Background: Obstructive sleep apnea (OSA) is associated with coronary risk factors, but it is unknown if OSA is associated with development of coronary disease. We evaluated the association between OSA and the presence of subclinical coronary disease assessed by coronary artery calcification (CAC).
Methods: Consecutive patients with no history of coronary disease who underwent electron-beam CT within 3 years of polysomnography between March 1991 and December 2003 were included. OSA was defined by an apnea-hypopnea index (AHI) ≥ 5 events per hour, and patients were grouped by quartiles of AHI severity. Logistic regression modeled the association between OSA severity and presence of CAC.
Results: There were 202 patients (70% male; median age, 50 years; mean body mass index, 32 kg/m2; 8% diabetic; 9% current smokers; 60% hypercholesterolemic; and 47% hypertensive). OSA was present in 76%. CAC was present in 67% of OSA patients and 31% of non-OSA patients (p < 0.001). Median CAC scores (Agatston units) were 9 in OSA patients and 0 in non-OSA patients (p < 0.001). Median CAC score was higher as OSA severity increased (p for trend by AHI quartile < 0.001). With multivariate adjustment, the odds ratio for CAC increased with OSA severity. Using the first AHI quartile as reference, the adjusted odds ratios for the second, third, and fourth quartiles were 2.1 (p = 0.12), 2.4 (p = 0.06), and 3.3 (p = 0.03), respectively.
Conclusions: In patients without clinical coronary disease, the presence and severity of OSA is independently associated with the presence and extent of CAC. OSA identifies patients at risk for coronary disease and may represent a highly prevalent modifiable risk factor.