Coronary heart disease (CHD) has been associated with dementia, but the timing of risk before and after diagnosis has remained uncertain. A combined case-control and cohort analysis using UK Biobank data examined temporal patterns of dementia risk and was published in the Journal of the American Heart Association.

The study included 59,716 individuals with incident CHD and 144,595 matched controls. Dementia events were assessed during the 10 years preceding CHD diagnosis and during follow-up after diagnosis. Conditional logistic regression was used for pre-diagnosis analyses, and Cox proportional hazards models were used after diagnosis.

During the 10 years before CHD diagnosis, dementia developed in 364 individuals with CHD (0.61%) and 691 controls (0.48%), corresponding to higher odds of dementia among those with CHD (OR 1.30, 95% CI 1.14 to 1.48). Risk increased progressively as the diagnosis approached.

Within 1 year before CHD diagnosis, dementia occurred in 111 CHD cases (0.19%) and 140 controls (0.10%), representing nearly twofold higher odds (OR 1.91, 95% CI 1.48 to 2.47). After CHD diagnosis, dementia risk remained elevated over a median follow-up of 8.5 years (HR 1.52, 95% CI 1.44 to 1.61).

These findings suggest dementia risk may begin increasing years before clinical CHD diagnosis and remain elevated afterward, highlighting a potential window for earlier cardiovascular and cognitive risk assessment.