Sleep Duration and Risk of Obesity: Analysis of the National Health Interview Survey

Introduction: This study assessed whether the short sleep-obesity link differentially affects black and white Americans.

Method: Analysis was based on data obtained from 29,818 Americans (age range: 18-85 years) who participated in the 2005 National Health Interview Survey, a cross-sectional household interview survey, using 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 (e.g., hypertension, heart disease, diabetes, and arthritis). Subjective and anthropometric data including mood, habitual sleep duration and height/weight were also collected.

Results: Compared with whites, blacks were less likely to report sleeping 7 hours [23% vs. 30%, p<0.0001], with characteristically greater prevalence of short sleep (≤5 hrs) [12% vs. 8%, p<0.0001]. Blacks had a greater prevalence of obesity (BMI ≥30kg/m²) than did whites [52% vs. 38%, p<0.0001]. Short sleep was associated with obesity among both blacks and whites [OR=2.22, 95% CI: 1.68-2.95, p<0.0001; and OR= 1.82, 95% CI: 1.60-2.07, p<0.0001, respectively]. Multivariate-adjusted ORs for blacks and whites were 1.78 [95% CI: 1.30-2.45, p<0.0001] and 1.43 [95% CI: 1.24-1.66, p<0.0001], respectively. Demographic and medical risk factors were adjusted.

Discussion: Race significantly influences the risk of obesity associated with short sleep duration. An excess of 35% of blacks showed greater obesity risk associated with short sleep. Further research is needed to examine the mediators of excess risk among Black population.