Less or too much sleep raises diabetes risk

Not getting enough sleep each night, or getting too much sleep, may increase a person's risk of developing non-insulin dependent (type 2) diabetes, independent of other factors. Researchers from the Yale University in New Haven, Connecticut found that sleep duration may be a novel risk factor for the development of clinical diabetes. They studied the long-term (15-year) impact of sleep duration on the development of diabetes in more than 1,100 middle-aged and elderly men who were free of diabetes in 1987-1989 and were followed until 2004. Men getting no more than 6 hours of sleep per night, as well as those getting more than 8 hours of sleep per night, were at significantly increased risk for developing diabetes, compared to men getting 7 to 8 hours of sleep each night. The risk of diabetes was roughly twofold higher in men reporting short sleep duration and more than threefold higher in those reporting long sleep duration, compared with men sleeping 7 to 8 hours nightly. This U-shaped distribution of risk with respect to sleep duration has been reported previously for coronary heart disease, mortality due to any cause, and diabetes in women. The elevated risks with short or long durations of sleep remained essentially unchanged after adjustment for several factors including age, blood pressure, smoking status and waist circumference. However, relative risks were reduced considerably when adjusted for testosterone, suggesting to the team that the effects of sleep on diabetes could be mediated via changes in the body's levels of this hormone.