Effect of depression on risks of Alzheimer’s disease and vascular dementia: A real-world longitudinal study
He Xu, Yueqing Wang, Weihao Shao, Jiajuan Yang, Xiaoxia Wei, Xunliang Tong, Chi Hu, Enying Gong, Luzhao Feng, Maigeng Zhou, Zuolin Lu, Ruitai Shao
Abstract
OBJECTIVES: To evaluate the relationship between depression and the risk of dementia. DESIGN: A real-world longitudinal study. SETTING: This comprehensive study involved elderly adults in Yichang, China, who were dementia-free at baseline from 2016 to 2023. PARTICIPANTS: Participants were followed until the onset of all-cause dementia, Alzheimer's disease, vascular dementia and unspecified dementia until December 31, 2023. EXPOSURE: Depression was identified using the International Classification of Diseases, 10th Revision codes, based on linked electronic health records. MEASURES: Multivariable-adjusted hazard ratio (HR) and 95% confidence intervals (CI) from the Cox proportional hazards regression models to evaluate the risks of all-cause dementia and its subtypes associated with prevalent depression. RESULTS: During an average follow-up of 3.63 years, we observed a total of 1 493 individuals developing dementia among 4 341 depressed and 43 214 matched non-depressed individuals (62.4% female; mean [SD] age at baseline 64.4 [11.1] years). Notably, a stronger association was observed between depression and the onset of Alzheimer's disease (adjusted HR, 4.96; 95% CI, 2.95-8.34) compared to vascular dementia (adjusted HR, 1.92; 95% CI, 1.18-3.11). Moreover, our study intriguingly revealed a U-shaped association between the risk of Alzheimer's disease and the duration of time an individual has been diagnosed with depression. CONCLUSIONS: Our findings unveil a significant association between depression and all-cause dementia, Alzheimer's disease and vascular dementia. The unique temporal association suggests that depression may serve as both a risk factor and a prodromal symptom for Alzheimer's disease, and solely as a risk factor for vascular dementia.