Sleep Apnea and Diabetes: What’s the Connection?

Sleep apnea is more than disruptive snoring. It’s severely restricted airflow during sleep, sometimes several times a night. If not treated, this sleep-related breathing problem can cause serious issues. These include memory loss, heart failure, stroke, and diseases like diabetes. In fact, adults with obstructive sleep apnea (OSA) are more likely to develop type 2 diabetes, and more than half of type 2 diabetes patients suffer from OSA.

What’s the connection between these two conditions? If you have type 2 diabetes, are you at risk for developing OSA? How can you reduce your risk for both of these conditions and the cardiovascular complications they can trigger?

How does sleep apnea affect the heart?

When your breathing periodically stops throughout the night, it causes the oxygen levels in your tissues to drop (hypoxia). This can lead to confusion, restlessness, difficulty breathing and bluish skin. Frequent episodes of hypoxia can damage the heart’s blood vessels, increase the heart rate and raise blood pressure. Over time, this cardiovascular stress can enlarge the heart.

“Sleep apnea not only affects the quality of sleep, it may also activate the sympathetic nervous system,” says Ron Varghese, M.D., an endocrinologist with the University of Miami Health System. “Due to sleep fragmentation and intermittent hypoxia, OSA may also cause patients to not get the normal nocturnal dip in cortisol levels during sleep. These factors are known to increase cardiovascular risk.”

Sleep apnea, diabetes, insulin resistance and obesity are all connected.

When the body’s cells don’t respond normally to insulin (the hormone that helps control the amount of sugar in the blood), that sugar, called glucose, builds up in the blood. Insulin resistance can eventually lead to type 2 diabetes.

Continued high blood glucose can injure nerves throughout the body (called diabetic neuropathy). This can negatively affect breathing, promoting sleep-disordered breathing like sleep apnea.

“Studies have shown that OSA may be directly linked to insulin resistance,” Dr. Varghese says. According to research published in the Journal of Diabetes Investigation, “Snoring is associated with the development of diabetes, and excessive daytime sleepiness appears to modify insulin resistance.”

The common link between diabetes, insulin resistance, diabetic neuropathy and obstructive sleep apnea? Obesity.

Obese adults are much more likely than those with normal weight to develop multiple health issues.

“Patients often have obesity and type 2 diabetes. Both glycemic control and excess weight worsen with obstructive sleep apnea, and the severity of sleep apnea also worsens glycemic control while these patients are asleep and awake,” says Dr. Varghese.

Treatments that tackle both the symptoms and the causes

Maintaining a healthy weight, as well as drug-free and non-surgical approaches to managing sleep apnea, are the first line of defense to preventing type 2 diabetes and its complications.

Adults with OSA can wear a medical device over their nose and mouth during sleep that delivers continuous positive airway pressure (CPAP). This helps OSA patients breathe and sleep better, annd studies have shown that regular use can significantly lower their blood pressure and blood glucose levels.

“After three months use of just the CPAP alone, patients with metabolic syndrome have shown a reduction of HbA1c (which measures their blood glucose control) by an average of 0.2%, which is statistically significant,” Dr. Varghese says.

“However, weight loss and the management of type 2 diabetes are key to reducing insulin resistance, thus tackling OSA,” he says. “Studies show that if weight loss is also addressed, it can lead to a substantial difference in OSA measures (like the Apnea-Hypopnea Index). All the tools available — including nutrition, exercise and medications like glucagon-like peptide-1 (GLP-1) agonists — can be used to tackle weight.”

GLP-1 drugs are prescribed to treat diabetes and obesity.

Dr. Varghese says all adults who are at risk for sleep apnea should see their primary care physician or a sleep medicine specialist.

“Evaluation for OSA and endocrine conditions that can cause or worsen OSA (including hypothyroidism, Cushing syndrome, and acromegaly) is key,” he says. “After discussion with a sleep physician, if you are diagnosed with OSA, consider getting treatment with a CPAP device. Controlling your weight is also very important to reduce the development of diabetes complications and also for glycemic control.”

To schedule an appointment with the University of Miami Health System’s sleep medicine team, call 305-243-9999 or request an appointment online.

As a comprehensive sleep center, UHealth offers a wide range of innovative non-surgical and minimally invasive surgical treatments, often in combination with recommendations and treatments from UHealth’s related medical specialties, including endocrinology, ENT (ear, nose and throat), and cardiology.

Dana Kantrowitz is a contributor for UHealth’s news service.

Tags: blood sugar, Diabetes care in Miami, Dr. Ron Varghese, family history of diabetes, sleep apnea, treat type 2 diabetes