Abstract
BACKGROUND: The present study aimed to analyze associations between device-measured physical activity and sedentary time during childhood with mental health-related outcomes throughout adolescence. METHODS: Data from the Millennium Cohort Study were used. Device-measured physical activity (i.e., light and moderate-to-vigorous physical activity) and sedentary time were assessed at 7 years. Internalizing and externalizing symptoms were assessed at three time points (11 years, 14 years, and 17 years) via the Strengths and Difficulties Questionnaire. Depressive symptoms were estimated using the Mood and Feelings Questionnaire at 14 years. Psychological distress was assessed using the six-item Kessler psychological distress scale at 17 years. Negative binomial regression models, adjusting for potential confounders were used. RESULTS: Among boys, greater time spent in moderate-to-vigorous physical activity at 7 years was associated with higher hyperactivity and lower peer problems throughout adolescence. Higher moderate-to-vigorous (incidence rate ratio [IRR]: 0.95; 95% confidence interval [CI]: 0.93-0.98), light (0.90; 0.85-0.95), and total activity time (0.95; 0.93-0.98) at 7 years were associated with lower, while sedentary time was associated with higher (1.11; 1.07-1.16) psychological distress at 17 years in the adjusted models. Girls who spent more time in light physical activity at 7 years were more likely to have lower hyperactivity levels over adolescence, while higher sedentary time at the same age was associated with higher hyperactivity levels. Higher sedentary time at 7 years was associated with higher depressive symptoms at 14 years (1.06; 1.01-1.10), whereas light physical activity at 7 years (0.91; 0.85-0.97) was associated with lower depressive symptoms at 14 years in the adjusted models. CONCLUSION: Higher moderate-to-vigorous, light physical activity, and lower sedentary time were associated with lower peer problems, depressive symptoms, and psychological distress throughout adolescence.