Unrecognized myocardial infarction and the risk of stroke: the Rotterdam Study

To investigate the relationship between unrecognized myocardial infarction and the risk of stroke in a population-based cohort study.

We followed 6,439 participants from the Rotterdam Study for stroke until January 2002. Participants were free from stroke, and presence of myocardial infarction was assessed at baseline (1990-1993). We calculated hazard ratios of stroke for persons with unrecognized or recognized myocardial infarction compared with persons without myocardial infarction. Analyses were adjusted for age, sex, and cardiovascular risk factors.

In 52,915 person-years of follow-up, 505 strokes occurred. Recognized myocardial infarction was only borderline associated with an increased risk of stroke. Unrecognized myocardial infarction increased the risk of stroke by 76% (age- and sex-adjusted hazard ratio 1.76, 95% CI 1.31 to 2.37). Stratification by sex showed that the increased risk was only found in men (hazard ratio for men 2.53, 95% CI 1.68 to 3.81; hazard ratio for women 1.27, 95% CI 0.82 to 1.96). After adjusting for cardiovascular risk factors at baseline, the risk remained significantly increased in men (hazard ratio for stroke 2.13, 95% CI 1.35 to 3.36). Subtyping of strokes revealed that unrecognized myocardial infarction was particularly associated with cortical ischemic strokes (hazard ratio for men 3.57, 95% CI 1.79 to 7.12).

Men with unrecognized myocardial infarction have an increased risk of stroke.