Effect of sex, menstrual cycle phase, and monophasic oral contraceptive pill use on local and central arterial stiffness in young adults

Abstract

Arterial stiffness is associated with increased cardiovascular disease risk. Previous sex-based investigations of local and central stiffness report inconsistent findings and have not controlled for menstrual cycle phase in women. There is also evidence that sex hormones influence the vasculature, but their impact on arterial stiffness across a natural menstrual (NAT) or oral contraceptive pill (OCP) cycle has been understudied. This study sought to 1) examine potential sex differences in local and central stiffness, 2) compare stiffness profiles between NAT and OCP cycles, and 3) investigate the relationship between duration of OCP use and arterial stiffness. Sex hormone concentrations, β-stiffness index (local stiffness), and carotid-femoral pulse wave velocity [cfPWV (central stiffness)] were assessed in 53 healthy adults (22 ± 3 yr old, 20 men, 15 NAT women, and 18 OCP women). All participants were tested three times: men on the same day and time 1 wk apart, NAT women in menstrual, midfollicular and luteal phases of the menstrual cycle, and OCP women in placebo, early active and late active pill phases. β-Stiffness was higher in men than NAT and OCP women ( P < 0.001), whereas cfPWV was similar between groups ( P = 0.09). β-Stiffness and cfPWV did not differ across or between NAT and OCP cycles ( P > 0.05 for both) and were not associated with duration of OCP use (β-stiffness: r = 0.003, P = 0.99; cfPWV: r = -0.26, P = 0.30). The apparent sex differences in local, but not central, stiffness highlight the importance of assessing both indexes in comparisons between men and women. Furthermore, fluctuating sex hormone levels do not appear to influence β-stiffness or cfPWV. Therefore, these stiffness indexes may need to be assessed during only one cycle phase in women in future investigations. NEW & NOTEWORTHY We observed higher local, but not central, arterial stiffness in men than women. We also demonstrated that there are no differences in arterial stiffness between naturally cycling women and women who use monophasic oral contraceptive pills, and that the duration of oral contraceptive pill use does not influence arterial stiffness.

Keywords: carotid-femoral pulse wave velocity; menstrual cycle phase; oral contraceptive pill use; sex differences; β-stiffness index.

Fig. 1.

β-Stiffness index (A) and carotid-femoral pulse wave velocity (cfPWV; B) in men, women with natural menstrual cycles (NAT), and women who use oral contraceptive pills (OCPs). Visits 1, 2, and 3 were scheduled weekly in men and during different phases across a single cycle (menstrual, follicular, and luteal phases in NAT women; placebo, early active, and late active phases in OCP women) in women. au, Arbitrary units. Values are means ± SD. No interactions between group and visit or main effects of visit for β-stiffness index or cfPWV were found (P > 0.05 for all). There was a main effect of group for β-stiffness index [*P < 0.001 (men > NAT and OCP)]. There was no main effect of group for cfPWV (P = 0.09).

Fig. 2.

Associations between duration of oral contraceptive pill (OCP) use and β-stiffness index (A) and carotid-femoral pulse wave velocity (cfPWV; B). au, Arbitrary units. No significant correlations between duration of OCP use and local or central arterial stiffness were found (P > 0.05 for both).