In recent years, non-alcoholic fatty liver disease (fatty liver for short) in children has become more and more common and has become the most important chronic liver disease affecting children’s health after viral hepatitis. Despite different economic conditions and living habits, the prevalence of fatty liver disease in children is around 5%-7% across the country, and there is an increasing trend year by year; in Shanghai, for example, the prevalence of fatty liver disease in students aged 6-14 years in Shanghai was only 2.1% in 2008, but rose to 6.5% and 8.9% in 2011 and 2014, respectively, and surveys of a school in the city in 2001 and 2009 483 and 459 high school students in 2001 and 2009 also found that the prevalence of fatty liver increased from 4.8% to 7.0%. In obese children, the prevalence of fatty liver can reach 60%-70% or even 80%, and Japan reported that the prevalence of fatty liver in a group of 310 obese children was as high as 83%, of which 24% had liver function abnormalities marked by elevated transaminases (ALT). Although most children have a simple fatty liver with normal liver function, some foreign scholars reported that the results of histological examination of the liver of 100 children aged 2-18 years with clinical fatty liver showed that only 16% of them had simple hepatic fatty infiltration, while the remaining 84% had varying degrees of inflammation and/or fibrosis, and even simple fatty liver can progress to steatohepatitis if not controlled in time. Even simple fatty liver, if not controlled in time, can also progress to steatohepatitis and then to cirrhosis, eventually developing the same serious complications as other causes of cirrhosis, and even requiring liver transplantation. An American scholar followed 66 children with fatty liver with an average age of 13 years for up to 20 years, and 5 cases had 1-2 liver biopsies within 3-5 years, which revealed significant progression of liver fibrosis in 4 children, 2 of whom progressed from no fibrosis to fibrosis grade 3 (near cirrhosis) and cirrhosis, respectively, and 2 girls aged 11 and 18 years 9 and 7 years after the diagnosis of fatty liver due to Liver transplantation was performed for cirrhotic liver failure, the latter eventually dying at the age of 27 years due to recurrence of fatty liver-related cirrhosis and concomitant multi-organ failure. This confirms that children with fatty liver can also progress to irreversible end-stage liver disease, which may take as short as 10-20 years rather than the 30 years or longer previously thought. Moreover, most children with fatty liver can be asymptomatic, but in some patients the pathological damage to the liver persists and progresses quietly, becoming an important cause of occult cirrhosis in adulthood. Concomitant with metabolic diseases As in adults, fatty liver in children is often associated with metabolic diseases such as hyperlipidemia, hypertension and hyperglycemia. Compared with non-fatty liver children of the same age, children with fatty liver have a 50% decrease in insulin sensitivity index and a 3-fold increase in insulin resistance index, and nearly 10% of children with fatty liver have diabetes mellitus, impaired glucose tolerance and other glucose metabolism disorders, which is significantly higher than that of children in general. Similarly, the incidence of cardiovascular disease in children with fatty liver can be significantly higher than in normal healthy children. Scholars in Zhejiang, China, found that the incidence of hypertension in 110 children with fatty liver and 30 healthy children of the same age were 39.7% and 4.2%, respectively, a difference of nearly 10 times; scholars in the United States reported that the incidence of atherosclerosis (peripheral artery, coronary plaque formation or stenosis) in 123 children with fatty liver aged 2-19 years and 684 non-fatty liver children of the same age were 30% and 19%, respectively, while the incidence of atherosclerosis (peripheral artery, coronary plaque formation or stenosis) in Pathological examination of more than 800 children who died unexpectedly also confirmed that the incidence of atherosclerosis was 2 times higher in children with fatty liver than in children without fatty liver. These data suggest that children with fatty liver are not only at high risk for cardiovascular disease, but that fatty liver may be an early marker of cardiovascular disease. More alarmingly, of the 66 children with fatty liver in the United States, a surprising 2 children died of severe cardiovascular disease during follow-up, again providing clinical evidence that children with fatty liver die prematurely from cardiovascular disease rather than liver disease. It is well documented that fatty liver in children is not only a potentially progressive disease in itself, but can also be complicated by many serious diseases at the same time or in adulthood, especially diabetes mellitus and its complications as well as cardiovascular diseases, which seriously threaten their current and adult health and even life, and become an important reason for their shortened life expectancy. Early prevention and treatment to avoid malignant outcome Some foreign scholars call for: fatty liver in children is like a ticking time bomb, which must be paid great attention to early prevention and treatment to stop and avoid the progression of fatty liver to malignant outcome as much as possible. Unless it progresses to an advanced stage, fatty liver is generally preventable and treatable. Therefore, the U.S. Guidelines for the Prevention and Treatment of NAFLD specifically recommend that strong lifestyle changes should be the first line of treatment for children with fatty liver, and that diet control and increased exercise are the most important and effective measures to prevent and treat fatty liver, even when medication is needed for steatohepatitis or even fatty liver-related cirrhosis. It should also be done on the basis of lifestyle correction, otherwise it will be half the effort. However, children are at a special stage of physical and mental development and have special requirements for lifestyle modification. First, on the basis of the principle of total calorie control and appropriate reduction of high-fat and high-sugar foods, more emphasis should be placed on a balanced diet to avoid shifting from one extreme of excessive nutrition to another extreme of nutritional deficiency, so as to fully ensure the intake of nutrients required for the growth and development of children and adolescents. Second, prevention and treatment of fatty liver in children should be early. There are reports of fatty liver in children aged 5-6 years old in China and 2 years old in foreign countries, and fatty liver cirrhosis in children aged 8 years old, and a survey of 178 17-year-old children with fatty liver and 800 non-fatty liver children of the same age in Australia found that the occurrence of fatty liver in adolescents is closely related to obesity at the age of 3-4 years old, so it is not a good thing to be “big afro”. The prevention and treatment of fatty liver in children should be started from children. Third, most children are not capable of independent living, especially self-control. Therefore, parents and school teachers have more responsibility to guide, direct, supervise and manage the prevention and treatment of fatty liver in children, and only with the joint attention of families, schools and even the whole society can the trend of increasing incidence of fatty liver in children be curbed and the harm of fatty liver to children be minimized.