Longitudinal associations of physical activity and pubertal development with academic achievement in adolescents

OBJECTIVE: We sought to investigate the longitudinal associations of moderate-to-vigorous physical activity (MVPA) and pubertal development with academic achievement in adolescents. METHODS: A total of 635 adolescents (283 boys, 352 girls) aged 11–13 years participated in the study. MVPA was assessed by the Health Behaviour in School-aged Children study questionnaire, and pubertal development was assessed by the Pubertal Development Scale at beginning of the 6th grade (baseline) and end of the 7th grade (follow-up). Grade point average (GPA) at the end of Grades 5 and 7 was computed from data acquired from the school registers. The data were analyzed using linear regression and analyses of covariance. RESULTS: In boys, MVPA was positively associated with GPA at baseline after adjustment for age (β = 0.144, 95% confidence interval (CI): 0.028−0.260, p = 0.028). In girls, the Pubertal Development Scale was positively associated with GPA at baseline (β = 0.104, 95%CI: −0.004 to 0.211, p = 0.058) and follow-up (β = 0.104, 95%CI: −0.002 to 0.211, p = 0.055) after adjustment for age, and these associations strengthened after further adjustment for MVPA (p < 0.05). Adolescents who were inactive at baseline or at baseline and follow-up had lower GPA during follow-up than their continuously highly active peers (mean difference = −0.301, 95%CI: −0.543 to −0.058, p = 0.009) and all other adolescents (mean difference = −0.247, 95%CI: −0.475 to −0.019, p = 0.029). These differences were greater in girls than in boys. CONCLUSION: Lower levels of MVPA were associated with lower GPA in boys at baseline. Girls who were continuously inactive had lower GPA over the follow-up period than those who were continuously active. Finally, earlier pubertal development was associated with better academic achievement in girls.