Non-linear relationship between sleep duration and metabolic syndrome: A population-based study.

The aims of this study were to evaluate the prevalence of metabolic syndrome (MetS) and explore the association between sleep duration and MetS. This study enrolled 8 272 adults aged 18 years and older from 6 urban and 8 rural areas during 2013 to 2014in Henan China. Participants were interviewed about demographic characteristics, lifestyle factors and medical history, and physical measurements were performed. The relationships between sleep duration and MetS were evaluated and plotted by Restricted Cubic Spline Regression. The mean age was 51.5 years (SD 14.2) and 4 916 (59.4%) were female. The crude prevalence of MetS was 30.3% and the age-standardized rate was 23.6%. Men were more likely to have MetS than women (P = .01). MetS was positively associated with age, education, smoking, drinking, BMI and sleep duration, and seemed irrelevant to occupation and sedentary behavior. In terms of individual component of MetS, high blood pressure was the most prevalent component for both men and women, while the lowest prevalent was high triglycerides in men and for women was low high-density lipoprotein cholesterol (HDL-C). There was a U-shaped relationship between sleep duration and MetS and its components. Sleep duration 9 hours were associated with higher risk of MetS (OR from 1.10 to 2.15). The MetS was prevalent, and more than half of total adult population was suffering from high blood pressure. Sleep duration may be a determinant of metabolic health. Both short (<6 hours) and long sleep duration (>9 hours) was linked to an increased risk of MetS.