BACKGROUND: The American Heart Association (AHA) recently developed the Cardiovascular Health Index (CVHI), a health metric consisting of 7 modifiable risk factors. The relationship of the CVHI with preclinical markers, such as carotid intima-media thickness (CIMT) has not been assessed. METHODS: We examined 490 male monozygotic and dizygotic twins without overt cardiovascular disease. CIMT was measured using B-mode ultrasonography. Each of the 7 CVHI components (blood pressure, fasting glucose, total cholesterol, body mass index, physical activity, healthy diet, and smoking) was given a point score of 0, 1, or 2 to represent poor, intermediate, or ideal health, respectively. A CVHI summation score was computed (range 0 to 14) and categorized as inadequate (0 to 4), average (5 to 9), or optimum (10 to 14) cardiovascular health. Mixed-model regression was used to examine the association of the CVHI with CIMT. RESULTS: The mean age of the twins was 55.4 years, and 61% were monozygotic. The mean CIMT was 0.75 (± 0.11) mm and the mean CVHI score was 7.7 (± 2.1). There was an inverse correlation between CVHI and CIMT (Spearman r=-0.22, P<0.01). For every 5-unit increase in overall CVHI score (indicating better cardiovascular health category), CIMT decreased by 0.045 mm (P<0.001) after adjusting for demographic variables and other confounders. Within monozygotic twin pairs, a 5-unit increment in CVHI score was associated with a 0.05 mm lower CIMT (P<0.001). CONCLUSIONS: The CVHI is independently associated with CIMT and the association is not confounded by shared genetic and other familial factors.