Metabolic syndrome is an important risk factor for cardiovascular disease, type 2 diabetes mellitus, and all-cause mortality. However, the relationship between napping and metabolic syndrome remains contradictory. The aim of this study was to evaluate the association between nap duration after lunch and prevalence of metabolic syndrome, and subgroup differences in the associations among a government employee population. A total of 5129 participants (mean age 39.4 years) were included in this study. Nap duration after lunch was self-reported, and metabolic syndrome was defined according to the Joint Interim Statement in 2009. Multivariate logistic regression models and adjusted restricted cubic spline functions were used to examine the association and dose-response relationship between nap duration after lunch and prevalence of metabolic syndrome. Of the participants, 17.3% had metabolic syndrome and 81.4% were habitual nappers. Adjusted odds ratio (OR) (95% confidence interval (CI)) of metabolic syndrome for longer nap duration (>90 min) per day was 1.77 (95% CI 1.09 to 2.89), compared with reference (~30 min). Results of stratification analyses indicated the association was found only among females (OR 3.02, 95% CI 1.38 to 6.57), participants without mood symptoms (OR 1.97, 95% CI 1.19 to 3.25), and those having longer night sleep duration (≥8 h) (OR 2.34, 95% CI 1.20 to 4.56). Longer nap duration was also associated with components of metabolic syndrome, including elevated waist circumference, elevated fasting plasma glucose, and elevated triglycerides. In conclusion, longer nap duration after lunch was associated with a higher prevalence of metabolic syndrome in females, people without mood symptoms, and people having longer night sleep duration.

Background: Evidence indicates that certain healthy lifestyle factors are associated with non-alcoholic fatty liver disease (NAFLD). However, little is known about the effect of combined healthy lifestyle factors. Objective: To assess the association of combined healthy lifestyle factors with the incidence of NAFLD. Methods: This cohort study was conducted in Changsha, Hunan Province, China. The healthy lifestyles factors studied were not being a current smoker, having a healthy diet, engaging in physical activity, having a normal body mass index (BMI) and engaging in non-sedentary behavior. NAFLD was diagnosed based on abdominal ultrasonography. Logistic regression models were conducted to investigate the associations being studied. Results: Of the 5411 participants, 1280 participants had NAFLD, with a prevalence of 23.7% at baseline. The incidence of NAFLD among participants without NAFLD at baseline was found to be 7.2% over a mean follow-up of 1.1 years. Compared with participants with 0–1 low-risk factors, the OR of NAFLD was 0.50 (95% CI: 0.29–0.82, p = 0.008) for those with at least 4 low-risk factors. Similar associations were observed in subgroup analyses and sensitivity analyses. Conclusion: This study suggests that a combined healthy lifestyle pattern may considerably decrease the risk of NAFLD in Chinese government employees.