The study involved 19,567 people in China between the ages of 50 and 93 years. About 71 percent of participants were women.
They received a physical exam. They also answered questions about their lifestyle and medical history. This included questions about their napping habits and daytime sleepiness.
Results show that 13.5 percent of the sample had type 2 diabetes. The rate of diabetes was 36 percent higher in people who reported napping four to six times per week. It was 28 percent higher in people who napped daily.
The results were unchanged when people with potential ill health and daytime sleepiness were removed from the analysis. This suggests that it is less likely that diabetes leads to daytime sleepiness. Instead the results raise the possibility that napping may increase the risk of diabetes.
But more research is needed to determine if napping plays a causative role in the development of diabetes. Many other factors may be involved in older adults.
“In many non-Mediterranean, Western countries a large proportion of those that nap are generally older or have other conditions that cause tiredness and create an urge to nap,” lead author Neil Thomas told the AASM. “The napping can therefore be a marker of disease.”
According to the authors, napping is a social norm in China. It is practiced at all ages starting in childhood. At least one nap per week was reported by 67 percent of participants. About 59 percent of these people reported napping daily.
The authors also noted that napping and diabetes were associated even though physical activity levels were higher in nappers. Physical activity has been shown to reduce the risk of diabetes.
Read more about naps and sleep and type 2 diabetes.
Image by Nomad Tales