Age-related progression of arterial stiffness and its elevated positive association with blood pressure in healthy people

Objective: Arterial stiffness occurs as a consequence of age and arteriosclerosis, but the mechanics of the progression of arterial stiffness along with age is not fully explored. We aim to investigate the age-related progression of arterial stiffness through the examination of 4659 healthy subjects aged from 20 to 75. Methods: The cardio-ankle vascular index (CAVI) was used as a marker of arterial stiffness. Piecewise linear regression model was utilized to analyze the association between different stages of age and arterial stiffness. The mean CAVI values of age groups were calculated to fit the linear regression and curvilinear regression models. We also constructed multiple regression models to examine the interactions of blood pressure and age on CAVI. Result: The regression coefficients (beta) of piecewise linear regression of each age group (<35, 35-44, 45-59, >59) were 0.07062, 0.03133, 0.03840 and 0.07272 for men, and 0.03342, 0.02025, 0.04826 and 0.10604 for women, respectively. The highest R square came from curvilinear regression for men (R-2 = 0.9220), and piecewise linear regression for women (R-2 = 0.9454). The interactions between each type of blood pressure and age were significant (all P < 0.001). Conclusion: There were various increased trends between different stages of age. Age-related progression of arterial stiffness could be better explained by a growth curve, rather than a straight line. In addition, blood pressure has an increasingly positive association with CAVI values as age increases. (C) 2014 Elsevier Ireland Ltd. All rights reserved.