Obstructive sleep apnea (OSA) is associated with increased cardiovascular risk. Stress imposed on the myocardium by repeated severe hypoxemia and/or BP surges during sleep may result in subclinical myocardial injury. A high-sensitivity cardiac troponin T (hs-cTnT) assay has been developed. We hypothesized that the severity of OSA, as assessed by the apnea-hypopnea index (AHI), is associated with circulating levels of hs-cTnT in the general population.
Five hundred five subjects drawn from the general population (age range, 30-65 years; 45% women) underwent in-hospital polysomnography and had morning blood samples drawn. Oversampling of subjects at high risk of OSA was performed.
Overall, hs-cTnT was detectable (≥ 3 ng/L) in 216 subjects (42.8%). After categorizing subjects according to AHI cutoffs that correspond to no, mild to moderate, and severe OSA, the proportion of subjects with detectable hs-cTnT levels increased with increasing severity of OSA (P for trend < .001). Multivariate logistic regression with detectable hs-cTnT as the dependent variable was used to further assess the association between OSA and troponin T. After adjustment for significant univariate predictors of detectable hs-cTnT, the association between AHI and hs-cTnT was no longer statistically significant.
The prevalence of detectable hs-cTnT increases in proportion to OSA severity, but this association is likely to be caused by a clustering of cardiovascular risk factors among subjects with OSA.