If you get less than six hours of sleep per night, your risk of developing impaired fasting glucose rises by a factor of 4.56, according to a report from the American Heart Association. 

Impaired fasting glucose, a common precursor to type 2 diabetes, occurs when the body does not efficiently use insulin. The result is the higher blood glucose readings that are typically found in people who are have pre-diabetic.

The study, conducted by the University of Buffalo, tracked 91 people who had been participants in a 1996 to 2003 investigation of 1,455 participants called the Western New York Health Study. The 91 had started the study in 1996 with fasting blood glucose levels of less than 100 mg/dl. By 2003, however, their BG levels had risen to between 100 mg/dl and 125 mg/dl-indicators of a pre-diabetes condition.

Researchers marched the 91 participants against a control group of 273 people, derived from the same previous study, who had started and finished the seven years at below 100 mg/dl.

Scientists asked participants, who were matched by sex and race, to self-report their nightly sleep duration. Participants were sorted by how many hours they slept during each night of a typical work week. A group of 25 who reported sleeping six or fewer hours nightly were called "short-sleepers"; a group of 24 who reported sleeping eight or more hours nightly were called "long-sleepers"; and 314 who reported sleeping between six and eight hours nightly were labeled "mid-sleepers." 

At the end of the six-year study, the researchers adjusted for age, body mass index, heart rate, high blood pressure, glucose and insulin concentrations, and family histories of diabetes and depression before concluding that the short-sleepers had a significantly higher risk of developing impaired fasting glucose than the mid-sleepers. (The long-sleepers did not experience any impaired fasting glucose.)

Although the study established a direct correlation between how much sleep individuals get and their risk of developing a pre-diabetes symptom, it did not show why shortened sleep is a contributing factor. Nobody knows if there is a genetic predisposition to shorter sleep spans, and research into that possibility seems to be a likely next step.