NAFLD is considered to cover a spectrum of disease activity. This spectrum begins as fatty accumulation in the liver (hepatic steatosis). A liver can remain fatty without disturbing liver function, but by varying mechanisms and possible insults to the liver may also progress to become non-alcoholic steatohepatitis (NASH), a state in which steatosis is combined with inflammation and fibrosis (steatohepatitis). Based on initial diagnoses assigned in our study, the proportion of such diseases was very large: 24.1% for NAFLD and 18.1% for ALD (42.2% total). NAFLD was directly associated with obesity and metabolic syndrome. The prevalence of NAFLD was 27.0% (8,315/30,754), of which 80.3% had steatosis, 16.8% had steatohepatitis and 2.9% had disease at the cirrhotic stage. Most cases of NAFLD were observed in those aged 50-59 years (31.1%), 40-49 years (23.6%), and 60-69 years (18.1%).
The exact cause of NAFLD is still unknown. However, both obesity and insulin resistance probably play a strong role in the disease process. The exact reasons and mechanisms by which the disease progresses from one stage to the next are not known.The more severe form of NAFLD is called nonalcoholic steatohepatitis (NASH). NASH causes the liver to swell and may lead to liver scarring. NASH tends to develop in people who are overweight or obese, or have diabetes, high cholesterol or high triglycerides. However, some people have NASH even if they do not have any risk factors