Sleep duration and risk of diabetes among black and white Americans

Introduction: The study examined whether sleep duration has an independent association with diabetes among black and white participants.

Method: Participants (n=29,818) in the 2005 National Health Interview Survey (NHIS) provided data for the present analysis. The age range of the sample was: 18-85 years; 85% were white and 15%, black; 56% were women. The NHIS is a cross-sectional household interview survey, which uses a multistage area probability design. Probability samples of the civilian population of all 50 states and DC were obtained. During face-to-face interviews conducted by trained interviewers from the U.S. Census Bureau, respondents provided socio-demographic data and information about physician-diagnosed chronic conditions. They estimated their habitual sleep duration and provided height and weight data.

Results: Prevalence of obesity (BMI≥30kg/m2) for blacks and whites was 52% and 38%, respectively [p<0.0001]. Prevalence of diabetes for blacks and whites was 12% and 8%, respectively [p<0.0001]. Odds ratios for diabetes associated with short sleep (≤5hrs) and long sleep (≥9hrs) were 1.93 [95% CI: 1.59-2.33, p<0.0001] and 2.21 [95% CI: 1.83-2.63, p<0.0001], respectively. Adjusting for effects of age, sex, ethnicity, obesity, reduced OR to 1.24 [95% CI: 1.01-1.54, p<0.05] and to 1.48 [95% CI: 1.21-1.81, p<0.01] among short sleepers and long sleepers respectively.

Discussion: Both short and long sleepers are at great risk for diabetes, independently of their age, sex, ethnicity, or the presence of obesity. Individuals sleeping longer than 8 hours may be particularly vulnerable. Further research is needed to identify the mechanisms by which long sleep duration increases diabetes risk.