Impact of C-reactive protein on the likelihood of carotid atherosclerosis in Japanese adults.

OBJECTIVE Several cohort studies have shown a link between serum C-reactive protein (CRP) and subsequent cardiovascular disease; however, the role of CRP as an independent risk factor remains controversial. We therefore investigated the association between CRP and sclerotic lesions of common carotid atherosclerosis. PATIENTS AND METHODS We evaluated sclerotic lesions of common carotid arterial intima-media thickness (IMT) by ultrasonography in 139 men aged 67 +/- 15 years and 201 women aged 75 +/- 10 years. To investigate the relation between CRP and various confounding factors, subjects were divided into four groups based on the quartile of CPR. RESULTS Carotid IMT values were significantly higher in groups with higher CRP (p = 0.022). To identify the possible CRP level and risk factor interactions for IMT, multiple regression analysis for IMT was performed based on risk factors in subjects with a specific CRP level. It was shown that age, smoking status, systolic blood pressure (SBP) and LDL cholesterol were significantly associated with IMT in subjects in the lower CRP groups (CRP-1 approximately CRP-3), and age, SBP and presence of diabetes mellitus in the highest CRP group (CRP-4). To further investigate whether the interaction between CRP and conventional risk factors could influence IMT, a general linear model demonstrated that interaction between CRP and the presence of diabetes mellitus (F = 4.754 p = 0.030) was significantly associated with IMT, in addition to sex, age, SBP, antihypertensive drug use, LDL cholesterol and HDL cholesterol. CONCLUSIONS This finding indicates that the association between CRP and IMT significantly differed between subjects with and without diabetes mellitus.