Sociodemographic and behavioral factors associated with physical activity in Brazilian adolescents.

Leandro Fornias Machado De Rezende,Catarina Machado Azeredo,Olinda Do Carmo Luiz,Daniela Silva Canella,Renata Bertazzi Levy,Inês Rugani Ribeiro De Castro,Rafael Moreira Claro

doi:10.1186/1471-2458-14-485

Abstract

BackgroundPhysical activity in adolescents is associated with short- and long-term health benefits. Physical activity can occur in various domains and is influenced by a complex network of factors. The aims of this study are 1) to describe the physical activity of Brazilian adolescents in physical education classes, during leisure time, and during active commuting and 2) to investigate the socio-demographic and behavioral factors associated with physical activity.MethodsThe representative sample included 109,104 Brazilian students in the final year of elementary school from 2,842 schools. The weekly frequency and duration of physical activity were assessed. A variety of socio-demographic and behavioral factors were studied. A multiple Poisson regression analysis was used to test for associations between physical activity and the socio-demographic and behavioral variables.ResultsMost of the students (97.0%) engaged in physical activity in at least one of the domains studied, especially physical education at school (81.7%) and leisure time physical activity (67.5%). However, only 29% of the adolescents reached the recommended level of physical activity. Among the adolescents who reached the minimum recommended time for physical activity, the various domains contributed the following proportions to total physical activity: leisure time physical activity (PR 12.5; 95% CI 11.17-13.97), active commuting (PR 1.63; 95% CI 1.59-1.67), and physical education at school (PR 1.36; 95% CI 1.29-1.44). The weekly frequency of all activities was greater among boys than among girls. Moreover, nearly two-thirds (61.8%) of students spent more than two hours per day engaging in sedentary behaviors; the prevalence of sedentary behaviors was similar between boys and girls (59.0 and 64.5%, respectively).Total level of physical activity, leisure time physical activity, and active commuting were associated with higher nutritional scores.ConclusionsPhysical activity is important in any health promotion program. Therefore, it is necessary to invest in policies and interagency initiatives that promote all domains and to ensure that the general population helps determine the scope and design of such policies.

Highlights

Physical activity in adolescents is associated with short- and long-term health benefits
The present study’s aims are as follows: 1) to describe the physical activity of Brazilian adolescents in various domains and 2) to investigate the socio-demographic and behavioral factors associated with physical activity
Study population, sampling, and data collection Data collected for the National Adolescent Schoolbased Health Survey (Pesquisa Nacional de Saúde do Escolar–PeNSE), which was conducted between April and September 2012, were used in the present study

Summary

Introduction

Physical activity in adolescents is associated with short- and long-term health benefits. The benefits offered by moderate-tovigorous physical activity (MVPA) include lower cardiometabolic risk [3,4], less fat mass [3,5], and greater physical fitness (especially cardiorespiratory) [3]. In addition to these immediate results, physical activity in adolescence increases the probability of becoming an active and healthy adult [6] and lowers the risk of future health problems, such as fractures [7] and breast cancer [8]. 80% of the global population is located in low-and middleincome countries, only a small fraction of studies on the determinants of physical inactivity are conducted in these nations [10,11]

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