Sept. 18, 2015 -- Being sleepy and taking long naps during the day are both tied to worse odds of getting type 2 diabetes, a new review suggests.
Researchers from the University of Tokyo analyzed 10 studies from countries around the world, which included data on 261,365 participants. They found that "excessive daytime sleepiness" was linked to a 56% higher risk of getting type 2. And taking a long daytime nap (1 hour or more) was tied to a 46% higher risk. Shorter naps of less than an hour didn't raise a red flag, though.
The researchers didn't say what counts as excessive daytime sleepiness. Also, participants in the studies reported on their drowsiness and napping habits.
The new review was presented at the annual meeting of the European Association for the Study of Diabetes.
The researchers say in a press release that daytime napping might be a consequence of a night-time sleep disturbance, such as obstructive sleep apnea.
These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.