Major depressive disorder, anxiety disorders, and cardiac biomarkers in subjects at high risk of obstructive sleep apnea

Objective: Cardiac biomarkers may be valuable when exploring potential mechanisms for the association between cardiovascular disease and psychiatric disorders. In subjects at increased risk for obstructive sleep apnea, we examined whether major depressive disorder (MDD), anxiety disorders, or the combination of these was associated with circulating C-reactive protein (CRP), cardiac troponin T (cTnT), or heart rate variability (HRV). Methods: From the Akershus Sleep Apnea Project, 290 participants were assessed for MDD or any anxiety disorder by a physician using the Structured Clinical Interview for DSM-IV. Fasting blood samples were analyzed with high-sensitivity assays for CRP, cTnT, and HRV calculated from a Holter recording. Age, sex, hypertension, diabetes, hyperlipidemia, obesity, smoking, apnea-hypopnea index, and previous cardiovascular disease were adjusted for. Results: The CRP levels (median [interquartile range], mg/L) were higher in depressive (2.7 [1.1-5.8]) versus nondepressive (1.3 [0.7-3.1], p = .02) and in anxious (2.8 [0.9-5.2]) versus nonanxious (1.3 [0.7-3.1], p = .01). MDD was independently associated with CRP (unstandardized β = 0.387, p = .04), but anxiety was not (unstandardized β = 0.298, p = .09). The CRP level was highest in subjects with comorbid MDD and anxiety (3.4 [1.1-7.8]). The unadjusted and adjusted odds ratios (95% confidence interval) for having measurable cTnT (>3 ng/L) were 0.49 (0.24-1.07) and 0.92 (0.31-2.67) for MDD versus nondepressive and 0.38 (0.18-0.80) and 0.61 (0.30-2.05) for anxiety versus nonanxiety, respectively. HRV did not vary between groups. Conclusions: Although CRP was increased both in MDD and anxiety disorders, patients with comorbid MDD and anxiety may be particularly prone to increased systemic inflammation. Neither MDD nor anxiety disorders were associated with low-level myocardial damage or HRV.