Sleeping less than 6 hours a night could raise risk for atherosclerosis

Sleeping less than six hours a night or experiencing poor-quality rest has been independently linked to an increased risk of subclinical multiterritory atherosclerosis, a team of Spanish researchers reported in the Journal of the American College of Cardiology Jan. 14.

“Sleep is an essential physiological process that protects our physical and mental health,” Fernando Dominguez, MD, PhD, and coauthors wrote in the journal. “Sleep deficiency is highly prevalent in Western societies, and epidemiological studies suggest that not only short but also long sleep duration is related to an increased cardiovascular risk.”

Sleep quality and duration have been tied to coronary heart disease, stroke and subclinical atherosclerosis in the past, the authors said, but most studies rely on self-reported questionnaires for data about patients’ sleep patterns and haven’t employed any of the updated, more advanced technologies for accurately measuring atherosclerosis.

Dominguez and his team, which included JACC editor-in-chief Valentin Fuster, MD, PhD, obtained seven-day actigraphic recording data from 3,974 patients enrolled in the PESA (Progression of Early Subclinical Atherosclerosis) study in an effort to link actigraphy-measured sleep parameters with subclinical atherosclerosis. The population was middle-aged and comprised mostly of men.

The researchers divided subjects into four groups: those who had very short sleep duration (less than 6 hours), short sleep duration (6 to 7 hours), reference sleep duration (7 to 8 hours) and long sleep duration (more than 8 hours). Carotid and femoral 3D vascular ultrasound and cardiac CT were used to quantify coronary calcification and noncoronary atherosclerosis.

After adjusting for conventional risk factors, Dominguez et al. reported “very short” sleep duration was independently associated with a 27 percent higher risk of atherosclerosis throughout the body. Patients in the highest quintile of sleep fragmentation were similarly affected, presenting with 34 percent higher prevalence of multiple affected noncoronary territories than a control group. The team didn’t find any differences in coronary artery calcification based on sleep duration.

“The study by Dominguez et al. extends the published reports on sleep duration and vascular disease to an early middle-aged cohort by using an objective measure of sleep duration and sensitive measures of atherosclerosis in multiple vascular territories,” Daniel J. Gottlieb, MD, MPH, and Deepak L. Bhatt, MD, MPH, wrote in a related JACC editorial. “Unfortunately, the study sheds little light on the potential mechanisms underlying the relation of sleep to vascular disease.”

Gottlieb and Bhatt said the study missed an opportunity to study blood pressure and glucose metabolism more closely, since both acute and chronic sleep deprivation have been associated with hypertension and diabetes mellitus and those conditions were more common in the study cohort that got the least amount of sleep.

“Neither blood pressure nor glucose metabolism was assessed with sufficiently comprehensive measures to explore these factors as potential effect mediators,” they wrote. “More importantly, the causes of short sleep duration and sleep fragmentation in this cohort are unknown.”