Trajectories of depressive symptoms in older adults: Correlates and consequences for mortality

Depression in old age often has a poor clinical course, although there is substantial variability in depressive symptom trajectories. We aimed to characterise old-age depressive symptom trajectories, assess their multifactorial correlates, and their impact on mortality.

We used cohort data from 2118 dementia-free community-dwelling adults aged ≥60 years participating in the Swedish National study on Aging and Care in Kungsholmen (SNAC-K). Depressive symptoms were evaluated using the Montgomery-Åsberg Depression Rating Scale at baseline and 1-3 follow-ups over 9 years. Sociodemographic (age, sex, marital status, socioeconomic status), psychosocial (social connections and support), clinical (multimorbidity), and functional (gait speed; cognitive impairment) factors at baseline were considered as trajectory correlates. Generalised growth mixture models and multinomial logit models estimated depression trajectories and their correlates. Cox proportional hazard models estimated all-cause mortality risk.

Three trajectory classes emerged: low, increasing, and U-shaped trajectories of depressive symptoms. Compared to the low trajectory, socioeconomic status involving high financial strain and poor social support was more common in the increasing and U-shaped trajectories. Slow gait speed was linked to higher odds of increasing depressive symptoms, while greater multimorbidity was associated with the U-shaped trajectory. The increasing and U-shaped trajectories were associated with higher mortality risk, and the association for increasing was robust to the adjustment of covariates.

Depressive symptom trajectories in late life are heterogeneous and linked to diverse socio-economic, clinical, and functional factors, some of which are trajectory-specific. Given its association with mortality, older people should be carefully monitored for depressive symptomatology.