Obstructive sleep apnea has been linked to nerve damage in people with type 2 diabetes, according to a new study.
Researchers found the nerve damage, known as diabetic peripheral neuropathy, is linked to the severity of sleep apnea and the resulting blood oxygen desaturation which occurs while patients sleep.
People with obstructive sleep apnea stop breathing hundreds of times per night because the soft tissue of the upper airway collapses and blocks airflow. Most of these breathing stoppages end with a brief 'micro arousal', where the sufferer wakes very briefly, often with a choking or gasping for breath. Because these awakenings are so brief, the sufferer has no conscious memory of waking. OSA sufferers with diabetic peripheral neuropathy may experience numbness or tingling in their extremities, or damage to their major organs.
The study of 234 adults with type 2 diabetes found that sleep apnea was independently associated with diabetic peripheral neuropathy even after the researchers accounted for a number of other possible factors, including obesity, ethnicity, gender, age at diabetes diagnosis, and the length of time a person had diabetes.
The findings were published online ahead of print in the American Journal of Respiratory and Critical Care Medicine.
"Obstructive sleep apnea is known to be associated with inflammation and oxidative stress, so we hypothesized that it would be associated with peripheral neuropathy in patients with type 2 diabetes," lead author Dr. Abd Tahrani, a clinical lecturer in endocrinology and diabetes at the University of Birmingham in England, said in a news release from the American Thoracic Society.
However, while the study uncovered an association between obstructive sleep apnea and peripheral neuropathy in diabetic patients, it did not prove a cause-and-effect relationship.
Further research is needed to determine the role of sleep apnea and low blood oxygen levels in the development and progression of nerve damage in patients with type 2 diabetes, and to assess the potential impact of continuous positive airway pressure treatment on diabetic peripheral neuropathy, the study authors said.
Continuous positive airway pressure treatment, or CPAP, keeps obstructive sleep apnea patients' airways open while they sleep.