Potential Racial Disparity In Peripheral Vascular Function Regardless Of Menstrual Cycle Phase

Abstract

African American women (AAW) have the highest rates of cardiovascular disease (CVD) across the lifespan compared to women of other races. Vascular dysfunction is a non-traditional risk factor for CVD and is understudied in AAW. Previous studies have reported fluctuations in vascular function across the menstrual cycle (MC) with the changing levels of estrogen, but this relation has never been explored in the context of race. PURPOSE: To compare nitric oxide-mediated peripheral vascular function across 3 phases of the MC between AAW and CW using passive leg movement (PLM). METHODS: PLM was performed on premenopausal, healthy, female participants not using hormonal contraceptives; 7 AAW (24 ±2 years, BMI: 21.2 ±1.4 kg/m2, BP: 112 ±3/74 ±3 mmHg) and 12 CW (23 ±1 years, BMI: 23.4 ±0.9 kg/m2, BP: 113 ±2/70 ±2 mmHg). Phases of the MC were identified as early follicular (EF) (1-5 days post onset of menstruation; low estrogen), ovulation (OV) (within 1-3 days of luteinizing hormone surge determined by an ovulation test; high estrogen), and mid-luteal (ML) (8-10 days post ovulation; moderate estrogen). Blood velocity and diameter of the femoral artery were measured using Doppler ultrasound. A 2x3 repeated measures ANOVA was used to identify differences in vascular function between AAW and CW across 3 phases of the MC. RESULTS: The overall change in leg blood flow from baseline to peak (mL) was significantly lower among AAW compared to CW across the MC phases. EF (AAW: 195 ±49, CW: 356 ±64), OV (AAW: 156 ±47, CW: 451 ±102) and ML (AAW: 224 ±65, CW: 369 ±41) (p=0.02).The hyperemic response to PLM, calculated as area under the curve (mL), was significantly reduced in AAW compared to CW across the MC phases. EF (AAW: 45 ±21, CW: 131 ±40), OV (AAW: 49 ±28, CW: 144 ±40) and ML (AAW: 67 ±22, CW: 130 ±26) (p=0.03). CONCLUSION: AAW are experiencing an attenuated peripheral vascular response to PLM compared to CW across the menstrual phases. These preliminary data suggest an overall race-derived disparity in peripheral vascular function regardless of MC phase in young premenopausal women.