Objective: To determine whether common carotid artery intima-media thickness (IMT) is related to future cardiovascular disease.
Design: Nested case control study.
Setting: The suburb of Ommoord in Rotterdam, the Netherlands.
Method: As part of the Rotterdam study among 7983 subjects aged 55 years and over, ultrasound images of the common carotid artery were stored on videotape of 5965 subjects at baseline (1990-1993). Analysis (logistic regression) was based on 190 cases of cardiovascular disease (myocardial infarction and stroke), registered up to December 31, 1994. IMT was measured from videotape for all cases and a control sample of 1373 subjects who remained free from myocardial infarction and stroke during follow-up. The mean duration of follow-up was 2.7 years.
Results: The age and sex adjusted cardiovascular disease risk increased by 45% (95% confidence interval (95% CI): 25-69) per standard deviation increase (0.163 mm) in IMT. Stroke risk increased by 45% (95% CI: 25-69) per standard deviation increase and the risk of myocardial infarction increased by 43% (95% CI: 16-78). Additional adjustment for several cardiovascular risk factors attenuated the association.
Conclusion: Increased common carotid intima-media thickness was associated with subsequent cardiovascular events. These results support the use of carotid intima-media thickness measurements as a surrogate endpoint in observation and intervention studies. The value of IMT measurements for individual patients and cardiovascular screening merits further study.