The effect of race/ethnicity on the risk of diabetes associated with sleep duration has not been systematically investigated. This study assessed whether blacks reporting short (<6 hours) or long (>8 hours) sleep durations were at greater risk for diabetes than their white counterparts. In addition, this study also examined whether the influence of race/ethnicity on associations between abnormal sleep durations and the presence of diabetes were independent of individuals' sociodemographic and medical characteristics.

A total of 29,818 Americans (age range: 18-85 years) enrolled in the 2005 National Health Interview Survey, a cross-sectional household interview survey, provided complete data for this analysis.

Of the sample, 85% self-ascribed their ethnicity as white and 15% as black. The average age was 47.4 years, and 56% were female. Results of univariate regression analysis adjusting for medical comorbidities showed that black and white participants who reported short sleep duration (<6 hours) were more likely to have diabetes than individuals who reported sleeping 6 to 8 hours (odds ratios 1.66 and 1.87, respectively). Likewise, black and white participants reporting long sleep duration (>8 hours) had a greater likelihood of reporting diabetes compared with those sleeping 6 to 8 hours (odds ratios 1.68 and 2.33, respectively). Significant interactions of short and long sleep with black and white race were observed. Compared with white participants, greater diabetes risk was associated with being short or long sleepers of black race.

The present findings suggest that American short and long sleepers of black race may be at greater risk for diabetes independently of their sociodemographic profile or the presence of comorbid medical conditions, which have been shown to influence habitual sleep durations. Among black individuals at risk for diabetes, healthcare providers should stress the need for adequate sleep.