In a cross-sectional study analyzing data from the Guangzhou Biobank Cohort Study, Neil Thomas, from the University of Birmingham (United Kingdom), and colleagues studied 19,567 subjects, ages 50 to 93 years, surveying for lifestyle habits including frequency of napping, and assessing type-2 diabetes markers including fasting blood glucose levels.  The team indentified type-2 diabetes in 13.5% of the subjects, noting the disease was more prevalent in people who reported napping daily (15.1%) and in those who napped four to six times per week (14.7%). In a sub-sample of 3,822 participants who were re-contacted for additional information about sleep habits, the team found a statistically significant trend of increasing risk of diabetes with longer nap duration. Compared with people who never took naps, the risk of diabetes was 41% higher for people who took naps that lasted longer than 30 minutes and 35% higher for people whose naps lasted 30 minutes or less.  The researchers also observed these associations between napping and diabetes to be observed despite the fact that the nappers had higher levels of physical activity.  They conclude that: “Napping is associated with elevated prevalence of diabetes and impaired fasting glucose in this older Chinese sample.”