Carotid plaque and intima-media thickness assessed by B-mode ultrasonography in subjects ranging from young adults to centenarians

Background and Purpose - To investigate relationships among plaque formation, increasing intima-media thickness, and age, we examined ultrasonographically carotid arteries of subjects who had no major atherosclerotic risk factors and who ranged in age from young adults to centenarians. Methods - We studied 319 healthy subjects (154 men, 165 women; age range, 21 to 105 years) with no history of hypertension, diabetes mellitus, or atherosclerotic disease. Mean intima-media wall thickness (IMT) of common carotid arteries at plaque-free sites and prevalence of plaques were evaluated by B-mode ultrasound. Results - Mean common carotid IMT increased in a linear manner with age for all decades of life, including centenarians [IMT=(0.009×Age)+0.116] (r=0.83). In centenarians (n=30), intima-media complexes were diffusely thickened (mean IMT, 1.01 mm). Plaque prevalence increased up to the tenth decade of life (83.3%, n=30) but decreased in centenarians (60.0%). IMT and plaque prevalence were closely associated in the seventh and eighth decades of life but not at older ages. Conclusions - The present study indicates that increased IMT is a physiological effect of aging that corresponds to diffuse intimal thickening, especially in very elderly persons, and that IMT is distinct from pathological plaque formation.