Effect of Plasma Fibrinogen, High-Sensitive C-Reactive Protein, and Cigarette Smoking on Carotid Atherosclerosis: The Suita Study

BackgroundFew studies have reported on the association between inflammatory markers and atherosclerosis by smoking status. We investigated the effect of plasma levels of fibrinogen and high-sensitive C-reactive protein (hsCRP) on subclinical atherosclerosis stratified by smoking in a general urban population.MethodsFrom participants of the Suita study without a history of cardiovascular diseases, a total of 2502 subjects (805 men, median age 64 years) who underwent carotid ultrasonography were enrolled. Subjects were divided into current smokers (n = 566) and never-smokers. Ex-smokers were not included in the study. Each group was subdivided according to the median levels of markers (plasma fibrinogen [2.99 g/L] and hsCRP [.51 mg/L]) and the smoking amounts. We compare the adjusted maximum and mean intima–media thickness (IMT).ResultsIn men and women, maximum IMT and mean IMT of the high fibrinogen and high hsCRP (Fib(H)CRP(H)) with smoking were thicker than those of the low fibrinogen and low hsCRP (Fib(L)CRP(L)) without smoking, the Fib(L)CRP(L) with smoking, and the Fib(H)CRP(H) without smoking after adjusting for covariates. The Fib(L)CRP(L) with smoking had thicker IMTs than the Fib(L)CRP(L) without smoking. There was a dose-dependent smoking effect on IMT in men. These trends were similar in age 60, 65, and 70.ConclusionsPlasma fibrinogen and hsCRP levels were related to multivariate-adjusted IMT, and smoking was associated with IMT in men. The combination of plasma fibrinogen and hsCRP levels could be a potential marker on subclinical carotid atherosclerosis in urban people.