Sleep apnea and progression of coronary artery calcium: the multi-ethnic study of atherosclerosis

Abstract

Background: Obstructive sleep apnea (OSA) is a common condition believed to be linked to cardiovascular comorbidities. Its potential effect on progression of subclinical atherosclerosis is not well studied. We tested the hypothesis that OSA is associated with progression of coronary artery calcium (CAC) score. We also evaluated whether traditional cardiovascular risk factors mediated the association. Methods: The Multi-Ethnic Study of Atherosclerosis (MESA) is a prospective epidemiologic cohort which has had a total of 5 clinic visits. Our primary analytic sample included 2,603 participants who at or near visit 2 (2002-2004) completed a sleep questionnaire and underwent coronary computerized tomography (CT), and underwent a repeat coronary CT approximately 8 years later (Visit 5: 2010-2011). Participants were categorized by their self-reported sleep breathing history: OSA: n= 102; Habitual snore: n = 666; Normal: n= 1835. mean age: 61.2).Results: Absolute CAC scores varied at visit 2, with the highest CAC prevalence among those with OSA, and lower but similar CAC prevalences among those who were habitual snorers or normal. Over 8 years of follow-up, greater progression of CAC was observed among those with OSA vs. those classified as normal (mean increase of 227.7 vs.135.6 Agatston units). This difference persisted after adjustment for BMI but was not significant after adjustment for cardiovascular risk factors (138.2 vs. 185.9 Agatston units; p = 0.08). CAC progression among habitual snorers was similar to that observed in the normal group.Conclusion: Self-reported sleep apnea was associated with CAC score progression after adjustment for demographics, behaviors and BMI. However, the association was not significant after accounting for cardiovascular risk factors which may mediate the association between OSA and CAC.