People with obstructive sleep apnea may have an increased risk of developing diabetes, according to a recent study.

Researchers led by Tetyana Kendzerska of the University of Toronto demonstrated a link between obstructive sleep apnea and the development of diabetes. The findings confirm earlier evidence of such a relationship from smaller studies with shorter follow-up periods.

"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."

For the study, researchers recruited more than 8,500 Canadian patients with suspected obstructive sleep apnea without diabetes at baseline. The participants underwent a diagnostic sleep study between 1994 and 2010 and were followed through May 2011 using provincial health administrative data to examine the occurrence of diabetes.

The severity of the participants' sleep apnea was assessed with the apnea-hypopnea index, which indicates severity based on the number of apneas (complete cessation of airflow) and hypopneas (partial cessation of airflow) per hour of sleep. Patients were classified as not having OSA (AHI < 5), or having mild (AHI 5-14.9), moderate (AHI 15-30) or severe (AHI>30) OSA.

During the follow-up, 11.7 percent of the patients developed diabetes. In analyses adjusting for known risk factors for diabetes, including age, sex, body mass index, neck circumference, smoking, income status and comorbidities at baseline, patients with severe obstructive sleep apnea had a 30 percent higher risk of developing diabetes than those who do not suffer from the disorder.

"After adjusting for other potential causes, we were able to demonstrate a significant association between [obstructive sleep apnea] severity and the risk of developing diabetes," Dr. Kendzerska said. "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 [obstructive sleep apnea] and diabetes."

The study was recently published in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.