Depressive Symptom Trajectories and Incident Pain: The Role of Nocturnal Sleep Duration in Two Prospective Cohort...

This study aims to investigate the mediating role of nocturnal sleep duration in the association between depressive symptoms trajectories and subsequent pain outcomes. Using data from the English Longitudinal Study of Ageing (ELSA) and the China Health and Retirement Longitudinal Study (CHARLS), 6,874 participants were included. Latent class mixture models (LCMM) were employed to identify depressive symptoms trajectories. Logistic regression analysis was conducted to examine the association between these trajectories and pain. Three depressive symptoms trajectories were identified in both cohorts: low-stable (class 1), increase-then-decrease (class 2), and decrease-then-increase (class 3). In ELSA, classes 2 and 3 exhibited 93% (OR = 1.93, 95% CI: 1.47, 2.52) and 51% (OR = 1.51, 95% CI: 1.20, 1.88) increases in pain risk, respectively. In CHARLS, class 2 exhibited a 183% (OR = 2.83, 95% CI: 2.32, 3.47) and class 3 a 173% (OR = 2.73, 95% CI: 2.29, 3.26) increase in pain risk. In ELSA, nocturnal sleep duration explained 5.97% (95% CI: 0.0081, 0.1460) of the association between class 2 and pain onset, and 6.07% (95% CI: 0.0080, 0.1811) for class 3. In CHARLS, the mediation proportions were 4.44% (95% CI: 0.0019, 0.0915) for class 2 and 2.74% (95% CI: 0.0022, 0.0558) for class 3. Different trajectories of depressive symptoms are associated with varying pain risks, a relationship partially mediated through sleep. These findings underscore the necessity of ongoing management of depressive symptoms and sleep conditions for pain prevention.