Exploring stress and health in Swedish adolescent life — a physical activity perspective on resilience, socioeconomic status and academic achievement

Abstract

This thesis is primarily motivated by the increasing mental health problems (MHPs) among adolescents in Sweden. In addition, it addresses three secondary related challenges in adolescent life: insufficient physical activity; socioeconomic disparities; and poor academic achievement. The overall aim of this thesis is to provide in-depth knowledge of adolescent stress and health, with special emphasis on physical activity.

Using data from the Study of Adolescence Resilience and Stress (STARS) and linked register data, this thesis examined interrelations between physical activity, MHPs, cardiovascular risk factors, coping strategies, socioeconomic conditions, and academic achievement. In Paper I, partial least squares regression showed that while all intensities of physical activity were negatively associated with cardiovascular risk factors and sedentary time was positively associated with these risk factors, only higher-intensity physical activity was negatively associated with MHPs. In Paper II, mediation analysis identified the coping strategy “shift-persist” as a pathway linking higher-intensity out-of-school physical activity (oosPA) to lower levels of MHPs. In Paper III, linear regression demonstrated social gradients in MHPs by income and parental education, and mediation analysis within the potential outcomes framework indicated that higher-intensity oosPA mediated this association, at least among girls. In Paper IV, linear and logistic regression using generalised estimating equations, with school specified as the clustering variable, showed that MHPs contributed to a social selection process in academic achievement. Higher-intensity oosPA did not moderate this association.

Together, these findings highlight the importance of ensuring that adolescents engage in physical activity, including aerobic physical activity, and that in particular girls from socioeconomically disadvantaged backgrounds, have opportunities for out-of-school aerobic exercise. Additionally, there is a need to identify factors that promote resilience to stress related to academic achievement.