Sex differences in noninvasive vascular function in the community

The relation of noninvasive vascular function to sex, sex hormones, and reproductive history in the general population is little understood.

We simultaneously assessed flow-mediated dilation (FMD) and peripheral arterial tonometry in 454 women (mean age 40.4±16.1 years, age range 19-78 years) and 100 men (mean age 44.7±15.3 years) in a community-based cohort. Plasma estradiol, progesterone, luteinizing hormone, and follicle stimulating hormones were measured, and menstrual cycle and reproductive history were recorded.

Vascular function was blunted in men as compared to women irrespective of menopausal status and adjustment for classical cardiovascular risk factors and hormones. Vascular reactivity changed during the menstrual cycle and correlated with estradiol concentrations for FMD, r=0.13 and inversely with progesterone for pulse amplitude, r=-0.14, and brachial artery diameter, r=-0.10. Multivariable-adjusted regressions showed a relation of estradiol with FMD, β 0.658, 95% confidence interval (CI) 0.084/1.232, P=0.025 in women. Age at menarche (β 0.070, 95% CI 0.039/0.101, P<0.0001) and breastfeeding duration (β -0.006, 95% CI -0.011/-0.001, P=0.036) were related to brachial artery diameter, age at menarche also to FMD (β -0.455, 95% CI -0.886/-0.023, P=0.039).

Sex differences in noninvasive conduit and peripheral arterial function with better vascular reactivity in women were not fully explained by female sex hormones and menopausal status. Age at menarche and duration of breastfeeding were also related to vascular function and need further investigation.