Sleep duration and carotid atheromatic burden. Insights from the Corinthia study

Abstract Background Sleep is an essential physiological process and disturbance of sleeping pattern may be associated with cardiovascular risk profile and atheromatosis. Short but also long sleep duration (LSD) may be adversely affect cardiovascular parameters. Purpose To study how sleep duration is associated with cardiovascular risk profile and carotid atherosclerotic burden. Methods Corinthia study is a cross sectional epidemiological study based on 2043 inhabitants (age 40–99 years) of Corinthia region in Greece. Ultrasonography was used to measure intima media thickness (IMT) in the left and right common carotid artery, carotid bulb and internal carotid artery. The mean IMT (meanIMT) were determined as representative values of carotid atherosclerosis burden. Thickness of IMT>1.5 mm or protrusion >50% compared to adjacent segments was considered as atherosclerotic plaque. Based on questionnaires of Corinthia study, total sleeping time per day was recorded. A sleep duration of 7 to 8 h was consider normal (NSD), sleep duration <6 h was consider very short (VSSD), 6–7 h sleep duration was considered short (SSD) and participants with >8 h sleep duration was categorized as LSD. Results Concerning gender more men than women were categorized in the NSD (26% vs. 21%, p<0.001). Subjects in the NSD were also younger compared to subjects categorized in other sleeping patterns (VSSD: 66±12 y vs. SSD: 63±12 y vs. NSD: 62±12 y vs. LSD: 66±12 y, p<0.001), have less prevalence of diabetes mellitus (p<0.05). There was no difference according to sleeping pattern in body mass index, prevalence of hypertension, cardiovascular disease, hyperlipidemia and on current smoking habits according to sleeping patterns. Interestingly, meanIMT (VSSD: 1.08±0.51 mm vs. SSD: 0.97±0.42 mm vs. NSD: 0.97±0.41 mm vs. LSD: 1.14±1.64 mm, p=0.04) and carotid atherosclerotic plaque (VSSD: 35% vs. SSD: 25% vs. NSD: 20% vs. LSD: 30%, p=0.006) was decreased in NSD subjects. Importantly, even after adjustment for the confounders logistic regression analysis revealed that subjects in the NSD group have 50% less odds of carotid atheromatic plaque than subjects in the VSSD (Odds ratio: 0.5, 95% CI 0.28–0.90, p=0.02) (Figure). Conclusion A balanced sleeping pattern with 8h of sleep daily can act as an additive cardioprotective factor in the modern western type societies. Short especially less than 6 hours and long (>8 hours) sleeping duration may act as a cardiovascular risk factor.