Two new research reports, presented at the American Thoracic Society 2007 International Conference, indicate that obstructive sleep apnea ups your risk of type 2 diabetes and increases your risk of heart attack.

Apnea means "without breath" in Greek ("A" means "without," as in "asymptomatic," and "pnea" means breath, as in "pneumatic" and "pneumonia.") In obstructive sleep apnea (OSA), the upper airway is obstructed when it narrows or collapses during sleep, so breathing stops temporarily.

Consequently, the sleeper may be aroused up to hundreds of times each night, just enough to start breathing again. Usually the sleeper has no recollection of the partial waking episodes, but feels tired and poorly rested every day.

Often OSA accompanies obesity, perhaps because more tissue develops in the throat and at the back of the mouth. When that tissue collapses during the relaxation of sleep, less oxygen makes it into the lungs and bloodstream. This lack of oxygen may trigger the body's "fight or flight" response, producing high levels of cortisol that lead to insulin resistance and glucose intolerance.

The first study, from the Yale School of Medicine, examined 593 patients who had been referred for evaluation of apnea. Each patient underwent an overnight sleep study in a lab and then was followed for up to six years. The researchers found that patients diagnosed with OSA had over 2-1/2 times the risk of developing type 2 diabetes compared to those without it. The more severe their apnea, the higher was the risk of diabetes.

The second study evaluated a group of 1,123 patients who underwent the same type of overnight sleep evaluation and were then followed for four to five years. The study found that OSA increased a person's risk of having a heart attack or dying by thirty percent over that period. Again, the more severe the OSA, the greater was the risk.

It is recommended that people who have symptoms of OSA, including loud snoring and day-time sleepiness, consult their physician. The most effective non-surgical treatment for OSA is nasal continuous positive airway pressure (CPAP); it involves wearing a mask over the nose that forces air into the airway during sleep, thereby preventing the airway from closing. Previous research has indicated that use of CPAP may reduce A1c levels by an average of twelve percent.

Sources: American Thoracic Society International Conference

For more information on this subject, see "Sleep Apnea", September 2006.