Association of Coronary Heart Disease Incidence with Carotid Arterial Wall Thickness and Major Risk Factors: The Atherosclerosis Risk in Communities (ARIC) Study, 1987-1993

TLDR

Few studies have determined whether greater carotid artery intima‑media thickness (IMT) in asymptomatic individuals is associated prospectively with increased risk of coronary heart disease (CHD). In the ARIC Study, carotid IMT was measured as the mean of B‑mode ultrasound measurements at six carotid sites and its relation to CHD incidence was assessed over 4–7 years of follow‑up in 12,841 adults aged 45–64 from four U.S. communities. Higher mean IMT (≥1 mm) was associated with a markedly increased hazard of incident CHD—HR 5.07 in women and 1.85 in men—though the association attenuated after adjusting for major risk factors yet remained significant, especially above 1 mm where women’s event rates approached men’s.

Abstract

Few studies have determined whether greater carotid artery intima-media thickness (IMT) in asymptomatic individuals is associated prospectively with increased risk of coronary heart disease (CHD). In the Atherosclerosis Risk in Communities Study, carotid IMT, an index of generalized atherosclerosis, was defined as the mean of MT measurements at six sites of the carotid arteries using B-mode ultrasound. The authors assessed its relation to CHD incidence over 4–7 years of follow-up (1987–1993) in four US communities (Forsyth County, North Carolina; Jackson, Mississippi; Minneapolis, Minnesota; and Washington County, Maryland) 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 women and 194 for men. In sex-specific Cox proportional hazards models adjusted only for age, race, and center, the hazard rate ratio comparing extreme mean IMT (≥1 mm) to not extreme (<1 mm) was 5.07 for women (95% confidence interval 3.08–8.36) and 1.85 for men (95% confidence interval 1.28–2.69). The relation was graded (monotonic), and models with cubic splines indicated significant nonlinearity. The strength of the association was reduced by including major CHD 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 above 1 mm their event rate was closer to that of men. Thus, mean carotid IMT is a noninvasive predictor of future CHD incidence. Am J Epidemiol 1997;146:483-94.