Objective: Racial differences in cardiovascular mortality among women remain largely unexplained. Preliminary data suggest that African American and Caucasian differences in endothelial function may parallel differential cardiovascular disease (CVD) risk in women. To further study differences in endothelial function between African American and Caucasian women, we analyzed measures of brachial artery flow-mediated dilation (FMD) in women enrolled in the Cardiovascular Health Study (CHS).
Methods and results: Brachial artery FMD was measured in the fasting state using established ultrasound techniques in 1330 Caucasian and 297 African American female participants in CHS (mean age 78.4 +/- 4.4 years). General linear models were used to compare FMD between African American and Caucasian women after adjusting for baseline brachial diameter, hypertension, diabetes, smoking, cholesterol, systolic blood pressure, body mass index, waist/hip ratio, age, education, income level; use of angiotensin-converting enzyme inhibitors, beta-blockers, nitroglycerin, estrogens and lipid-lowering drugs; and presence of clinical or subclinical disease. Adjusted absolute change and percent change in brachial artery diameter was significantly reduced in African American women compared with Caucasian women (P <.0001 and P =.0002, respectively). Similar results were found when the women were stratified by history of CVD (- CVD, P =.02; + CVD, P =.001) and CVD or subclinical vascular disease (- disease, P =.01, + disease, P =.03).
Conclusions: In this cohort, brachial artery FMD was lower in African American women compared to Caucasian women, and this difference persisted after adjustment by multivariable analysis. The increased CVD risk in African American women may be related to impaired endothelial function. It remains to be determined whether African American women may uniquely benefit by interventions designed to improve endothelial health.