Association between metabolic syndrome and the development of non-alcoholic fatty liver disease

The aim of this study was to examine the effects of metabolic syndrome (MS) and the number of MS components on the development of non-alcoholic fatty liver disease (NAFLD). A total of 1,343 males and 574 females aged ≥50 years without NAFLD at baseline were included. Information on lifestyle, including alcohol use and personal history, was collected by face-to-face interviews. Biochemical parameters were assayed using fasting blood samples. NAFLD was diagnosed by abdominal ultrasonography. During follow-up at an average of 4.8 years, 223 patients developed NAFLD. Following adjustment for multiple covariates, age was an independent protective predictor [hazard ratio (HR), 0.96; 95% confidence interval (CI), 0.95–0.98], while the independent risk predictors were obesity (HR, 2.81; 95% CI, 2.14–3.69), higher triglycerides (HR, 2.56; 95% CI, 1.95–3.32) and alanine aminotransferase (HR, 1.004; 95% CI, 1.000–1.008). Participants with a diagnosis of MS had a significantly increased risk of developing NAFLD (HR, 3.17; 95% CI, 2.42–4.14). A greater number of MS components was significantly associated with a higher risk of NAFLD (all adjusted P for trend <0.001). Compared with those without any components of MS, participants with only one component of MS had a 3.6-fold higher risk of developing NAFLD (adjusted HR, 3.64; 95% CI, 1.50–8.88). The diagnosis and the number of components of MS were prospectively associated with the risk of developing NAFLD. Even in those with only one component of MS, the risk increased by 2.6-fold compared with that for the individuals without any components, suggesting a beneficial effect of intervention at the very early stage of MS on the prevention of NAFLD.