Longitudinal trajectories of somatic and cognitive-affective depressive symptoms influence stroke risk across different populations: Three prospective cohort studies

BACKGROUND Depressive symptoms differ from clinical depression. However, the relationship between depressive symptom trajectories and stroke risk across diverse geographic regions remains unclear. AIM To address the gap in the existing understanding of the relationship between depressive symptom trajectories and stroke risk, the current study utilized three representative cohorts. METHODS In this study, we used three representative cohorts from Asia, Europe, and the Americas: China Health and Retirement Longitudinal Study (CHARLS), English Longitudinal Study of Ageing (ELSA), and Health and Retirement Study (HRS). Depressive symptoms were assessed using the 8-item Center for Epidemiological Studies Depression scale and categorized into somatic and cognitive-affective subtypes. The trajectories of depressive symptoms were monitored over four surveys starting from baseline and classified into five distinct states: persistently low, decreasing, fluctuating, increasing, and consistently high. Self-reported physician diagnoses were used to evaluate the subsequent stroke events. Hazard ratios (HRs) and 95% confidence intervals (95%CIs) were computed using Cox proportional-risk models adjusted for potential confounding factors. RESULTS A total of 7990 participants from CHARLS (females: 52.3%, mean age: 63.4 years), 5642 participants from ELSA (females: 56.2%, mean age: 63.7 years), and 12260 participants from HRS (females: 61.4%, mean age: 64.7 years) participated in this study. The median follow-up periods were 5 years for CHARLS, 8 years for ELSA, and 10 years for HRS. In comparison with the persistently low trajectory, consistently high and fluctuating trajectories of total depressive symptoms increased the risk of stroke in all three cohorts (CHARLS: HR = 1.80, 95%CI: 1.36-2.38; ELSA: HR = 1.50, 95%CI: 1.02-2.21; HRS: HR = 1.45, 95%CI: 1.29-1.62 for consistently high; CHARLS: HR = 1.47, 95%CI: 1.14-1.90; ELSA: HR = 1.44, 95%CI: 1.17-1.77; HRS: HR = 1.26, 95%CI: 1.13-1.41 for fluctuating). Increasing trajectories enhanced the risk in the European cohort (ELSA: HR = 1.71, 95%CI: 1.06-2.74), while decreasing trajectories did not increase stroke risk in any cohort. For somatic depressive symptoms, consistently high and fluctuating trajectories increased the risk of stroke across all cohorts (CHARLS: HR = 2.16, 95%CI: 1.67-2.79; ELSA: HR = 1.94, 95%CI: 1.34-2.81; HRS: HR = 1.79, 95%CI: 1.49-2.15 for consistently high; CHARLS: HR = 1.35, 95%CI: 1.20-1.62; ELSA: HR = 1.56, 95%CI: 1.27-1.92; HRS: HR = 1.33, 95%CI: 1.20-1.46 for fluctuating). Increasing trajectories only increased the risk in the European cohort (ELSA: HR = 1.95, 95%CI: 1.11-3.43), while decreasing trajectories did not increase stroke risk in the European and American cohorts. For cognitive-affective depressive symptoms, consistently high and fluctuating trajectories increased the risk in the Asian and European cohorts (CHARLS: HR = 2.06, 95%CI: 1.52-2.81; ELSA: HR = 1.25, 95%CI: 1.02-1.54 for consistently high; CHARLS: HR = 1.63, 95%CI: 1.23-2.16; ELSA: HR = 1.58, 95%CI: 1.11-2.24 for fluctuating). Increasing trajectories increased the risk only in the American cohort (HRS: HR = 14.67, 95%CI: 1.87-114.91). CONCLUSION Consistently high and fluctuating trajectories of total and somatic depressive symptoms were associated with an increased risk for stroke across all populations. Consistently high, fluctuating, and increasing trajectories of cognitive-affective symptoms pose a risk for certain populations. These findings highlight the importance of targeted interventions for managing depressive symptoms as potential strategies for stroke prevention, particularly in regions where specific symptom trajectories are prevalent.