Association between sleep duration and weight gain and incident overweight/obesity: longitudinal analyses from the China Health and Nutrition Survey

Objective To evaluate the association between sleep duration and weight gain and incident overweight/obesity in the population of China. Methods Data were derived from the China Health and Nutrition Survey. Adult participants with baseline data of sleep duration and body mass index (BMI) and who received at least one follow-up evaluation were selected to analyze the association of sleep duration with weight gain (n= 12,871) and incident overweight/obesity (n= 7,752). Daily sleep duration was categorized into five groups: <= 6, 7, 8 (as reference), 9, and >= 10 h. The study outcomes were weight gain >= 5 kg and incident overweight/obesity (BMI >= 24 kg/m(2)). Results Adjusted Cox proportional hazards models showed that only short sleep duration (<= 6 h) significantly increased the risk of weight gain >= 5 kg (HR: 1.160, 95% CI: 1.005-1.339,p < 0.001) and incident overweight/obesity (HR: 1.403, 95% CI: 1.185-1.660,p < 0.001), whereas sleep duration 9 h was significantly associated with a lower risk of incident overweight/obesity (HR: 0.817, 95% CI: 0.700-0.953,p = 0.010). No significant correlation was found between long sleep duration (> 10 h) and the risk of weight gain >= 5 kg and incident overweight/obesity. Conclusion Short sleep duration is a risk factor for the development of weight gain >= 5 kg and incident overweight/obesity in Chinese adults, whereas long sleep duration had no effect on future obesity.