Sleep apnea, coronary artery calcium density, and cardiovascular events: Results from the Multi-Ethnic Study of Atherosclerosis

Study Objectives: Evaluate the association between obstructive sleep apnea (OSA), coronary artery calcium (CAC) density, and cardiovascular events in the Multi- Ethnic Study of Atherosclerosis (MESA). Methods:We analyzed 1,041 participants with nonzero CAC scores who had polysomnography and CAC density data from the fifth examination of the Multi-Ethnic Study of Atherosclerosis. OSA was defined as apnea-hypopnea index ≥ 15 events/h. Multivariable linear regression models were used to evaluate the independent associationbetweenOSAandCACdensity. Additionally,weevaluatedtheimpact ofOSAonassociations ofCACmeasureswith incident cardiovasculardisease events by testing for interaction in Cox proportional hazard regression models. Results: Our analytical sample was 45% female with a mean age of 70.6 +/29 years. Of this sample, 36.7% (n = 383/1041) had OSA (apnea-hypopnea index ≥ 15 events/h). OSA was inversely and weakly associated with CAC density (b = -0.09; 95% CI, -0.17 to -0.02; P = .014) and remained significantly associated after controlling for traditional cardiovascular risk factors (b= -0.08;95%CI, -0.16 to 0;P= .043). However, this inverse association was attenuated after controlling for body massindex (b= -0.05;95%CI, -0.13 to 0.02;P= .174). Themeanfollow-up period for cardiovascular disease events was 13.3 +/22.8 years. Additionally, exploratory analysis demonstrated that CAC density was independently and inversely associated with cardiovascular disease events only in the non-OSA subgroup (apneahypopnea index ≤ 15 events/h) (hazard ratio, 0.509; 95% CI, 0.323-0.801); P = .0035). Conclusions: OSAwas associated with lower CAC density, but this association was attenuated by body mass index. Further, increased CAC density was associated with a reduced risk of cardiovascular disease events only in individuals within the non-OSA group in exploratory analysis.