica (SIG), dentro de um raio de 1km da rede viária em torno do endereço residencial do participante. Foram ajustados modelos de regressão de acordo com os procedimentos para análises de mediação. Os resultados mostraram que a densidade residencial é um mediador da associação entre os fatores ambientais percebidos e o DAE, inclusive a diversidade do uso do solo (EI = 0,114; IC95%: 0,130, 0,311; 32% de mediação), infraestrutura para atividades de lazer na vizinhança (EI = 0,064; IC95%: 0,034, 0,105; 15% de mediação) e acesso a serviços (EI = 0,045; IC95%: 0,006, 0,104; 14% de mediação). A conectividade entre ruas não mostrou correlação com DAE, portanto não foi testado no modelo de mediação. Conclui-se que a densidade residencial é um mediador da relação entre fatores ambientais percebidos e DAE.
Resumen: El objetivo fue verificar si la densidad poblacional y la conectividad entre calles son mediadores en la asociación entre los factores ambientales percibidos y el desplazamiento activo a la escuela (DAE) en adolescentes brasileños. Se trata de un estudio transversal, con una muestra aleatoria de 1.130 adolescentes (52,7% chicas), con una edad comprendida entre los 14 y los 20 años de edad, de Porto Alegre, Río Grande do Sul, Brasil. Los adolescentes autoinformaron su modo habitual de desplazamiento "a" y "desde" la escuela, usando un cuestionario y las características ambientales percibidas mediante el Neighborhood Environment Walkability Scale for Youth (NEWS-Y). La densidad poblacional y conectividad entre las calles se midieron mediante los sistemas de información geográfica (GIS), dentro de una red vial delimitada por un radio de 1km alrededor de la dirección residencial del participante. Los modelos de regresión se ajustaron según los procedimientos para el análisis de mediación. Los resultados mostraron que la densidad poblacional es un a mediador en la asociación entre los factores ambientales percibidos y la DAE, incluyendo el uso del suelo para diversos fines (EI = 0,114; IC95%: 0,130, 0,311; 32% mediación), instalaciones recreativas en el barrio (EI = 0,064; IC95%: 0,034, 0,105; 15% mediación), y acceso a los servicios (EI = 0,045; IC95%: 0,006, 0,104; 14% mediación). Conectividad entre calles que no mostraron correlación con DAE, por consiguiente, no fue probado en el modelo de mediación. En conclusión, la densidad poblacional es un mediador en la relación entre los factores ambientales percibidos con DAE.
Subject(s)
Humans , Male , Female , Adolescent , Adult , Young Adult , Transportation , Walking , Schools , Brazil , Residence Characteristics , Cross-Sectional Studies , Environment DesignABSTRACT
Background: A high percentage of Chilean university students are inactive. Aim: To determine differences in physical activity (PA) levels and energy expenditure in a group of university students according to their length of stay in the university. Material and Methods: We studied 56 students aged 22 ± 2 years (29 women). They wore a triaxial accelerometer during seven days, determining steps/day, steps/min, sedentary time and PA levels. Participants also answered a PA questionnaire. Their weight and height were measured. They were divided in two groups according to the time spent at university (1-2 years and 3-5 years). Results: No significant differences in energy expenditure were observed between both groups of students. The number of steps/day and steps/ min was significantly higher in the group with 3 to 5 years in the university than their counterparts with 1-2 years. Conclusions: As the university years increase, there is a tendency to increase the time spent walking (18.3%) but without an increase in the moderate-vigorous PA.