ASSOCIATION OF CORONARY HEART-DISEASE INCIDENCE WITH CAROTID ARTERIAL-WALL THICKNESS AND MAJOR RISK-FACTORS - THE ATHEROSCLEROSIS RISK IN COMMUNITIES (ARIC) STUDY, 1987-1993

Few studies have determined whether greater carotid artery intima-medi a thickness (IMT) in asymptomatic individuals is associated prospectiv ely with increased risk of coronary heart disease (CHD). In the Athero sclerosis Risk in Communities Study, carotid IMT, an index of generali zed atherosclerosis, was defined as the mean of IMT measurements at si x sites of the carotid arteries using B-mode ultrasound. The authors a ssessed its relation to CHD incidence over 4-7 years of follow-up (198 7-1993) in four US communities (Forsyth County, North Carolina; Jackso n, Mississippi; Minneapolis, Minnesota; and Washington County, Marylan d) from samples of 7,289 women and 5,552 men aged 45-64 years who were free of clinical CHD at baseline. There were 96 incident events for w omen and 194 for men. In sex-specific Cox proportional hazards models adjusted only for age, race, and center, the hazard rate ratio compari ng extreme mean IMT(greater than or equal to 1 mm) to not extreme (<1 mm) was 5.07 for women (95% confidence interval 3.08-8.36) and 1.85 fo r men (95% confidence interval 1.28-2.69). The relation was graded (mo notonic), and models with cubic splines indicated significant nonlinea rity. The strength of the association was reduced by including major C HD risk factors, but remained elevated at higher IMT. Up to 1 mm mean IMT, women had lower adjusted annual event rates than did men, but abo ve 1 mm their event rate was closer to that of men. Thus, mean carotid IMT is a noninvasive predictor of future CHD incidence.