Objective: To examine racial differences in sleep duration and its relationship with diabetes.
Research design and methods: We used data from a nationally representative sample of U.S. adults (n = 130,943) participating in the National Health Interview Survey from 2004 to 2011. Usual sleep duration was self-reported and categorized as <7 h (short), 7 h (optimal), and >7 h (long). Diabetes status was based on self-reported diagnosis from a health professional.
Results: Participants' mean age was 50.6 years, 49% were men, and 13% were black. Compared with whites, blacks were more likely to report short sleep (37 vs. 28%) and less likely to get 7 h of sleep (24 vs. 33%). Diabetes (9,643 cases [9%] in whites and 3,612 cases [15%] in blacks) had a U-shaped distribution with sleep in whites (10, 7, and 9%, for short, optimal, and long sleep, respectively) and blacks (16, 13, and 15%). Suboptimal sleep duration was more strongly associated with diabetes in whites than in blacks among short (prevalence ratio 1.49 [95% CI 1.40-1.58] vs. 1.21 [1.09-1.34]) and long (1.32 [1.25-1.40] vs. 1.11 [1.00-1.23]) sleepers on the relative scale. Adjustment for socioeconomic status (SES) attenuated the short sleep-diabetes association in blacks (1.15 [1.02-1.29]), and the racial/ethnic difference in the short sleep-diabetes association became nonsignificant after SES adjustments.
Conclusions: Suboptimal sleep duration was positively associated with diabetes in blacks and whites, although diabetes prevalence was higher at any level of sleep in blacks. Socioeconomic factors appear to partly explain the association for short sleep in blacks as well as disparity between racial groups.