Actigraphy-derived Sleep Efficiency is Associated with Endothelial Function in Men and Women with Untreated Hypertension.

BACKGROUND Poor sleep quality is increasingly recognized as an important and potentially modifiable risk factor for cardiovascular disease (CVD). Impaired endothelial function may be one mechanism underlying the association between poor sleep and CVD risk. The present study examined the relationship between objective measures of sleep quality and endothelial function in a sample of untreated hypertensive adults. METHODS Participants were 127 men (N = 74) and women (N = 53), including 55 African Americans and 72 White Americans, aged 40 to 60 years (mean age, 45.3 ± 8.5 years), with untreated hypertension (SBP 130-159 mm Hg and/or DBP 85-99 mm Hg). Noninvasive brachial artery flow-mediated dilation (FMD) was assessed by ultrasound. Sleep parameters, including sleep efficiency, total sleep time, and subjective sleep quality, were assessed over seven consecutive days by wrist actigraphy. RESULTS Participants averaged 7.76±1 hours in bed, with an average sleep efficiency of 78± 9%, and total sleep time of 6±1 hours. Brachial FMD averaged 3.5±3.1%. In multivariate analyses controlling for sex, race, BMI, clinic BP, income, smoking, alcohol use, and baseline arterial diameter, sleep efficiency was positively associated with FMD (β=.28, p=.012). Subjective sleep quality (β= -.04, p=.63) and total sleep time (β= -.11, p=.25) were unrelated to FMD. CONCLUSION Poor sleep as indicated by low sleep efficiency was associated with impaired FMD. These findings for sleep efficiency are consistent with previous observations of other measures implicating poor sleep as a CVD risk factor. Interventions that improve sleep may also help lower CVD risk.