Women exhibit a greater age-related increase in proximal aortic stiffness than men

Background: Large artery mechanical properties are a major determinant of pulse pressure and cardiovascular outcome. Sex differences in these properties may underlie the variation in cardiovascular risk profile between men and women, in relation to age. Objective: To investigate sex differences in the age-related stiffening of large arteries. Design: Cross-sectional. Methods: One hundred and twenty healthy men and women were recruited and divided equally into tertiles by age: young (mean ± SD, 23 ± 5 years), middle-age (47 ± 3 years) and older (62 ± 7 years). Lipids, mean arterial pressure and heart rate were matched within each tertile. Carotid tonometry and Doppler velocimetry were used to measure indices of large artery stiffness. Results: There was no sex difference in systemic arterial compliance (SAC) in the young group (mean ± SEM, 0.61 ± 0.05 arbitrary compliance units (ACU) in women compared with 0.67 ± 0.04 ACU in men), but in the older population women had lower SAC than men (0.27 ± 0.03 ACU compared with 0.57 ± 0.04 ACU respectively; P < 0.001). Measures independent of aortic geometry (distensibility index and aortic impedance) indicated that stiffness was lower in young women than in men (P < 0.05), but the reverse was true in the older population (P < 0.01). This paralleled the brachial and carotid pulse pressures, which were lower in young (P < 0.01) and higher in older women compared with those in men (P < 0.05). Follicle stimulating hormone concentrations correlated strongly (r values 0.39-0.65) with all indices of central, but not peripheral, arterial function, whereas concentrations of luteinizing hormone, progesterone and oestradiol correlated less strongly. Conclusions: In men and women matched for mean pressures, the age-related stiffening of large arteries is more pronounced in women, which is consistent with changes in female hormonal status.