Abstract
PURPOSE: The aim of the present study was to analyze the associations of youths' sedentary behavior (SB) with parents' and siblings' SB and physical activity (PA), as well as the associations of youths' coparticipation with parents, siblings, and friends in PA and SB with youths' SB. METHODS: The sample consisted of 1543 youths (12.02 ± 2.51 years; 788 boys) enrolled in the baseline cohort of the UP&DOWN study. SB was assessed by accelerometry and questionnaire. Participants reported the time spent by their parents and siblings watching television, playing videogames, surfing the Internet, sitting/resting, and doing PA. Further, participants reported coparticipation with parents, siblings, and friends in these activities. Linear mixed models, including school and city as random effects, were performed. RESULTS: Parents' television time was positively associated with youths' screen-based SB. Coparticipation with friends in playing videogames (in boys) and in surfing the Internet (in girls) showed a positive association with screen-based SB and a negative association with educational-based SB. Moreover, coparticipation with siblings and friends in PA was inversely associated with accelerometer-based SB in boys and girls. CONCLUSION: Our results emphasize the important role of social modeling in the development of sedentary lifestyles in youths. Interventions aimed at reducing health risk behaviors in youths could be more effective if they are oriented from a social perspective that involves their families and networks of their closest friends.