Subjects

The characteristics of subjects enrolled in this study has been described before (Wang et al., 2015). Briefly, our study included 384 ultrasound (US) diagnosed NAFLD patients and 384 age- and gender-matched healthy controls from the same geographic areas as the patients. All the subjects were recruited from individuals conducting health examination in the Shanghai Jiao Tong University Affiliated First People’s Hospital (Shanghai, China). The mean age of both case and control groups was 45±13 years old, and both of them were consisted of 229 males and 155 females. Subjects with a history of heavy alcohol consumption (>20 g/day) and other specific diseases that could contribute to fatty liver, such as hepatitis B and C virus infection, drug-induced liver disease, were excluded from the study. US-based NAFLD diagnoses were made by one experienced operator without knowing clinical and biochemical evaluations of the participants. The guidelines used for diagnosis were adopted from the Chinese National Consensus Workshop on NAFLD (Zeng et al., 2008). Patients with moderate to severe fatty liver diseases were selected in order to increase the diagnostic accuracy and reliability (Hernaez et al., 2011). All subjects were unrelated and self-reported Han Chinese living in the Shanghai metropolitan area. The study conforms to the principles of the Declaration of Helsinki. All the participants have given their written informed consent, and the study method was approved by the ethical committee of the Shanghai Jiao Tong University.