Characterizing Vascular and Hormonal Changes in Women Across the Lifespan: A Cross-Sectional Analysis.

Abstract

Introduction: Vascular dysfunction, marked by lower endothelial function and increased aortic stiffness, are non-traditional risk factors that precede the development of CVD. However, the age at which these changes in vascular function occur in women and the degree to which reproductive hormones mediate these changes has not been characterized.

Methods: Women free from major disease were enrolled across the adult lifespan (aged 18-70, n=140). Endothelial function was assessed as flow-mediated dilation (FMD) of the brachial artery during reactive hyperemia using duplex ultrasound and expressed as percent dilation. Aortic stiffness was measured by carotid-femoral pulse wave velocity (cfPWV). Blood samples were obtained to quantify reproductive hormone concentration. Regression models determined age-related breakpoints and mediating factors between age and vascular outcomes.

Results: FMD declined with age with a breakpoint and steeper decline occurring at age 47. Thereafter, age was independently associated with lower FMD (B=-0.13, P<0.001). cfPWV was relatively stable until a breakpoint at age 48, and age was independently associated with higher cfPWV thereafter (B=0.10, P<0.001). Path analysis revealed that the association between age and FMD was partially mediated by follicle stimulating hormone (ab_ind=0.051, P=0.01) and progesterone (ab_ind=0.513, P<0.001) but not estradiol (ab_ind=-0.004, P=0.08). No mediation was present for cfPWV.

Conclusions: Age was associated with endothelial dysfunction and aortic stiffness in women beginning at 47 and 48 years, respectively, 3-4 years prior to the average age of menopause. The association between age and endothelial dysfunction was explained in part by elevations in follicle stimulating hormone and progesterone, but not declining estradiol.