Sleep duration and vascular inflammation using hybrid positron emission tomography/magnetic resonance imaging: Results from the Multi-Ethnic Study of Atherosclerosis

Study Objectives: Short sleep duration (SD) is associated with cardiovascular disease. We investigated the relationship between objective SD and subclinical atherosclerosis employing hybrid positron emission tomography/magnetic resonance imaging with 18F-FDG tracer in the MESA cohort. Methods:WeutilizeddatafromMulti-Ethnic Study ofAtherosclerosis-SLEEPandMulti-EthnicStudyof Atherosclerosis-PETancillary studies.SDandsleepfragmentation index (SFI) were assessed using 7-day actigraphy. The primary and secondary outcomes were carotid inflammation, defined using target-to-background ratios, and measuresofcarotidwall remodeling(carotidwall thickness),summarizedbySDcategory.Multivariable linear regressionwasperformedtoassesstheassociationbetween SD and SFI with the primary/secondary outcomes, adjusting for several covariates including apnea-hypopnea index, and cardiovascular disease risk. Results: Our analytical sample (n = 58) was62%female (mean age 68±8.4 years). AverageSDwas 5.1±0.9 hours in the shortSDgroup (≤6 h/night, 31%), and 7.1± 0.8 hours in the normal SD group (69%). Prevalence of pathologic vascular inflammation (maximal target-to-background ratio > 1.6) was higher in the short SD group (89%vs53%,P=.01).Thosewith shortSDhadahighermaximaltarget-to-background ratio (1.77 vs 1.71), although thiswasnot statistically significant (P=.39). Carotid wall thickness was positively associated with SFI even after adjusting for covariates (Beta [standard error] = 0.073 ± [0.032], P = .03). Conclusions: Prevalence of pathologic vascular inflammation was higheramongthosewhoslept≤6 hours, and vascular inflammationwas higheramongthose with a SD of ≤ 6 hours. Interestingly, SFI was positively associated with carotid wall thickness even after adjustment for covariates. Our results are hypothesis generating but suggest that both habitual SD and SFI should be investigated in future studies as potential risk factors for subclinical atherosclerosis.