Objective: To study the association between blood pressure and risk of myocardial infarction in elderly subjects.
Design: Prospective cohort study.
Setting: The Rotterdam Study, a Dutch population-based study.
Participants: 6004 men and women aged > or = 55 years.
Main outcome measures: Fatal or non-fatal myocardial infarction (n = 190) during a 4-year follow-up.
Results: After excluding participants using blood pressure-lowering medication and participants with a history of myocardial infarction, increasing levels of systolic blood pressure (SBP) were associated with increasing risk of first myocardial infarction (P for trend < 0.0001). The relative risk (RR) for an SBP of 160 mmHg or higher was 5.7 (95% confidence interval (CI) 1.9-17.1) compared with an SBP below 120 mmHg. Increasing diastolic blood pressure (DBP) was also associated with increasing risk of first myocardial infarction, with the RR reaching 2.5 (95% CI 1.4-4.5) in subjects with values of 80-90 mmHg compared with values below 70 mmHg (P for trend < 0.05). Analyses in subjects aged 70 years and over showed that the positive associations between SBP and DBP and risk of first myocardial infarction remained at older age.
Conclusion: These findings in a relatively healthy cohort of elderly subjects do not provide evidence for a J- or U-shaped relation between SBP and DBP and risk of first myocardial infarction. They suggest that the risk of first myocardial infarction increases with increasing level of systolic and diastolic blood pressure and that this relationship persists into older age.