Study objectives: To assess the association between nightly total sleep time (TST) and obesity in an epidemiologic sample of metropolitan Detroit, Michigan.
Methods: Data were collected through telephone interviews completed using a population-based sample of 3158. The self-reported average nightly TST during the 2 weeks before the interview was used to divide the sample into 6 groups (hours per night of sleep; < or = 5, > 5 < or = 6, > 6 < or = 7, > 7 < or = 8, > 8 < or = 9, > 9). Obesity was defined as a body mass index > or = 30. Health and demographic variables were also assessed.
Results: The overall prevalence of obesity was 24.8% and was significantly higher in individuals with lower amounts of TST. Compared with those with 7 to 8 hours of TST, individuals obtaining 5 hours or less and more than 5 but 6 hours or less of TST had significantly increased odds of being obese, after controlling for age, sex, loud snoring, hypertension, diabetes, arthritis, and alcohol intake (odds ratio = 1.7, 95% confidence interval = 1.3-2.3 and odds ratio = 1.4, 95% confidence interval = 1.1-1.8, respectively). A low TST was a significant predictor of a high body mass index. Furthermore, a low TST was also a significant predictor of diabetes, prior to controlling for body mass index. Interestingly, the prevalence of reduced habitual TST (< or = 5 hours) was higher in African Americans, in comparison with Caucasians (18.7% vs 7.4%; p < .001).
Conclusions: Our population-based data suggest that short sleep duration is associated with elevated prevalence of obesity and adds to the growing body of evidence supporting this relationship.