Obstructive sleep apnea is linked with an increased risk of developing type 2 diabetes, new research shows.

The findings support recommendations from the International Diabetes Federation that patients with one condition be screened for the other, too, the research teams notes in the journal Sleep Medicine.

Sleep apnea occurs when a person's airway becomes partially or completely blocked during sleep, and as a result, breathing intermittently stops and starts. About 13 percent of men and 6 percent of women have moderate to severe undiagnozed sleep apnea, the researchers say.

"Over the last two decades, evidence has been accruing that sleep apnea may be associated with insulin resistance, glucose intolerance, and type 2 diabetes," study leader Mako Nagayoshi of Nagasaki University Graduate School of Biomedical Science in Japan told Reuters Health by email.

Past studies tying sleep apnea to diabetes were limited by a small number of participants and other factors, Nagayoshi and colleagues say.

For the new study, they used data from 1,453 participants with an average age of 63. All participants underwent in-home sleep studies and did not have diabetes when the research began.

Based on the sleep studies, the researchers categorized the participants as being normal sleepers or having mild, moderate or severe sleep apnea.

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After roughly 13 years, 285 people developed type 2 diabetes. Those with severe obstructive sleep apnea at the start of the study were about 70 percent more likely to develop diabetes than those classified as normal. The increased risk remained even when the researchers only included people who were obese.

About one in 10 adults have diabetes, according to the World Health Organization. Most have type 2 diabetes, which occurs when the body can't make or process enough of the hormone insulin.

Obesity increases the risk of both sleep apnea and diabetes, said Paul E. Peppard, a sleep disorder researcher at the University of Wisconsin School of Medicine and Public Health in Madison.

The new study and past research suggest there is a direct link between obstructive sleep apnea and diabetes, but ironclad evidence that it's behind a significant portion of diabetes cases does not yet exist, said Peppard, who was not part of the new study

"These findings underscore the need to prevent sleep apnea and screen for sleep apnea in patients particularly at risk for developing diabetes - e.g., overweight and physically inactive people," he told Reuters Health by email. "Behaviors such as healthy weight maintenance and reducing time in sedentary activities would simultaneously reduce the risk (of) developing sleep apnea and diabetes."

People with diabetes should also be screened for sleep apnea, and people with sleep apnea should be screened for diabetes, said Dr. Rashmi Nisha Aurora, a sleep medicine expert at Johns Hopkins University School of Medicine in Baltimore.

"Healthcare providers need to be aware of the association and educate their patients and the community," Aurora told Reuters Health by email.

Ongoing research is still investigating whether treating sleep apnea reduces diabetes risk, said Aurora, who was also not involved in the study.