Sleep Apnea and the Impacts on Diabetes

Low Oxygen Levels May Trigger Stress Hormone Changes

Obstructive sleep apnea (OSA) can have significant and unexpected effects on our overall health. In particular, it has a clear impact on the risk of developing and worsening diabetes. Learn about the relationship between sleep apnea and diabetes and how treatment might help you to control your blood sugars.

What Is Sleep Apnea?

Obstructive sleep apnea is characterized by repeated collapses of the upper airway during sleep.

These events are associated with drops in the oxygen levels of the blood and fragmentation of sleep. Blockage of the airway typically occurs due to collapse of soft tissues in the throat, including the soft palate and tongue. It may be exacerbated by factors like being overweight or obese, sleeping on the back, consuming alcohol near bedtime, and by REM sleep.

The severity of sleep apnea is determined with a sleep study and is based on a measurement of the number of breathing disturbances per hour called the apnea-hypopnea index (AHI). The ranges include:

  • Normal: AHI <5
  • Mild OSA: AHI 5-15
  • Moderate OSA: AHI 15-30
  • Severe OSA: AHI >30

The condition has numerous symptoms and is often associated with snoring and daytime sleepiness. It may also have health consequences, including impacts on heart health.

How Does Sleep Apnea Contribute to Diabetes?

It is believed that the drops in the oxygen levels of the blood that occur with sleep apnea contribute to the development and worsening of diabetes.

This is called hypoxemia. When blood oxygen levels drop below 90%, this is considered abnormal. These drops, called desaturations, may lead to stress in the body.

As a result of the plummeting oxygen levels, the brain realizes that the airway is compromised. In response, a burst of stress hormone called cortisol is released.

This triggers an awakening to resume normal breathing, but it can also have other effects. The release of cortisol and other catecholamines with the episodes may increase insulin resistance. Resulting sleep deprivation may further exacerbate these changes.

Studies show that sleep apnea is strongly correlated with the risk of having diabetes. It is correlated with insulin resistance and glucose intolerance, two markers of diabetes, independent of body mass index (BMI). This means that regardless of weight, sleep apnea makes diabetes more likely. Controlling for other variables, the incidence of diabetes doubles when the apnea-hypopnea index (AHI) is greater than 5, consistent with a diagnosis of at least mild sleep apnea. This seems to worsen the more oxygen levels drop in the night.

When sleep apnea is moderate to severe, the prevalence of diabetes is 15% of people, compared to just 3% of those with normal breathing in sleep.

Can Treating Sleep Apnea Improve Diabetes Control?

The good news is treating sleep apnea can reduce your risk of developing or worsening diabetes, especially if your condition is moderate to severe with significant oxygen desaturations.

In fact, continuous positive airway pressure (CPAP) has been shown to decrease the 3-month average of blood glucose called the hemoglobin A1c from 7.8% to 7.3% among people with severe sleep apnea.

Therefore, if you have diabetes, it is recommended that you also have your sleep evaluated by a sleep specialist to ensure that you don’t have sleep apnea contributing to your condition. If you do have it, effective treatment may improve your diabetes and prevent other detriments to your health.

Sources:

Collop, N. “The effect of obstructive sleep apnea on chronic medical disorders.” Cleveland Clinic Journal of Medicine. 2007;74(1):72-78.

Hassaballa, HA et al. “The effect of continuous positive airway pressure on glucose control in diabetic patients with severe obstructive sleep apnea.” Sleep Breathing. 2005;9:176-180.

Kryger, MH et al. "Principles and Practice of Sleep Medicine." Elsevier. 5th edition. 2011.

O’Connor, GT et al. “Prospective study of sleep-disordered breathing and hypertension: the Sleep Heart Health Study.” Am J Respir Crit Care Med. 2009;179:1159-1164.

Prinz, P. “Sleep, Appetite, and Obesity–What is the Link?” Public Library of Science and Medicine. December 2004. 1:186-188.

Spiegel, K. “Impact of sleep debt on metabolic and endocrine function.” The Lancet. October 23, 1999. 354:1435-1439.

Taheri, S. “Sleep and metabolism: Bringing pieces of the jigsaw together.” Sleep Medicine Reviews. 2007. 11:159-162.

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