Non-Alcoholic Fatty Liver Disease (NAFLD)
Excess fat accumulation in the liver unrelated to alcohol. The most common chronic liver disease worldwide and the leading cause of mildly elevated liver enzymes.
What it is
NAFLD is fat infiltration of >5% of hepatocytes without significant alcohol intake (men <30 g/day, women <20 g/day) or other causes (viral hepatitis, drugs, autoimmune). It exists on a spectrum: simple steatosis (just fat) progresses in a minority to non-alcoholic steatohepatitis (NASH, fat plus inflammation and hepatocyte injury), then to fibrosis, cirrhosis, and a small minority to hepatocellular carcinoma. Globally, ~25% of adults have NAFLD; the prevalence is climbing alongside obesity and type 2 diabetes. The renamed terminology MAFLD/MASLD (metabolic dysfunction-associated) emphasises the central role of metabolic syndrome.
Key lab markers
- ALT — most commonly elevated; AST often modestly elevated too. AST/ALT ratio <1 typically (in contrast to alcoholic liver disease).
- GGT — frequently elevated.
- Triglycerides, HDL — usually deranged in the metabolic-syndrome pattern.
- HbA1c, fasting glucose — link to type 2 diabetes risk.
- FIB-4 score (calculated from age, AST, ALT, platelets) — screens for advanced fibrosis without imaging.
- Liver ultrasound — confirms steatosis; elastography assesses fibrosis non-invasively.
Symptoms
Most patients are asymptomatic — NAFLD is typically discovered through a routine ALT elevation or an incidental finding on ultrasound. Late-stage disease may cause:
- Right-upper-quadrant discomfort
- Fatigue
- Hepatomegaly
- Signs of portal hypertension or cirrhosis in advanced cases
When to discuss with a doctor
A persistent ALT elevation in someone with metabolic-syndrome features warrants a primary-care work-up: viral hepatitis serology, ultrasound, FIB-4 calculation. NAFLD with significant fibrosis (FIB-4 >2.67 or transient elastography >8 kPa) warrants hepatology referral. The cornerstone of treatment is 7–10% weight loss — this consistently reverses steatosis and improves fibrosis. No first-line drug therapy is currently approved for NAFLD itself, though GLP-1 agonists and resmetirom (recently approved) are increasingly used. Mediora.AI flags the ALT pattern in the context of HbA1c and lipids.