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Causes of Obstructive Sleep Apnea

Obstructive Sleep Apnea and Overweight continued...

In addition, extreme obesity (defined as a BMI above 40) is associated with obesity-hypoventilation syndrome (Pickwickian syndrome), which can occur alone or in combination with obstructive sleep apnea. In this syndrome, which affects up to 25% of the extremely obese, excess body fat not only interferes with chest movement but also compresses the lungs to cause shallow, inefficient breathing throughout the day and night.

Although modest weight loss improves obstructive sleep apnea, it can be difficult for fatigued and sleepy patients to lose weight. In extremely obese patients, bariatric surgery is associated with an 85% success rate in improving the symptoms of obstructive sleep apnea.

Demographics and Obstructive Sleep Apnea

In middle-aged adults, the prevalence of obstructive sleep apnea is estimated to be 4%-9%, although the condition is often undiagnosed and untreated. Among people over age 65, it's estimated that at least 10% have the condition. Aging affects the brain's ability to keep upper airway throat muscles stiff during sleep, increasing the likelihood that the airway will narrow or collapse.

Obstructive sleep apnea is up to four times as common in men as in women, but women are more likely to develop sleep apnea during pregnancy and after menopause. In older adults, the gender gap narrows after women reach menopause.

Postmenopausal women who receive hormone replacement therapy are significantly less likely than those who don't to develop obstructive sleep apnea, suggesting that progesterone and/or estrogen may be protective. But hormone replacement therapy is not considered to be an appropriate therapy for the condition, because it can affect health in other ways.

Other factors associated with obstructive sleep apnea include:

  • Family history. About 25%-40% of people with obstructive sleep apnea have family members with the condition, which may reflect an inherited tendency toward anatomical abnormalities.
  • Ethnicity. Sleep apnea also is more common in African-Americans, Hispanics, and Pacific Islanders than in whites.


Complications Related to Obstructive Sleep Apnea

Increasing evidence suggests that obstructive sleep apnea is strongly associated with conditions such as high blood pressure (hypertension), stroke, heart attack, diabetes, gastroesophageal reflux disease, nocturnal angina, heart failure, hypothyroidism, and an abnormal heart rhythm. About half of sleep-apnea patients have hypertension, and untreated obstructive sleep apnea increases the risk of heart-related illness and death.

In addition, obstructive sleep apnea is associated with excessive daytime sleepiness, which increases the risk for motor vehicle accidents and depression.

Some complications may be related to the release of stress hormones, which may be triggered by frequent decreases in blood oxygen levels and reduced sleep quality. Stress hormones can increase heart rate and also can lead to the development or worsening of heart failure.

Medical treatment -- which includes control of risk factors, use of continuous positive airway pressure (CPAP) or oral appliances, and surgery -- may improve signs and symptoms of obstructive sleep apnea and its complications.


WebMD Medical Reference

Reviewed by Varnada Karriem-Norwood, MD on June 24, 2013

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