Search

Background: Sedentary behavior is associated with increased risk of chronic disease and sedentary behavior is increasing among adolescents. Data on changes in sedentary behavior in developing countries are limited., Purpose: To describe 5-year longitudinal changes in nonschool sedentary hours among urban adolescents in Ho Chi Minh City, and to identify correlates with this change., Methods: This is a 5-year longitudinal cohort with systematic random sampling of 759 students from 18 junior high schools. All measures were taken annually between 2004 and 2009. Sedentary behavior was assessed by self-report and accelerometry. Generalized linear latent and mixed models were used to analyze the data in 2011., Results: Between 2004 and 2009, self-reported time spent in nonschool sedentary behavior increased from 498 to 603 minutes/day. In the 5th survey year, boys and girls (aged 16 years) were, respectively, 3.6 times (95% CI=2.3, 6.0) and 3.1 times (95% CI= 1.8, 5.0) more likely to spend ≥2 hours/day on screen time compared with baseline (aged 12 years). Accelerometer data adjusted for wearing time revealed that boys and girls aged 16 years had, respectively, 78 minutes/day (95% CI=48, 104) and 69 minutes/day (95% CI=34, 95) more nonschool sedentary time than those at the first accelerometer assessment (at age 13 years). Girls in the highest socioeconomic quartile spent an additional 90 minutes/day in sedentary behavior compared with girls in the lowest quartile (95% CI=52, 128)., Conclusions: Nonschool sedentary behavior increased among Vietnamese adolescents with age. The largest increase was in recreational screen time (28%), which would be the most obvious target for preventive health strategies., (Copyright © 2013 American Journal of Preventive Medicine. All rights reserved.)

Background: Active commuting (walking or cycling) to/from school is an important part of the overall physical activity levels of children but is on the decline in many countries. Data for adolescents on mode of transportation to and from school are limited for low- and middle-income countries, including Vietnam., Purpose: This paper aims to describe the changes in the prevalence of active commuting to and from school, and to examine prospectively the predictors of active commuting, among adolescents from Ho Chi Minh City (HCMC)., Methods: The data are from a 5-year cohort study from 2004 of a representative sample of 759 adolescents from 18 schools in HCMC. Data were obtained at five annual assessments using validated questionnaires to capture commuting behaviors, socioeconomic and demographic factors, individual and family characteristics, and physical and social environmental factors. Height and weight were measured by trained staff using standardized guidelines. Generalized linear latent and mixed models with a hierarchic approach were used to analyze the data in 2011., Results: The results show a remarkable decrease in the prevalence of active commuting in adolescents from 27.8% in 2004 to 19.6% in 2009. Male students, from the least-wealthy families, living in suburban areas, close to school, studying at schools in less-wealthy districts, were more likely to actively commute., Conclusions: In the context of an epidemic of childhood and adolescent obesity in urban Vietnam, the decline in active commuting over the 5 years of this study highlights the need for development of urban physical environments favorable for active commuting and education campaigns to promote active commuting in adolescents., (Copyright © 2012 American Journal of Preventive Medicine. All rights reserved.)