What is Nonalcoholic Fatty Liver Disease (NAFLD)?

From the Guidelines

Nonalcoholic Fatty Liver Disease (NAFLD) is a condition characterized by excess fat accumulation in the liver of people who drink little to no alcohol, affecting approximately 25% of the global population and existing on a spectrum ranging from simple fatty liver (steatosis) to nonalcoholic steatohepatitis (NASH), which can progress to fibrosis, cirrhosis, and even liver cancer. The primary cause of NAFLD is metabolic dysfunction, often associated with obesity, type 2 diabetes, high cholesterol, and metabolic syndrome, as stated in the study by 1. Most patients with NAFLD have no symptoms in early stages, though some may experience fatigue or discomfort in the upper right abdomen.

Key Characteristics of NAFLD

• Defined by the presence of steatosis in >5% of hepatocytes according to histological analysis or by a proton density fat fraction >5.6% assessed by proton magnetic resonance spectroscopy (1 H-MRS) or quantitative fat/water selective magnetic resonance imaging (MRI) 1
• Includes two pathologically distinct conditions with different prognoses: non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH)
• NASH covers a wide spectrum of disease severity, including fibrosis, cirrhosis, and hepatocellular carcinoma (HCC)

Diagnosis and Treatment

Diagnosis typically involves:

• Blood tests to assess liver function
• Imaging studies like ultrasound or MRI
• Sometimes liver biopsy for definitive assessment Treatment focuses on lifestyle modifications including:
• Weight loss through diet and exercise, which can reduce liver fat and inflammation
• Management of associated conditions like diabetes and high cholesterol Currently, no medications are specifically approved for NAFLD, though vitamin E (800 IU daily) may benefit non-diabetic patients with biopsy-proven NASH, as suggested by 1. Without intervention, approximately 20% of patients with NASH will progress to cirrhosis, making early detection and lifestyle changes crucial for preventing serious liver complications, as highlighted in the study by 1.

From the Research

Definition of Nonalcoholic Fatty Liver Disease (NAFLD)

• Nonalcoholic fatty liver disease (NAFLD) is a disorder characterized by excess accumulation of fat in hepatocytes [(2,3,4,5,6)].
• The main characteristic of NAFLD is the accumulation of excessive fat in hepatocytes without excess alcohol intake or other pathological causes 2.
• NAFLD is a progressive disease, ranging from steatosis to non-alcoholic steatohepatitis (NASH), cirrhosis, hepatocellular carcinoma, liver transplantation, and death [(2,3,4)].

Prevalence and Association of NAFLD

• NAFLD is the most prevalent chronic liver disease, affecting approximately one-quarter of the global adult population 2.
• It is closely associated with insulin resistance, obesity, dyslipidaemia, type 2 diabetes mellitus (T2DM), and cardiovascular disease [(3,4,5)].
• The prevalence of NAFLD is estimated to be 10-40% in adults worldwide, and it is the most common liver disease in children and adolescents in developed countries 4.

Diagnosis and Treatment of NAFLD

• Liver biopsy is currently considered the gold standard for the diagnosis and staging of NAFLD [(2,3,4)].
• There is no specific pharmacological therapy approved for NAFLD, although several drugs are in advanced stages of development [(2,3,6)].
• Lifestyle modifications, such as dietary changes and exercise, are essential for managing NAFLD [(3,5,6)].
• Novel antihyperglycemic agents, anti-hyperlipidemic drugs, and nutritional interventions have shown promise in improving insulin resistance and reducing inflammation [(5,6)].