Although the cause of NASH is unclear, the condition is associated with many risk factors. The three most important ones are closely related to metabolic syndrome and insulin resistance:
 Overweight and obesity. Your risk increases with every pound of excess weight. More than 70 percent of people with nonalcoholic steatohepatitis (NASH) are obese. Overweight is defined as having a body mass index between 25 and 29.9; obesity is defined as having a body mass index of 30 or higher.
 Diabetes. When your body becomes resistant to the effects of insulin or your pancreas doesn't produce enough insulin to maintain a normal blood sugar (glucose) level, this can damage many organs in your body, including your liver. As many as three in four people with NASH also have diabetes.
 Hyperlipidemia. High cholesterol levels and elevated triglycerides are common in people who develop NASH. It's estimated that up to 80 percent of people with NASH have hyperlipidemia.

Other risk factors include:
 Abdominal surgery. Operations to remove large sections of the small intestine (small bowel resection), treat obesity (gastric bypass) or bypass parts of the small intestine (jejunal bypass) often lead to rapid weight loss, which may increase your risk of nonalcoholic fatty liver disease.
 Medications. These include oral corticosteroids (prednisone, hydrocortisone, others), synthetic estrogens (Premarin, Ortho-Est, others) for menopause, amiodarone (Cordarone, Pacerone) for heart arrhythmias, tamoxifen for breast cancer and methotrexate Rheumatrex, Trexall), an immune-suppressing medication for rheumatoid arthritis.
 Other conditions. These include Wilson's disease, a hereditary condition that affects copper levels; Weber-Christian disease, which affects nutrient absorption; and abetalipoproteinemia, a rare congenital disorder that affects the ability to digest fat. Inherited metabolic disorders that increase the risk of cirrhosis include galactosemia, a rare disorder that affects the way the body metabolizes milk sugar (lactose), and glycogen storage diseases, which prevent glycogen, the stored form of glucose, from being formed or released when your body requires it.