Chronically Disrupted Sleep Might Increase Heart Disease Risk

Sleep irregularity, and sleep duration (SD) irregularity in particular, was linked with several measures of subclinical (ie, without signs and symptoms) atherosclerosis, or heart disease, according to a novel study of an ethnically diverse and older adult population published in the Journal of the American Heart Association.

Past research has shown irregular sleep has been associated with cardiovascular disease (CVD), but less is known about the links between sleep regularity and atherosclerosis. The presence of previous evidence suggested that adults with abnormal sleep characteristics are more likely to have significant subclinical atherosclerosis, the authors noted.

They analyzed cross-sectional associations of actigraphy-assessed sleep duration and sleep timing regularity with subclinical atherosclerosis in the community-based MESA (Multi-Ethnic Study of Atherosclerosis).

The MESA Sleep Ancillary Study recruited 2032 participants (mean age, 68.6 ± 9.2 years; 37.9% White) who finished a 7-day wrist actigraphy. The participants were racially and ethnically diverse, including participants who identified as White, Black, Hispanic American, or Chinese American.

Next, coronary artery calcium (CAC), carotid plaque presence, carotid intima-media thickness, and the ankle-brachial index (ABI) were measured in participants. The models were adjusted for demographics, CVD risk factors, and other sleep characteristics like sleep duration (SD).

Compared with participants with more regular SDs of ≤ 60 minutes, after adjusting for demographics, lifestyle characteristics, and body mass index, participants with more SD irregularity (SD > 120 minutes) were more likely to have high CAC burden (> 300; prevalence ratio, 1.33 [95% CI, 1.03 to 1.71]) and abnormal ABI (< 0.9; prevalence ratio, 1.75 [95% CI, 1.03 to 2.95]). Participants with irregular sleep timing (SD > 90 minutes) were more likely to have high coronary calcium burden (prevalence ratio, 1.39 [95% CI, 1.07 to 1.82]), compared with participants with more regular sleep timing (SD ≤ 30 minutes).

These links continued even after cardiovascular risk disease factors, average sleep duration, obstructive sleep apnea, and sleep fragmentation were adjusted. Researchers saw an association between more sleep timing irregularity and high CAC burden, but not with other measures of subclinical CVD. These findings suggest that sleep regularity might have a unique etiologic link to subclinical CVD, and researchers highlighted this multiple times throughout the study.

“While it is common for sleep patterns to change as adults age,the proportion of the general population with irregular sleep patterns, who are not shift workers, may be concerninggiven the growing evidence linking sleep irregularitywith CVD risk,” they wrote.

The authors hypothesized that these links are because of circadian disruption that can affect cardiovascular function, which is also supported by previous studies.

“Almost all major cardiovascular functions, including heart rate, blood pressure, vascular tone, and endothelial functions, are regulated by circadian clock genes,” they wrote. “Disruption or misalignment of circadian rhythms can interrupt these important cardiovascular functions, resulting in the promotion of chronic inflammation, alterations in glucose metabolism, heightened sympathetic nervous system activation, and increases in arterial pressures, all predisposing to the risk of atherosclerosis progression.”

Since atherosclerosis can take time to develop, there is time for intervention. The encouragement of regular sleep schedules might be an important part of clinical lifestyle recommendations to help prevent heart disease. The authors’ findings also suggest that sleep hygiene recommendations also might be useful as a cardiovascular health promotional strategy. They also underscore the importance of clinical trials and testing the role of sleep interventions to improve sleep duration as a lifestyle component for CVD risk reduction.

This study is one of the first to show evidence that irregular sleep duration and timing are linked to measures of subclinical atherosclerosis. However, more research is needed to better understand how sleep development plays a role in CVD, the authors noted.

Since this study is cross sectional and observational, inferences about causality need to be confirmed in future studies, but researchers say these novel results support further study of sleep regularity in other samples with prospective assessment of CVD risk.

Reference

Full KM, Huang T, Shah NA, et al. Sleep irregularity and subclinical markers of cardiovascular disease: the multi-ethnic study of atherosclerosis. J Am Heart Assoc. Published online February 15, 2023. doi:10.1161/JAHA.122.027361