Obstructive sleep apnoea is associated with nerve damage in people with type 2 diabetes, according to a new study.
The severity of this type of nerve damage - called diabetic peripheral neuropathy -- is linked with the extent of sleep apnoea and the degree of low blood oxygen levels that occur while patients sleep, the researchers found.
People with obstructive sleep apnoea subconsciously awaken many times a night - even dozens of times an hour - because their airways close, disrupting their breathing. Those with diabetic peripheral neuropathy may have numbness or tingling in their extremities, or damage to their major organs.
How the study was done
The study of 234 adults with type 2 diabetes found that sleep apnoea 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 in the American Journal of Respiratory and Critical Care Medicine.
"Obstructive sleep apnoea is known to be associated with inflammation and oxidative stress, so we hypothesised 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.
However, while the study uncovered an association between obstructive sleep apnoea 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 apnoea 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 apnoea patients' airways open while they sleep.
All about diabetes
The U.S. National Institute of Neurological Disorders and Stroke has more about diabetic neuropathy.
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