Common carotid artery intima-media thickness and brain infarction : the Etude du Profil Génétique de l'Infarctus Cérébral (GENIC) case-control study. The GENIC Investigators.

BACKGROUND-The use of intima-media thickness (IMT) as an outcome measure in observational studies and intervention trials relies on the view that it reflects early stages of atherosclerosis and cardiovascular risk. There is little knowledge concerning the relation between IMT and brain infarction (BI). METHODS AND RESULTS-We investigated the relation of IMT with BI and its subtypes in 470 cases and 463 controls. Cases with BI proven by MRI were consecutively recruited and classified into subtypes by cause of BI. Controls were recruited among individuals hospitalized at the same institutions and matched for age, sex, and center. IMT was measured at the far wall of both common carotid arteries (CCA) using an automatic detection system. Adventitia-to-adventitia diameters and CCA-IMT were measured on transverse views; lumen diameter was computed using these measures. Mean (+/-SEM) CCA-IMT was higher in cases (0.797+/-0.006 mm) than in controls (0.735+/-0.006 mm; P<0. 0001). This difference remained after adjustment for lumen diameter and when analyses were restricted to subjects free of previous cardiovascular or cerebrovascular history. The difference in CCA-IMT between cases and controls was significant in the main subtypes. The risk of BI increased continuously with increasing CCA-IMT. The odds ratio per SD increase (0.150 mm) was 1.82 (95% confidence interval, 1.54 to 2.15); adjustment for cardiovascular risk factors slightly attenuated this relation (odds ratio, 1.73; 95% confidence interval, 1.45 to 2.07). CONCLUSIONS-An increased CCA-IMT was associated with BI, both overall and in the main subtypes. An increased IMT may help select patients at high risk for BI.