What causes Nonalcoholic Steatohepatitis ?
Although NASH has become more common, its underlying cause is still not clear. It most often occurs in persons who are middle-aged and overweight or obese. Many patients with NASH have elevated blood lipids, such as cholesterol and triglycerides, and many have diabetes or prediabetes, but not every obese person or every patient with diabetes has NASH. Furthermore, some patients with NASH are not obese, do not have diabetes, and have normal blood cholesterol and lipids. NASH can occur without any apparent risk factor and can even occur in children. Thus, NASH is not simply obesity that affects the liver.
                
While the underlying reason for the liver injury that causes NASH is not known, several factors are possible candidates:
                
- insulin resistance  - release of toxic inflammatory proteins by fat cells (cytokines)  - oxidative stress (deterioration of cells) inside liver cells