Objective-Interleukin-6 (IL-6) and C-reactive protein (CRP) are markers of systemic vascular inflammation that herald atherothrombosis and may have important interrelationships with traditional cardiovascular risk factors. Methods and Results-We conducted a cross-sectional analysis among 340 apparently healthy women enrolled in the Women's Health Study. In unadjusted analyses, higher levels of IL-6 and CRP were seen with increasing body mass index (BMI), systolic and diastolic blood pressure, and smoking exposure. IL-6 levels were related to the frequency of alcohol intake (Pϭ0.002) and showed an inverse relationship with exercise frequency and hormone replacement therapy (PϽ0.0001 for both). CRP levels increased with hormone replacement therapy (Pϭ0.0002). Associations among IL-6, CRP, and lipid levels were minimal. Overall, mean levels of IL-6 and CRP increased with increasing numbers of clinical risk factors (PϽ0.0001). In multivariate analyses, independent relationships were seen between levels of IL-6 and age, BMI, smoking, systolic blood pressure, alcohol use, presence of diabetes, and frequency of exercise. CRP was associated with age, BMI, systolic blood pressure, high density lipoprotein, smoking, and hormone replacement therapy in adjusted analyses. Key Words: interleukin-6 Ⅲ C-reactive protein Ⅲ risk factors Ⅲ inflammation Ⅲ atherosclerosis A ccumulating evidence suggests that inflammatory processes, in part, mediate the development and progression of atherosclerosis. 1,2 In this regard, several circulating proinflammatory molecules have been associated with thrombotic cardiovascular events. Included among these are acutephase proteins, cellular adhesion molecules, selectins, and cytokines. 3 The stimuli activating or inciting the thrombotic process are protean but may be associated with various clinical cardiovascular risk factors. 4
Conclusions-Plasma
See page 1514The plasma cytokine interleukin-6 (IL-6) plays an important role in mediating inflammation and is a central stimulus for the acute-phase response. 5 In particular, IL-6 induces the hepatic synthesis of C-reactive protein (CRP), a known proinflammatory marker of atherothrombotic vascular disease. Although circulating levels of IL-6 and CRP are therefore physiologically linked, it remains unclear whether these markers of systemic vascular inflammation track with one another in respect to various traditional risk factors in healthy individuals. However, IL-6 and CRP have independently demonstrated associations with cardiovascular events and mortality among apparently healthy men and women. 6 -8 The interplay between the inflammatory process, cardiovascular risk factors, and atherothrombosis is complex. 9 Despite evolving theories regarding IL-6 and CRP in the central mechanisms of inflammation and atherogensis, 10 there exists a paucity of data coherently relating clinical cardiovascular risk factors with circulating levels of systemic vascular inflammatory markers in healthy individuals.Given this, we sought to determine the relationship a...