British scientists say that they have discovered a link between obstructive sleep apnea (OSA) and diabetic peripheral neuropathy. OSA is defined as having five or more events per hour of hypopnea (abnormally slow or shallow breathing). The researchers, from the University of Birmingham, UK, report that the association between the two conditions is strong despite other factors that could be used to explain the correlation. According to their findings, published in the American Journal of Respiratory and Critical Care Medicine, the severity of the neuropathy correlates with the degree of OSA.
The researchers studied 234 patients, with men comprising 58 percent of the group. The ethnic mix was 55 percent European and 45 percent South Asian. Of the patients with type 2 diabetes, two-thirds had OSA, and 60 percent of that subgroup had peripheral neuropathy. In contrast, 27 percent of the patients who did not have OSA had peripheral neuropathy. The patients were tested in a one-night, at-home sleep study using a portable device.
The UK researchers decided to investigate a potential OSA/diabetic neuropathy link after noting two things: First, nobody really understands how neuropathy develops, which is one reason that no satisfactory treatment for it has emerged. Second, sleep apnea has known associations with health problems that attend diabetes. Investigating whether OSA is linked to neuropathy looked like a promising line of research.
The scientists said that although their study establishes a correlation between OSA and diabetic neuropathy, it does not establish causation.In their report, however, they noted that they had amassed enough data to support further research into the connection. They also suggested investigating whether the use of continuous positive airway pressure (CPAP) in OSA has any impact on complications from diabetes, including neuropathy. In CPAP therapy, patients don a mask that blows a stream of air into their nose to keep their air passages open.