Metabolic syndrome and its components as predictors of nonalcoholic fatty liver disease in a northern urban Han Chinese population: A prospective cohort study

Objectives: To explore the longitudinal effect of metabolic syndrome (MetS) and its components on the development of non-alcoholic fatty liver disease (NAFLD) and to evaluate the significance of MetS and its components as early markers of NAFLD risk in a northern urban Han Chinese population. Materials and methods: A total of 15,791 cohort members without NAFLD at baseline were included in the current study between 2005 and 2011. The baseline characteristics of the cohort were compared by MetS status at baseline and NAFLD status after follow-up. Cox proportional hazards models were used to estimate the unadjusted or adjusted hazard ratios (HRs) for development of NAFLD among individuals with MetS compared with individuals without MetS at baseline. Results: During 51,652 person-years of follow-up, 3913 (24.78%) new cases of NAFLD occurred between 2005 and 2011. In the unadjusted model, the HR (95% confidence interval [CI]) for NAFLD was 2.51 (2.30, 2.73). After adjusting for gender, age, diet, smoking status, and regular exercise, the HR was 1.94 (1.78, 2.13). Gender differences were observed, with adjusted HRs (95% CIs) of 1.89 (1.71, 2.09) and 1.72 (1.43, 2.07) among males and females, respectively. Compared with individuals without MetS components, the HRs were 1.92 (1.76, 2.09), 2.64 (2.40, 2.90) and 3.51 (3.15, 3.91) for individuals with one, two, or three or more MetS components, respectively. Moreover, participants with obesity or hyperlipidemia had a higher risk of NAFLD than patients with hypertension or hyperglycemia, with HRs of 2.03 (1.83, 2.25) for obesity, 1.94 (1.72, 2.19) for hyperlipidemia, and 3.01 (2.68, 3.37) for these factors in combination. Conclusion: The present study indicates that MetS and its components independently predict the risk of NAFLD in a northern urban Han Chinese population and suggests that people with MetS or its component should initiate lifestyle changes to prevent the development of NAFLD.