The Impact of Race on Vascular Health in Women with Breast Cancer

Background: Cardiovascular disease (CVD) is a leading cause of death in women with breast cancer. In addition, non-Hispanic Black (NHB) women with breast cancer experience worse CVD-related mortality compared to their non-Hispanic White (NHW) counterparts. Although the reason for this racial disparity remains unclear, differences in vascular health may play a role. Thus, the purpose of this study was to comprehensively assess cardiovascular health in NHB and NHW women with breast cancer. Methods: Forty-five women (25 NHW, 20 NHB) with a clinical diagnosis of breast cancer (AJCC stages 0-3) within two years from diagnosis participated in this study. Flow-mediated dilation (FMD) was performed to represent conduit-vessel vascular endothelial function. Cutaneous post occlusive reactive hyperemia (PORH) with local thermal heating (LTH) and iontophoresis of acetylcholine (Ach) were performed to represent various mechanisms regulating microvascular function. Pulse wave velocity (PWV) and pulse wave analysis (PWA) were performed to assess central and aortic stiffness, respectively. Maximal exercise testing (VO 2 max) was performed to assess cardiorespiratory fitness. NIRS was used to assess skeletal muscle oxidative capacity (SMOC). Allostatic load was calculated as a composite of social determinants of health (SDOH). Data are reported as mean ± SD. Results: The average time from breast cancer diagnosis was 6±5 months. No racial differences ( p =0.897) were observed in the proportion of NHW and NHB women undergoing chemotherapy (45% vs. 55%, respectively). Breast cancer stage was also similar ( p =0.382) between groups with the distribution across stages as follows: 31.1% at Stage 0 (64% NHW, 36% NHB), 40.0% at Stage 1 (56% NHW, 44% NHB), 24.4% at Stage 2 (46% NHW, 54% NHB), and 4.4% at Stage 3 (50% NHW, 50% NHB). NHW women (59±12 years) were 6 years older ( p =0.090) compared to NHB women (53±12 years), and no differences in BMI, clinical laboratory values, or allostatic load were observed between groups (all p >0.05). PORH ( p <0.001), LTH ( p <0.001), and Ach ( p =0.033) were all higher in NHW compared to NHB and remained significant after controlling for stage ( p <0.05) and presence of chemotherapy ( p <0.05). No differences in FMD ( p =0.555), PWV ( p =0.270), PWA ( p =0.992), VO 2 max ( p =0.565) or SMOC ( p =0.763) were observed between groups. Conclusion: The results of the current study provide evidence that NHB women with breast cancer exhibit lower microvascular function compared to their NHW counterparts. Importantly, SDOH, cancer stage, and presence of chemotherapy were similar between groups and did not impact the findings. Given that NHB women were 6 years younger, differences in microvascular function between groups may provide mechanistic insight into the racial disparity in CVD risk following breast cancer diagnosis. This work was supported by American Heart Association SFRN 863621 (RAH, AG, NLW) This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.