Sedentary behavior in adolescents: the 11-year follow-up of the 1993 Pelotas (Brazil) birth cohort study

The aim of this study was to estimate the prevalence of sedentary behavior and investigate associated factors in adolescents 11 years of age from the 1993 birth cohort in Pelotas, Rio Grande do Sul State, Brazil. Sedentary behavior was investigated with a questionnaire, and was defined as spending more than two hours per day watching television, playing videogames, or using the computer. Of the 4,452 adolescents interviewed, 98% reported watching television, 44% playing videogames, and 22% using the computer. The average time spent on each of these electronic media was 197, 36, and 17 minutes per day, respectively. Prevalence of sedentary behavior was 79.7% (95% CI: 78.6; 80.9) and showed a positive association with socioeconomic level and nutritional status and a negative association with well-being. These 11-year-olds spent extensive time at TV viewing, videogames, and the computer. Special attention should be given to the most exposed groups of adolescents, including the more affluent, overweight, and those with limited schooling.