Sleep Apnea Linked to Development of Diabetes: Study

A study conducted on Canadian patients highlights the association between sleep apnea and diabetes.

Led by researchers at the University of Toronto, the new study evaluated 8,678 Canadian patients and found that obstructive sleep apnea (OSA) leads to the development of diabetes,  confirming earlier studies that highlighted the same. The patients in this study had  OSA without any signs or symptoms of diabetes.

"Our study, with a larger sample size and a median follow-up of 67 months was able to address some of the limitations of earlier studies on the connection between OSA and diabetes," said lead author Tetyana Kendzerska, MD, PhD, of the University of Toronto. "We found that among patients with OSA, the initial severity of the disease predicted the subsequent risk for incident diabetes."

A diagnostic sleep study between 1994 and 2010 was done and the subjects were followed through May 2011. The presence of diabetes was examined using the provincial -health administrative data.  With the help of the apnea-hypopnea index (AHI) the researchers assessed the severity of sleep apnea.  AHI is based on the number of apneas i.e. complete cessation of airflow and hyponeas i.e. partial cessation of airflow per hour of sleep.

The patients were further classified into the following: those having OSA (AHI<5), having mild (AHI 5-14.9), moderate (AHI 15-30) or severe (AHI>30) OSA.

It was seen that during the follow-up period, nearly 1,017 patients developed diabetes. After adjusting for certain risk factors, patients having AHI> 30 were 30 percent more likely to develop diabetes when compared to those with AHI<5. Those with moderate or mild OSA suffered a 23 percent increased risk of diabetes.

"After adjusting for other potential causes, we were able to demonstrate a significant association between OSA severity and the risk of developing diabetes," said Dr. Kendzerska. "Our findings that prolonged oxygen desaturation, shorter sleep time and higher heart rate were associated with diabetes are consistent with the pathophysiological mechanisms thought to underlie the relationship between OSA and diabetes."

The finding was documented in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.