The severity of obstructive sleep apnea (OSA) in the general population is independently associated with subclinical systemic atherosclerosis, which highlights the potential importance of severe OSA as a possible predictive factor for cardiovascular disease, according to study results published in the European Respiratory Journal.

Untreated OSA can potentially increase patients’ cardiovascular disease burden by accelerating atherosclerosis. This cross-sectional study was performed using data from a population-based cohort of Korean men and women between the ages of 39 and 70 (N=2157), who were all participants in the ongoing prospective investigation, the Korean Genome and Epidemiology Study (KoGES). All participants were free of structural heart disease and underwent overnight in-home polysomnography and chest computed tomography. The study was designed to evaluate the associations between objectively measured OSA severity and the presence of subclinical systemic atherosclerosis. Atherosclerosis was identified using noninvasive measurements, including tomographic quantification of calcium burden, which was measured by the Agatston score.

Participants were divided into 3 groups based on OSA severity: no OSA (apnea-hypopnea index [AHI] <5; n=1096), mild OSA (AHI ≥5 but <15; n=700), and moderate to severe OSA (AHI ≥15; n=361). Moderate to severe OSA was associated with ascending thoracic aorta calcification (aTAC; ≥100 units) using univariate logistic regression (odds ratio [OR], 2.70; 95% CI, 2.10-3.47; P <.001). After adjusting for cardiovascular risk factors in the multivariate analyses, moderate to severe OSA remained independently associated with aTAC (OR, 1.59; 95% CI, 1.18-2.15; P =.002).

Furthermore, the association between moderate to severe OSA and aTAC among participants with higher epicardial fat volume (EFV) was slightly stronger than among participants without OSA and lower EFV tertile after adjusting for cardiovascular risk factors (OR, 2.11; 95% CI, 1.30-3.43; P =.003), with a moderate effect by EFV tertiles (P for interaction <.001).  

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Because this was a cross-sectional study, causal relationships remain to be identified in future research. Study investigators concluded that the “…results support the finding that severity of OSA in general participants without structural heart disease is independently associated with subclinical systemic atherosclerosis. Multiple comorbid cardio-metabolic disorders of patients with OSA, especially in [individuals] with more epicardial fat, must be taken into consideration when investigating OSA-associated cardiovascular risk and systemic atherosclerosis. The challenges for future perspectives are in the development of specific preventive strategies targeting the pathways of cardiovascular calcification induced by severe intermittent hypoxia.”

Reference

Kim S, Lee KY, Kim NH, et al. Relationship of obstructive sleep apnoea severity and subclinical systemic atherosclerosis [published online October 31, 2019]. Eur Respir J. doi:10.1183/13993003.00959-2019