Hypertension becomes more prevalent in women during their postmenopausal years. Nighttime systolic blood pressure (SBP) is especially predictive of adverse cardiac events, and the relationship between rising nighttime SBP and cardiovascular risk increases more rapidly in women compared with men. The reasons for the prognostic significance of nighttime SBP are not completely known but may involve vascular endothelial dysfunction. The purposes of this study were to examine the relationship between nighttime SBP and endothelial function, as assessed by brachial artery flow-mediated dilation (FMD), and to determine whether postmenopausal women with nighttime hypertension (SBP ≥120 mm Hg) evidenced greater endothelial dysfunction compared with women with normal nighttime SBP.
One hundred postmenopausal women (mean [SD] age, 65.8 [7.5] y; mean [SD] body mass index, 28.3 [4.7] kg/m2; hypertension, 47%; coronary artery disease, 51%; mean [SD] clinic SBP, 137  mm Hg; mean [SD] clinic diastolic blood pressure, 67  mm Hg; nighttime hypertension, 34 women) underwent 24-hour ambulatory blood pressure monitoring, actigraphy, and brachial artery FMD assessment.
Multivariate regression models showed that higher nighttime SBP and larger baseline artery diameter were inversely related to FMD. Nighttime SBP and baseline artery diameter accounted for 23% of the variance in FMD. After adjustment for baseline artery diameter, women with nighttime hypertension had lower mean (SD) FMD than women with normal nighttime SBP (2.95% [0.65%] vs 5.52% [0.46%], P = 0.002).
Nighttime hypertension is associated with reduced endothelial function in postmenopausal women. Research examining the therapeutic benefits of nighttime hypertension treatment on endothelial function and future cardiovascular risk in postmenopausal women is warranted.
From the 1Nell Hodgson Woodruff School of Nursing, Emory University, Atlanta, GA; 2Duke University Medical Center, Durham, NC; 3University of North Carolina, Chapel Hill, NC; and 4College of Nursing, Florida State University, Tallahassee, FL.
Received August 29, 2014; revised and accepted October 29, 2014.
Funding/support: This study was supported by the National Institute of Nursing Research, National Institutes of Health (Bethesda, MD; grant NR05281) and the National Center for Research Resources, Clinical Research Centers Program, National Institutes of Health (grant MO1-RR-30).
Financial disclosure/conflicts of interest: A.S. is a member of the SunTech Medical Advisory Board.
Address correspondence to: Andrew Sherwood, PhD, Box 3119, Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710. E-mail: email@example.com