Abstract 15398: Symptoms of Insomnia are Associated with Reduced Endothelial Function

Abstract

Background: Recent studies link insomnia with increased risk of hypertension, myocardial infarction, and mortality. Endothelial function may be a mechanism by which insomnia affects cardiovascular (CV) health. We hypothesized that insomnia is associated with impaired endothelial function.

Methods: Working adults (n=534) enrolled in the Emory-Georgia Tech Predictive Health Institute study, a large prevention initiative and registry, completed demographic, clinical, depression (Beck Depression Inventory-II; BDI-II), sleep and noninvasive endothelial function (brachial artery flow-mediated dilation; FMD) measures at baseline. Insomnia symptoms, derived from the Pittsburg Sleep Quality Index, were defined as 1 or more of the following: sleep latency of ≥30 minutes, nighttime or early morning awakenings, sleep medication use ≥3 times per week during the past month. FMD was defined as the percent change from baseline artery diameter.

Results: The sample was 68% female, 21% African American, mean age of 48±11 years, mean body mass index (BMI) 27.6±6.3 kg/m², mean blood pressure 120±15/76±10mmHg and mean FMD 6.9±4.2%. Hypertension, diabetes mellitus and smoking were present in 21%, 7.1% and 4.8% of the sample, respectively. Participants reporting insomnia symptoms (n=211) had decreased FMD response (6.4±4.2% vs 7.2±4.1%, p=.037), shorter sleep duration (6.4±1.0 hours vs 6.8±0.9 hours, p<.001) and greater BDI-II scores (6.8±5.8 vs 4.4±4.9, p<.001) than those without insomnia (n=323). In multivariate analysis, presence of insomnia was inversely associated with FMD (parameter estimate ± S.E.= -0.76±0.33, p=.02, adjusted R²=.22) adjusting for baseline artery diameter, age, gender and baseline artery diameter-by-insomnia interaction. The association between insomnia and FMD (parameter estimate ± S.E.= -0.81±0.36, p=.02, adjusted R²=.22) remained after further adjustment for ethnicity, smoking, BMI, hypertension, diabetes, heart rate, glucose, lipid profile, self-reported sleep duration, BDI-II scores, and CV and antidepressant medications.

Conclusion: Insomnia was associated with reduced endothelial function. Impaired endothelial function may contribute to greater CV risk in people who report insomnia symptoms.