Patterns of depressive symptoms over 16 Years with incident dementia: The Health and Retirement Study

The associations of patterns of depressive symptoms, including trajectories of depressive symptoms and significant depressive symptoms among older adults over a long period of time with incident dementia are not frequently studied. We aimed to examine the associations of patterns of depressive symptoms among older adults with incident dementia. Participants of the Health and Retirement Study from 1994 to 2018 with information of incident dementia and complete measurements of depressive symptoms were included. Depressive symptoms assessed on 8 waves between 1994 and 2010 using the 8-item Center for Epidemiologic Studies Depression (CES-D) Scale. Significant depressive symptoms were defined as ≥4 points in the CES-D. Trajectories of depressive symptoms and significant depressive symptoms were identified. Cox proportional hazards models were used to examine the associations of patterns of depressive symptoms with incident dementia. A total of 6317 participants were included in the analysis. Over the follow-up period of 8 years, trajectories of “increase from mild” (hazards ratio (HR): 1.84, 95% confidence interval (CI): 1.29, 2.63) and “persistently high” (HR: 1.76, 95% CI: 1.17, 2.65) depressive symptoms were associated with higher risk of incident dementia, after adjustment for covariates. Future studies are needed to examine the interaction of depression in different stages of life on incident dementia. Studies are also expected to estimate the effect of preventing dementia through reducing depressive symptoms.