Prevalence and risk factors of nonalcoholic fatty liver disease in a general population, the HUNT study

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide and the metabolic syndrome is the main risk factor. Alanine aminotransferase (ALT) is widely used to screen for NAFLD, and the aims of this study were to assess the prevalence and risk factors of NAFLD in a general population.

The study was based on the third population-based Trøndelag Health Study (HUNT3), Norway, performed 2006-2008. In HUNT3, ALT and lipids were analyzed, anthropometric measures done, and comorbidity and risk factors reported. Elevated ALT was used to define NAFLD and participants with other diagnosed liver diseases and excessive alcohol consumption were excluded. Multivariable logistic regression reporting odds ratio (OR) and 95% confidence interval (CI) was used to assess risk factors.

In HUNT3, 2373 (4.7%) of 50,006 participants were diagnosed with NAFLD. The risk increased with obesity (OR 1.73, 95% CI 1.46-2.05) and very increased waist circumference (OR 1.97, 95% CI 1.65-2.35), and the risk increased dose-dependently (p for trend <0.001). Hypertension (OR 1.58, 95% CI 1.42-1.76), diabetes mellitus (OR 1.48, 95% CI 1.30-1.68), high triglycerides (OR 1.55, 95% CI 1.41-1.71), high total cholesterol (OR 1.52, 95% CI 1.29-1.81) and low high-density lipoproteins (OR 1.33, 95% CI 1.21-1.47) also increased the risk of NAFLD. The risk was lower in men (OR 0.71, 95% CI 0.64-0.79) and among current smokers (OR 0.79, 95% CI 0.70-0.89).

NAFLD is a common condition in the general population. NAFLD should be suspected in individuals with abdominal obesity, hypertension, diabetes mellitus and dyslipidemias.