A study has shown that people who sleep less than six hours per night have an increased risk of developing impaired fasting glucose, or pre-diabetes.

The research presented this week at the American Heart Association's Annual Conference on Cardiovascular Disease Epidemiology and Prevention showed people averaging less than six hours of sleep a night to have nearly five times the chance of developing the disease compared to those who averaged six to eight hours of sleep.

A normal fasting blood glucose level is less than 100 mg/dL while a fasting blood glucose result of 100mg/dL to 125 mg/dL is considered impaired fasting glucose. An impaired fasting glucose is commonly referred to as pre-diabetes because many people with pre-diabetes go on to develop type 2 diabetes.

Study lead author Lisa Rafalson, a research assistant professor at the University at Buffalo in New York, in a news release issued by the association said, "This study supports growing evidence of the association of inadequate sleep with adverse health issues. Sleep should be assessed in the clinical setting as part of well-care visits throughout the life cycle."

Researchers examined sleep habits of 1,455 people in the Western New York Health Study and identified 91 participants who had fasting blood glucose levels of less than 100 milligrams per deciliter (mg/dL) during baseline exams between 1996 and 2001.

They compared fasting glucose levels over a six year period and found at follow-up exams in 2003-2004, the participants had higher blood fasting glucose levels -- between 100 mg/dL and 125 mg/dL. These 91 participants were compared with 273 people who had blood glucose levels of less than 100 mg/dL both at baseline and follow-up.

The researchers matched groups according to gender, race/ethnicity, and year of study enrollment. The participants reported how much sleep they averaged during the week and were divided into three categories. The first were the short sleepers who slept less than six hours, mid-sleepers of six to eight hours sleep, and long sleepers of more than eight hours.

The researchers noted that in the six year study period participants who slept on average less than six hours a night during the work week were 4.56 times more likely than those getting six to eight hours of sleep to convert from normal blood sugar levels to impaired fasting glucose. Factors such as age, obesity, and family history of diabetes were taken into account.

In the case of people who slept more than eight hours compared to those who slept six to eight hours no significant difference in fasting glucose levels or risk of developing type 2 diabetes was found.

"This study supports growing evidence of the association of inadequate sleep with adverse health issues," said Rafalson. "Our findings will hopefully spur additional research into this very complex area of sleep and illness."