Determinantes psicossociais e ambientais das trajetórias de atividade física em adolescentes

Abstract

Introduction: The study of the determinants of physical activity (PA) is essential to understand the reasons that lead people to practice physical activity. However, most studies of the determinants used analyses that consider only the average value, considering that the behavior of adolescents is homogeneous and not assuming that adolescents may present different trajectories of physical activity. The study of trajectories is an approach that allows analyzing the development (stability or change) of a person's behavior over a period of time, creating groups of people with common characteristics. Since physical activity is a complex and multidetermined behavior, the study of trajectories is an appropriate method to identify groups of people and the possible changes in these groups over time. Objective: In this perspective, the present study aimed to identify the trajectories of physical activity and analyze whether psychosocial factors (self-efficacy - SE and social support - SS) and environmental factors (perceived characteristics of the neighborhood environment - PCNE) are determinants of the trajectories in adolescents, over a three-year follow-up. Methods: This is a longitudinal observational study that used data from the LONCAAFS Study (2014 to 2017), with 462 adolescents, aged 10 to 13 years in 2014 (mean age of 11.8 ± 0.8 years), of both sexes (50.2% females), from public schools in João Pessoa, Paraíba, Brazil. A questionnaire applied through interviews was used to collect the following variables: sex, age, economic class, time of residence in the neighborhood, and scales to measure self- efficacy, social support (father, mother, and friends), and perceived characteristics of the neighborhood environment. Latent Class Growth Curve analysis was performed to identify physical activity trajectories in the Mplus 7.0 program, and Multinomial Regression analysis was used to analyze whether psychosocial (self-efficacy and social support) and environmental (perceived characteristics of the neighborhood environment) factors are determinants of the trajectories in the Stata 13.0 program. Sex, age, and economic class were tested as potential moderators in the relationship between psychosocial and environmental determinants and physical activity trajectories in the Stata 13.0 program. Results: Four PA trajectories were identified: maintaining low level of PA, maintaining intermediate level of PA, declining level of PA, and increasing level of PA. Statistically significant associations were found between SE, SS, and PCNE and PA trajectories. Adolescents who belonged to the group of increased and/or high levels of SE (OR = 2.81; 95%CI: 1.89 - 4.19), father's SS (OR = 4.73, 95%CI: 2.46 - 9.12) and friends' SS (OR = 24.53, 95%CI: 8.91 - 67.58) were more likely to belong to the trajectory of increased PA level, and adolescents who belonged to the group of declining mother's SS level (OR = 2.82, 95%CI: 2.03 - 3.91) and declining perception of practice locations (OR = 2.40, 95%CI: 1.57 - 3.71) were more likely to belong to the trajectory of declining PA level. Conclusion: It is concluded that psychosocial factors (self-efficacy and social support) and environmental factors (perceived characteristics of the neighborhood environment) were shown to be determinants of the trajectories of physical activity practice in adolescents.