Sex differences in arterial wave reflection and the role of exogenous and endogenous sex hormones: results of the Berlin Aging Study II

Background: Arterial stiffness is tightly linked to hypertension. Sex differences in hypertension and arterial stiffness have already been established, yet the role of sex hormones is not precisely defined. This study examined age and sex differences of arterial wave reflection and associations with endogenous and exogenous sex hormones in women. Methods: Pulse wave analysis was performed with an oscillometric device in 590 male and 400 female participants of the Berlin Aging Study II. Participants have been recruited from two age-strata, 22-35 years and 60-82 years. Data on exposures and potential confounders, including medication, have been collected at baseline visit. Results: Aumentation index (AIx) and pulse wave velocity increased with age. Mean AIx was higher in women than in men. Multivariable regression analysis showed a positive association between use of oral contraceptive pills (OCPs) and AIx controlling for confounders (age, BMI, current smoking, central blood pressure), with a significantly higher mean AIx in OCP-users compared with nonusers (mean group difference: 4.41; 95% confidence interval 1.61-7.22). Per quartile decrease in estradiol level AIx increased by 1.72 (95% confidence interval 0.43-3.00). In OCP users endogenous estradiol was largely suppressed. Conclusion: The findings suggest important sex differences in measures of arterial wave reflection, with a higher mean AIx observed in women compared with men. OCPs may promote the development of hypertension by increasing AIx. Suppressed endogenous estradiol levels may be responsible for this increased wave reflection due to increased vasotonus of the small and medium arteries.