Change in device-measured physical activity assessed in childhood and adolescence in relation to depressive symptoms: a general population-based cohort study.

Abstract

Aim: Evidence for a link between physical activity and mental health in young people is hampered by weak evidence. By utilising repeat assessments of device-measured physical activity, we examined the association of within-individual variation in free-living activity over 7 years with depressive symptoms.

Methods: This was a prospective cohort study of a nationally representative sample of children born in the UK (n=4,898). Physical activity was quantified using accelerometry at age 7 and age 14. Main outcome was depressive symptoms, based on the Short Moods and Feelings Questionnaire, assessed at age 14.

Results: After adjustment for socio-economic status, body mass index, and psychological problems at baseline, higher levels of light intensity activity at age 7 in girls was associated with a lower likelihood of having depressive symptoms at follow up (odds ratio, 0.79; 95% CI, 0.61, 1.00), although no associations were observed for moderate to vigorous activity or sedentary behaviour. Girls who transitioned from low baseline activity to higher levels at follow up experienced a lower risk of depressive symptoms (odds ratio, 0.60; 95% CI, 0.39 – 0.92) compared to the inactive reference category. Null associations were observed in boys. Participants who consistently met the currently recommendation of 60 min-d moderate-vigorous activity at both age 7 and 14 years of age experienced the lowest risk of depressive symptoms (odds ratio, 0.55;95% CI, 0.34, 0.88).

Conclusion: To prevent depressive symptoms in adolescence, policies to increase physical activity from mid-childhood may have utility.