C-reactive protein and coronary heart disease in western Turkey

C-reactive protein (CRP) has been recognized as a useful marker for coronary or cardiovascular risk in healthy subjects or patients with coronary heart disease (CHD) in industrialized societies. We assessed whether CRP could serve as a marker of prevalent CHD risk in a cross-sectional study of a population with low cholesterol levels (4.61 mmol/L in men and 4.82 mmol/L in women) but higher prevalence of other risk factors. In 1,046 participants of the Turkish Adult Risk Factor Survey in 2000, high-sensitivity CRP as well as other risk variables were evaluated, and CHD was diagnosed, based on clinical findings and Minnesota coding of electrocardiograms at rest. Almost an equal number of men and women > or = 30 years of age constituted the population sample of the western regions of Turkey. Geometric mean value of CRP was 1.9 mg/L (interquartile range 0.8 to 4.3), without revealing a significant difference in gender. CRP was correlated with many variables, notably those involving central obesity, fibrinogen, and apolipoprotein-B, but not with smoking status (regardless of age adjustment). In multiple regression models, blood fibrinogen, waist circumference, total cholesterol, and physical activity grade were independently associated with log CRP concentrations. Among many risk variables, CRP quartiles and systolic blood pressure were, besides age and gender, the only significant independent determinants of CHD. The age-adjusted odds ratio for CHD in the highest as opposed to the lowest quartile was 4.48 (p < 0.001). Even after adjustment for the 5 previously mentioned determinants of CRP, a 4.2-fold increased risk of CHD still persisted between the highest and lowest quartiles. Thus, the observed increased risk was not in large part due to the intermediary effects of fibrinogen, nor were some indicators of insulin resistance, but interaction appeared to be independent of these effects. Thus, CRP values serve as a marker of prevalent CHD risk in populations with low cholesterol levels. This association is independent of, or in addition to, the effects of conventional risk factors, suggesting that the contribution of chronic low-grade inflammation to the atherothrombotic process is present even in the setting of low cholesterol levels.