A study published in Diabetologia found an association between increased sleep time and an increased risk of type 2 diabetes in middle-aged and older women. The study looked at data from 59,031 women, aged 55 to 83, who had participated in the Nurses’ Health Study and did not have diabetes in 2000. The Nurses’ Health Study tracked, among other things, diabetes occurrence, diet, physical activity, and body weight. Sleep duration over the course of a 24-hour period was self-reported twice, in 1986 and 2000. By 2012, 3,513 participants had developed diabetes. After adjusting for diabetes risk factors, including BMI, researchers found that:
Compared with no change in sleep duration, increasing sleep by two or more hours each day was associated with a 15% increased risk of type 2 diabetes. Increased sleep was also associated with more weight gain.
Compared with no change in sleep duration, decreasing sleep was associated with poor diet and less physical activity.
This research adds to the growing body of evidence linking sleep habits with various health effects. However, because this study was based on limited data from questionnaires, more research is needed to determine whether there is an optimal amount of sleep for avoiding diabetes. In the meantime, it’s clear that getting enough shut-eye is important, but it’s also clear that getting too much may have negative health effects.