In the beginning of the 2000s, there was a rapidly growing interest in analysing the association between cognitive function and various health outcomes, generating the term ‘cognitive epidemiology’.1 Various hypotheses have been suggested for an association between lower cognitive function and disease, such as lower ‘bodily integrity’, and poorer health behaviour among persons with lower cognitive function. While these hypotheses were plausible for total mortality2 and mental health conditions,3 specific outcomes such as stroke, especially early onset, might not be as easily explained. Among the many outcomes assessed in the research on the association between cognitive function and health, findings regarding risk of early onset stroke have been inconsistent, partly because of the …