[Carotid intima-media thickness and the occurrence of plaque in centenarians--data from the Tokyo Centenarian Study]

We studied carotid intima-media thickness at non-plaque sites and the occurrence of plaque in 25 centenarians (8 men and 17 women) living in Tokyo. The studies were done by B-mode ultrasonography and the results were compared with those found in 126 healthy subjects (83 men and 43 women) aged 28 to 82 years. The intima-media complexes were diffusely thickened in the centenarians; average thickness at bifurcations and at three sites in each common carotid artery ranged from 0.91 to 1.12 mm. The thickness was not associated with blood pressure or with serum lipid concentration. The thickness in the control group correlated with age, and that relationship fit a second degree equation. The expected values of mean intima-media thickness of the common carotid arteries at age 100 were computed with these equations; the predicted values ranged from 0.92 to 0.98 mm, which are close to the mean values measured in the centenarians (0.95 to 1.05 mm). However, the variations in intima-media thickness were greater in the centenarians. The prevalence of plaque in the centenarians was 40% for the right carotid artery and 36% for the left, but the prevalence among those in the eighth decade of life was 9.5% for both sides; plaque was not found among subjects in the sixth decade of life or younger. These data suggest that the degree of carotid arteriosclerosis is one factor that limits human longevity.