INTRODUCTION: The independent and joint effect of ischemic heart disease (IHD) and coexisting atrial fibrillation (AF) and heart failure (HF) on dementia risk is largely unknown.

METHODS: This population-based cohort study included 2568 dementia-free participants (age ≥60 years) in SNAC-K, who were regularly examined from 2001–2004 through 2013–2016. Dementia was diagnosed following the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria. Global cognitive function was assessed using a global cognitive composite z-score derived from five cognitive domains. Data were analyzed using Cox, Fine-Gray, and linear mixed-effects models.

RESULTS: Overall, IHD at baseline was associated with multivariable-adjusted hazard ratio (HR) of 1.39 (95% confidence interval = 1.06−1.82) for dementia and multivariable-adjusted β-coefficient of −0.02 (−0.03 to −0.01) for annual changes in global cognitive z-score, independent of AF, HF, and cerebrovascular disease. Coexisting AF or HF did not add further risk to dementia and cognitive decline.

DISCUSSION: IHD is independently associated with dementia and cognitive decline in older adults, whereas coexisting AF/HF is not associated with an increased risk.