Obstructive Sleep Apnea: Obnoxious Sleep Disorder or Dangerous Risk Factor for Cardiovascular Disease?

Obstructive Sleep Apnea, or OSA, is a common sleep disorder that affects millions of people worldwide. It occurs when the muscles at the back of the throat fail to keep the airway open during sleep, causing repeated pauses in breathing that result in drops in blood oxygen levels. OSA can lead to daytime fatigue, reduced productivity and higher risk of accidents. However, the consequences of OSA extend far beyond these seemingly annoying immediate effects, and research has shown that untreated OSA can have serious long-term health implications.

One of the most glaring and concerning connections is between untreated sleep apnea and insulin resistance or Type 2 Diabetes (T2DM). Studies have found that individuals with OSA are at a higher risk for developing Type 2 Diabetes, and that those who already have insulin resistance or Diabetes are more likely to have uncontrolled blood sugar levels if they have a co-morbidity of OSA. The repeated drops in oxygen levels overnight, as well as sleep disruption, leads to worsening insulin resistance, which we know is the driver of Type 2 Diabetes development.

Another concerning link exists between untreated OSA and cardiovascular disease. Sleep Apnea has been shown to increase risk of hypertension, heart rate variability, atherosclerosis and stroke. The repeated surges of adrenaline and other stress hormones during interrupted sleep due to sleep apnea places strain on the cardiovascular system and increases inflammation and oxidative stress (OS), leading to the development of atherosclerotic plaque buildup in the arteries. This relationship is highlighted even further by demonstration of reduced inflammatory markers in patients with diagnosed sleep apnea after treatment with an oral appliance.

Many consider obesity to be a risk factor for OSA, but in fact, the link between sleep apnea and obesity is bidirectional, with OSA also contributing to weight gain. While excess weight can lead to increased fat deposits around the airway, the connection between OSA and insulin resistance also contributes to weight gain and weight that is challenging to lose. 

Obstructive sleep apnea is also closely linked to the common condition hypertension (or high blood pressure), which itself is another major risk factor for heart disease and stroke. The repeated drops in oxygen levels due to pauses in breathing can lead to repeated surges in blood pressure, causing further oxidative stress and risk for atherosclerotic disease.

In looking at the connections between OSA and insulin resistance, Type 2 Diabetes, cardiovascular disease and hypertension, it is clear that OSA represents a major root cause for arterial disease. Fortunately, OSA is treatable, and effective management can have a significant impact on reducing the risk of these known drivers of cardiovascular disease. Continuous Positive Airway Pressure (or CPAP) therapy is generally the most common treatment for OSA, but in many cases individuals can work with their dental team to fashion an oral appliance that may be equally as effective. 

Of note, this article has focused on the causes and effects of Obstructive Sleep Apnea, but this is not the only type of sleep apnea. Central Sleep Apnea (CSA) is a distinct disease process that can co-occur with OSA or present on its own. While OSA is caused by a physical obstruction of airflow during sleep, CSA is a more heterogeneous condition, often resulting from underlying disease processes or even use of medications (such as opioids) that decrease respiratory drive. CSA requires a sleep study for diagnosis as well, but treatment modalities may be different based on etiology. 

If you, or someone you love, have symptoms of OSA, including pauses in breathing during sleep, loud snoring, daytime fatigue or drowsiness, it is vital that you seek medical care to be tested for OSA and determine an optimal treatment regimen. While the immediate effects of OSA can be obnoxious, the long-term effects can have a serious and negative impact on cardiovascular health. Stay healthy, and sleep well my friends!