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.