A Case Study: The Effect of Hormone Therapy on Vascular Function in a Male-to-Female Transgender Endurance Athlete

Abstract

The aim of this case study was to assess vascular function in a 27-year-old male-to-female transgender endurance athlete before hormone therapy and during treatment with gender affirming hormone therapy (GAHT) in an effort to better understand the effects of estrogen therapy and testosterone blockade on male vascular physiology. Testing occurred at 4-8 week intervals for 19 months. At each visit, testing included measurement of blood hormone levels including free testosterone, total testosterone and estradiol, resting heart rate and blood pressure, non-invasive central blood pressure measurements, pulse wave velocity (PWV), ultrasound quantified arterial flow mediated dilation (FMD), and dual-energy x-ray absorptiometry (DEXA) scans. These data were analyzed over time to observe gross trends and then analyzed for correlation. Visceral body fat measured remained unchanged from baseline after 15 months gender affirming hormone therapy. Systolic and diastolic blood pressures increased throughout treatment and systolic pressures were positively correlated with time. PWV showed signs of decreasing arterial stiffness after initiation of GAHT, but returned to baseline by the end of the study. FMD trended downwards initially with GAHT, indicating reduced vascular reactivity, but returned towards baseline following sustained treatment with GAHT. More research is needed to examine the long-term effects of gender affirming hormone therapy on vascular function, blood pressure, and vascular stiffness.