Incidence of non-alcoholic fatty liver disease in Hong Kong: a population study with paired proton-magnetic resonance spectroscopy

Background & aims: Because abdominal ultrasonography cannot reliably quantify hepatic steatosis, accurate data on the incidence of non-alcoholic fatty liver disease (NAFLD) are lacking. We aimed to study the population incidence of NAFLD with state-of-the-art non-invasive tests.

Methods: This was a prospective cohort study. The intrahepatic triglyceride (IHTG) content was measured serially with proton-magnetic resonance spectroscopy in community subjects. Transient elastography was performed to assess liver fibrosis.

Results: 565 subjects (mean age 48 years, 62.7% women) without NAFLD at baseline underwent follow-up assessment after a median interval of 47 months (range 34-60 months). 78 (13.8%) subjects developed incident fatty liver with a mean IHTG content of 8.9% (SD 5.3%). 16 (20.5%) subjects had an IHTG content ⩾ 11.0% suggestive of moderate to severe steatosis. After excluding 2 men with significant alcohol consumption, the population incidence of NAFLD at 3-5 years was 13.5% (95% CI 10.6-16.3%; 3.4% per year). Only 1 subject with incident NAFLD had high liver stiffness (11.1 kPa) suggestive of advanced fibrosis. Metabolic syndrome at baseline was the strongest predictor of incident fatty liver. Incident central obesity developed in 31.0% of subjects with incident fatty liver and 5.6% of those without (p<0.001). No subject with incident fatty liver had regression of impaired fasting glucose, which occurred in 51.1% of those without incident fatty liver (p=0.001).

Conclusions: 13.5% of the Hong Kong Chinese adult population develop NAFLD in 3-5 years, but few have severe steatosis or advanced fibrosis. Metabolic syndrome is the most important risk factor of incident NAFLD.