Longitudinal associations between social support trajectories and quality of life mediated by depressive symptoms: A 10-year cohort study of Wenchuan earthquake

Abstract

Introduction: Previous studies on associations between social support and quality of life (QoL) have usually employed a variable-centered approach, without considering individual variances in time-varying changes in social support. This study explores trajectories of social support and whether depressive symptoms mediate associations between social support trajectories and QoL 10 years after an earthquake. Methods: Seven hundred and forty-four Chinese adolescents exposed to the Wenchuan earthquake were surveyed on social support at 6-, 18-, and 24-months and depressive symptoms at 30-months postearthquake (T30m). They provided valid data on QoL after 10 years of the earthquake (T10y). The latent class growth analysis was used to estimate social support trajectories. Mediation analysis was then conducted to test whether depressive symptoms at T30m mediated associations between social support trajectories and QoL at T10y. Results: Three trajectories of social support were identified: low decreasing (31.6%), moderate decreasing (55.4%), and persistent high (13.0%) groups. Depressive symptoms significantly mediated the effects of social support trajectories (relative to the low support trajectory) on future QoL (95% CIs: 0.70–1.78 and 1.41–3.37 for moderate decreasing and persistent high groups, respectively). Conclusions: Social support shows individual differences over time. Moderate and high social support trajectories improve 10-year QoL partly by reducing depressive symptoms. Therefore, interventions aimed at enhancing social support and reducing depressive symptoms may be more effective in enhancing QoL in the aftermath of disasters.