Sleep Duration and Obesity among Adults Under 65 Years of Age and the Elderly in Taiwan

SummaryBackgroundThis study investigated the determinants of obesity in adults younger than 65 years of age and those older than 65 years, focusing on the relationship between sleep duration and obesity after controlling other factors.MethodsThe data were obtained from the National Survey on Knowledge, Attitude, and Practice of Health Promotion 2002 in Taiwan. A total of 23,809 participants completed this survey, including 3731 elderly persons (65 years of age and older) and 20,078 adults (between 18 and 64 years of age). A multiple logistic regression model was adopted, and obesity was defined as a binary dependent variable by the criteria of body mass index (BMI) ≥27 kg/m2.ResultsA U-shaped correlation between obesity and sleep duration was identified in this study. Adults <65 years who slept for 7 hours/night (males/females: OR = 0.74/0.92) and elderly people who slept for 6 hours/night (males/females: OR = 0.84/0.77) showed a lower risk of obesity than the control group (5 hours/night).ConclusionSelf-reported habitual sleep duration had a U-shaped relationship with obesity in the two populations. The conflict of interest was that the cut-off point of sleep duration differed by 1 h (< 65-year-old adults: 7 h; elderly: 6 h). To preclude the possible bias introduced by self-reporting, using multiple measurements of sleep parameters is recommended in future research.