Background: The impact of obstructive sleep apnea (OSA) on the development of atherosclerotic cardiovascular disease (CVD) in the absence of overt CVD or risk factors is unclear. Our purpose was to assess whether patients with OSA without overt CVD or risk factors have subclinical atherosclerosis as evaluated by carotid intima medial thickness (CIMT) compared to matched controls.
Methods: We measured CIMT in patients >40 years old, who underwent polysomnography for suspected OSA and did not have a history of CVD or risk factors (smoking, hypertension, diabetes, hyperlipidemia). OSA severity was classified according to apnea-hypopnea index. Serum levels of high-sensitivity C-reactive protein, fibrinogen, and lipids were assessed and relationships with OSA severity explored. CIMT measurements from patients with OSA were compared those of to age-, gender-, and BMI-matched controls from a community-based cohort without known CVD or OSA.
Results: Fifty-one patients were studied. Of these, patients with severe OSA had an increased CIMT compared to patients without OSA, but the relationship was not significant after controlling for age (p = 0.10). However, 37 patients had OSA and were matched to 105 controls. CIMT was significantly increased in OSA patients versus controls (0.77 vs. 0.68 mm, p = 0.03). The difference between patients and controls was greater for patients with severe OSA (0.83 vs. 0.71 mm) than for patients with mild-to-moderate OSA (0.71 vs. 0.67 mm).
Conclusions: Patients with OSA but without a history of or risk factors for CVD have increased CIMT compared to a BMI-, age-, and gender-matched cohort. This provides evidence that OSA is an independent risk factor for the development of CVD.