['The aim of this study was to evaluate the association between severe periodontitis and sub-clinical atherosclerosis in young (< or =40 years) systemically healthy individuals.', 'Ninety systemically healthy subjects, 45 affected by severe periodontitis (mean age 36.35+/-3.65 years) and 45 controls without a history of periodontal disease (mean age 33.78+/-3.28 years), were enrolled in this study. Patients and controls were paired for age, gender, body mass index and smoking habits. Carotid intima-media thickness (IMT) was bilaterally assessed by ultrasonography at the level of common carotid artery. Traditional cardiovascular risk factors for atherosclerosis were also evaluated.', 'The overall mean carotid IMT was 0.82+/-0.13 mm in the test group and 0.72+/-0.07 mm in the control group ( p<0.0001). Stepwise regression analysis showed that periodontitis ( p<0.0001) and regular physical activity ( p=0.0009) were predictor variables of overall mean carotid IMT. When considering an IMT> or =0.82 mm as the critical index of increased cardiovascular risk, periodontal patients overcame this threshold compared with healthy patients by an odds ratio=8.55 [confidence interval 95%: 2.38; 39.81]. No investigated haemostatic variable was associated with increased carotid IMT.'] Is severe periodontitis in young adults associated with sub-clinical atherosclerosis?