Carotid Artery Wall Hypertrophy With Age Is Related to Local Systolic Blood Pressure in Healthy Men

Carotid artery intima-media thickness (IMT) increases with advancing age in humans. The underlying mechanism of this increase is unknown, but data from animal studies suggest that a chronic increase in local distending pressure can act as a stimulus. To test this hypothesis, we studied a total of 129 healthy normotensive, nonobese, nonsmoking men aged 18 to 77 years. Brachial systolic blood pressure (SBP) was unchanged, but carotid SBP increased progressively with age (P<0.05). Carotid IMT and the ratio of carotid IMT to lumen (ultrasonography) increased progressively with age (P<0.05). Carotid IMT was approximately 50% greater in the older compared with the young men. Carotid SBP was positively related to carotid IMT (r=0.55, P<0.001). After carotid SBP was taken into account (ANCOVA), the age-related difference in carotid IMT was no longer statistically significant (P=0.22). We conclude that carotid IMT increases with age in healthy men in the absence of elevations in peripheral SBP. Carotid SBP increases progressively with advancing age in this population and is significantly related to the corresponding carotid wall hypertrophy. These results support the hypothesis that chronic increases in local distending pressure may be an important mechanism in the wall thickening that occurs with human aging in central elastic arteries.