Linking sleep apnea and heart disease

A new study by researchers from the Brigham and Women’s Hospital in Boston has shown that obstructive sleep apnea (a condition in which sufferers stop breathing while asleep) is associated with markers of cardiovascular disease, indicating some subclinical damage to the heart.

Obstructive sleep apnea, or OSA, is caused by a blockage to the upper airway which prevents breathing for a few seconds at a time while asleep. Often accompanied by snoring, many people get temporary OSA after infection or drinking alcohol that relaxes body tone. The main symptom is excessive daytime sleepiness, but it can cause more severe problems.

OSA has previously been linked to cardiovascular disease, but because there are so many other risk factors for cardiovascular disease, a causal link has been elusive. The new study followed 1,645 older participants study for around 12 years and found an association between OSA and levels of high sensitivity troponin T (hs-TnT). Higher levels of hsTnT are known to predict both coronary heart disease and heart failure, so indicate damage to the heart.

The researchers found that this connection between OSA and high hs-TnT levels remained after controlling for other factors such as age, gender, BMI, smoking, diabetes, alcohol, cholesterol and blood pressure. hs-TnT levels was significantly predicted higher risk of death or heart failure across all OSA severities, with the relationship strongest in those whose OSA was most severe.

However, these results should be treated with caution since the design was correlational, so it is difficult to make causal inferences, and there were not that many participants with severe OSA. But nevertheless, it does suggest that monitoring hs-TnT levels in OSA patients could be used to assess their risk of cardiovascular problems.

http://www.eurekalert.org/pub_releases/2013-10/ats-sai102213.php