The association between obesity and short sleep duration: a population-based study.

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.