We examined (i) the long-term association of cardiac troponin I at study baseline with cognitive trajectory and incident dementia in prospective analyses; (ii) how long before diagnosis of dementia the cardiac troponin I level has been elevated by modelling the backward trajectory of cardiac troponin I; and (iii) the association of cardiac troponin I with brain volume measures assessed 15 years later in a substudy of structural magnetic resonance imaging (MRI). Here, TNNI3 is linked to dementia.