Dementia Risk in the Decade Before and After Coronary Heart Disease Diagnosis: Hybrid Case–Control and Cohort Study

BACKGROUND: Although coronary heart disease (CHD) is associated with increased dementia risk, the temporal dynamics of this risk relative to CHD diagnosis remain unclear. METHODS: By using UK Biobank data, we conducted a combined case-control and cohort study including 59 716 incident CHD cases and 144 595 matched controls. Conditional logistic regression and Cox proportional hazards regression were employed to assess the associations between incident dementia and CHD over the decade preceding CHD diagnosis and in the period following diagnosis until the end of follow-up. RESULTS: During the 10 years preceding CHD diagnosis, 364 (0.61%) patients with CHD and 691 (0.48%) controls developed dementia, corresponding to a significantly elevated risk (odds ratio [OR], 1.30 [95% CI 1.14-1.48]) that demonstrated an incremental increase with the proximity of CHD diagnosis. Notably, within the year before CHD diagnosis, 111 (0.19%) patients with CHD and 140 (0.10%) controls developed dementia, resulting in a nearly 2-fold increase in risk among patients with CHD (OR, 1.91 [95% CI, 1.48-2.47]). After diagnosis, patients with CHD had an elevated dementia risk over a median 8.5-year follow-up (hazard ratio [HR], 1.52 [95% CI, 1.44-1.61]). CONCLUSIONS: Dementia risk begins rising at least a decade before CHD diagnosis, peaking near the time of clinical diagnosis. These findings underscore a critical preclinical phase during which preventive interventions may mitigate subsequent neurodegenerative outcomes.