According to a new study, shorter sleeping times and fragmented sleep are associated with an increased risk of subclinical atherosclerosis. Epidemiological studies had already linked short sleep duration to a higher risk of cardiovascular disease (CVD), but most of these studies relied on self-reported sleep evaluation.

“The aim of this sleep study was to evaluate the association between objective actigraphy-measured sleep parameters and subclinical atherosclerosis using state-of-the-art imaging techniques,” explains lead investigator José Ordovás. A total of 3,974 participants from the PESA CNIC-Santander study — a Spanish observational, prospective cohort on the progression of subclinical CVD — were included in the study. Vascular ultrasonography and cardiac CT were used to assess noncoronary atherosclerosis and coronary calcification, and 7-day actigraphic recording was performed to measure sleep parameters. Four groups were defined according to sleep duration: very short sleep (<6 h), short sleep (6–7 h), reference sleep (7–8 h) and long sleep (>8 h).

After adjustment for traditional risk factors, very short sleep duration was associated with increased atherosclerotic burden compared with the reference group (OR 1.27, 95% CI 1.06–1.52, P = 0.008). Sleep quality was assessed by the total sleep fragmentation index; participants with the most fragmented sleep had the highest risk of multiple affected noncoronary territories compared with the reference group with the least fragmented sleep (OR 1.34, 95% CI 1.09–1.64, P = 0.006). No differences were seen in coronary artery calcification scores between the different sleep groups.

“These significant and robust findings open new areas of research, including investigating whether an increase in the amount and quality of sleep decreases the development of atherosclerosis in people with sleep deficiencies,” concludes Ordovás.