Longitudinal association between consecutive moderate-to-vigorous physical activity and the risk of depression among depressed and non-depressed participants: A nationally representative cohort study.

The association between moderate-to-vigorous physical activity (MVPA) with depression are clear but needs to be investigated considering dynamic changes in MVPA. We investigated the association of longitudinal changes in MVPA with depression-related outcomes among depressed and non-depressed participants. From 209,095 depressed and 3,777,173 non-depressed participants of South Korea, MVPA was assessed from health screenings during period 1 (2014-15) and 2 (2016-17) using self-reported questionnaires. Participants were followed up from January 1, 2018 to 1-year and 3-year for any diagnosis of depression. Adjusted odds ratio (aOR) and 95 % confidence interval (CI) were calculated using multivariable-adjusted logistic regression analysis. From depressed participants, consistently highly active participants showed the lowest odds for incident depression (aOR 0.81; 95 % CI 0.70-0.95), while those who increased MVPA showed the lowest odds for depressive symptom (aOR 0.77; 95 % CI 0.72-0.82). When combining MVPA status during period 0 (2012-13) for the longitudinal analysis, the participant with depression at period 1 showed a lower odds if they maintained to be physically active before and after depression diagnosis (from period 0 to period 2). We found epidemiologic evidence that longitudinal evaluation for MVPA from pre-depression state may be important on analyzing depression-related risk.