Day Napping and Short Night Sleeping Are Associated With Higher Risk of Diabetes in Older Adults

OBJECTIVE: To examine whether day napping or short night sleeping is associated with higher risk of diabetes. RESEARCH DESIGN AND METHODS: This was a prospective study of hours of day napping and night sleeping assessed in 1996-1997 in relation to diabetes diagnosed between 2000 and 2006 (n = 10,143) among 174,542 participants in the National Institutes of Health (NIH)-AARP Diet and Health Study. Odds ratios (ORs) and 95% CI were derived from multivariate logistic regression models. RESULTS: Longer day napping was associated with a higher risk of diabetes. After adjustment for potential confounders, ORs were 1.23 (95% CI 1.18-1.29) for those reporting or =1 h of napping compared with individuals who did not nap (P(trend) or =9 h. In both analyses, additional adjustment for BMI only modestly attenuated the associations. Further analysis showed a statistically significant interaction between hours of napping and sleeping on diabetes (P(interaction) or =1 h of napping, both long and short sleeping was associated with higher risk. CONCLUSIONS: Day napping and short night sleeping are associated with higher risk of diabetes. The association between sleep duration and diabetes may be modified by napping habit.