Sleep Apnea Severity Independently Predicts Glycemic Health

Sleep apnea has been linked with elevated blood sugar levels, suggesting people with the condition could be at an increased risk of cardiovascular illness and mortality.

Obstructive sleep apnea (OSA) is independently related to prevalent and incident systemic hypertension and there is growing evidence of an association with incident coronary artery disease, stroke and overall cardiovascular morbidity and mortality and an increased risk of metabolic dysfunction.

Scientists at St Vincent’s University Hospital (Dublin, Ireland) and an international team of collaborators analyzed 5,294 nondiabetic participants from the multinational European Sleep Apnea Cohort. The team measured levels of glycosylated hemoglobin (HbA1c), which correlates with average plasma glucose concentration. This measurement allows researchers to gain an understanding of blood sugar levels over a period of time. People with diabetes have higher levels of HbA1c and the risk of developing cardiovascular complications is increased as these levels are raised. The target levels for HbA1c are 4.0% to 5.9% for nondiabetics and up to 6.5% for diabetics.

The results found that levels of glucose concentration were significantly linked with the severity of sleep apnea. The participants were divided into groups based on their level of sleep apnea severity and HbA1c levels which rose from 5.24% in the group with lowest severity to 5.5% in the group with the highest severity. The findings highlight the need for clinicians to be aware of the risks of diabetes when treating sleep apnea. A somewhat stronger relationship was seen between OSA severity indices and HbA1c levels in non-obese than those in obese subjects, but a significant relationship was observed in both groups.

Walter T. McNicholas, MD, a professor of Respiratory Medicine and an author of the study said, “This is the largest study of its kind showing a link between sleep apnea severity and glucose levels. Clinicians need to focus on diabetes as an important coexisting illness when treating people with sleep apnea. Further studies are needed to understand the mechanisms behind these two conditions. I would also emphasize to patients the importance of weight control as a way to reduce the risks associated with the condition.” The study was published on April 2, 2014, in the European Respiratory Journal.

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