['The aim of this study was to assess the association between the third component of the complement (C3) and other risk factors of coronary heart disease.', 'We evaluated 1200 individuals aged 25-74 years (600 men and 600 women). A strong relationship was shown between serum C3 and both body mass index (BMI, P<0.01) and fibrinogen (P<0.01). We found a significant, independent correlation with: platelet count (P<0.01), insulin level (P<0.01), triglycerides (P<0.01), low-density lipoprotein (LDL) cholesterol (P<0.01), and an inverse correlation with cigarette smoking (P<0.01).'] Is the third component of the complement ( C3 ) a marker of the risk of atherogenesis?