1, obesity – fatty liver incidence is increasing year by year In the 1960s, alcoholic liver cirrhosis accounted for 42% in Europe, 66% in America, 11% in Asia, and less than 5% in China compared with liver cirrhosis due to other etiologies. However, in the past 30 years, with the improvement of living standards, changes in diet structure and increasing alcohol consumption, the incidence of alcoholic liver and fatty liver has increased rapidly, accounting for 15% to 20% of the causes of cirrhosis. The causes of fatty liver are various, but the most important of them are obesity, alcohol consumption and diabetes. The incidence of fatty liver in China’s general population is 10%, while the incidence of fatty liver in obese people is 50% to 75%. A survey of 4009 cadres in Shanghai found that 31,6% were obese, 40% to 50% were type II diabetics with fatty liver, 57,7% were alcoholics, and 24,5% were over 50 years old. In Beijing, the incidence of fatty liver in 14 units in 2004 was found to increase year by year from 23.2% in 1998 to 26.2% in 2003. Recently, the epidemiological survey results of fatty liver in Guangdong showed that the prevalence of fatty liver in urban population was 17.5%, while 31.9% of overweight people with body mass index of 23-28 suffered from fatty liver, and the incidence of fatty liver in obese people was 55.4%. Therefore, obesity is the main cause of alcoholic and non-alcoholic fatty liver disease. The obese population in China is increasing year by year (BMI>25 is the standard for obesity: Figure 1). 2009 Beijing survey found that BMI>28 is the standard for obesity: 36.4% of Beijingers are overweight and 13.5% are obese. Therefore, obesity-drinking-fatty liver has become the second leading cause of liver disease in China. In 1995, Japanese scholars reported that the prevalence of NAFLD in children aged 4 to 12 years was 2.6%, and 83% of obese children had ultrasound-confirmed fatty liver, of which 24% had increased ALT. American scholars have also obtained similar results. 2, chronic viral hepatitis combined with fatty liver is increasing year by year Hepatitis virus infection is the main cause of liver disease in China, the whole about 2 billion people have evidence of HBV infection. In the chronic HBV infection, about 15-25% will eventually die from liver failure, cirrhosis and primary hepatocellular carcinoma associated with HBV infection. 2006, the Ministry of Health conducted a national sero-epidemiological survey on hepatitis B in the population, showing that the national hepatitis B surface antigen carriage rate for people aged 1-59 years was 7.18% (2002 national hepatitis B sero-epidemiological survey results. HBsAg prevalence rate was 9.09%). Among them, the hepatitis B surface antigen carriage rate was 0.96% for those aged 1-4 years, 2.42% for those aged 5-14 years, and 8.57% for those aged 15-59 years. However, the incidence of hepatitis C in viral hepatitis is clearly on the rise, and in the 1992 seroepidemiological survey of viral hepatitis in China, the population anti-HCV positive rate was 3.2%. Clinical studies have shown that the incidence of cirrhosis after 7 to 50 years of HCV infection is 0,3% to 55,0%, and the incidence of liver cancer is 0-23%, and the incidence of cirrhosis is about 10% to 15% after an average of 20 years of infection. So, what is the role of obesity-fatty liver-metabolic syndrome in the progression of chronic viral hepatitis disease? It has been reported that about 50% of adult CHC patients have hepatocellular steatosis [7], and in children about 10% of CHC patients have NASH (non-alcoholic fatty liver disease). After excluding the common causes of hepatocellular steatosis (including obesity, diabetes, hyperlipidemia and alcoholism), hepatocellular steatosis is still present in 30% of CHC patients. Early literature reported that hepatocellular steatosis was present in about 27%-51% of CHB patients, and the detection rate of NAFLD in CHB varied widely among countries. Epidemiological data from China show that the prevalence of hepatic steatosis in CHB patients is 14% and is increasing year by year. In recent years, the prevalence of NAFLD has been increasing year by year, resulting in a significant increase in the number of patients with CHB combined with fatty liver. The severity of hepatic steatosis in patients with chronic viral hepatitis is positively correlated with the degree of liver fibrosis, and the risk factors for hepatic steatosis may also increase the incidence of cirrhosis and hepatocellular carcinoma in patients with CHC.