In this cohort study, we assessed the association between depression and the risk of Alzheimer's disease from data obtained from the 2002 to 2013 Korean National Health Insurance Service-Elderly Cohort Database, which accounts for 10% of the South Korean population aged > 60 years. A total 518,466 patients were included in the analysis and followed up, unless they were excluded due to death or migration. Patients who sought treatment for depression or dementia within 1 year of the washout period and who were diagnosed with dementia within the 1-year period of the diagnosis of depression were excluded from the study. The risk of dementia was analysed using Cox proportional hazards models. Patients with a history of depression during the follow-up period were at a higher risk of Alzheimer's disease than those without a history of depression (HR 3.35, CI 3.27-3.42). The severe-depression group exhibited the highest risk of Alzheimer's disease (HR 4.41, CI 4.04-4.81), while the mild-depression group exhibited a relatively lower risk of Alzheimer's disease (HR 3.31, CI 3.16-3.47). The risk of Alzheimer's disease was associated with depression history and an increased severity of depression increased the risk of Alzheimer's disease.
© 2021. The Author(s).