Non-alcoholic fatty liver disease: a multicentre clinical study by the Italian Association for the Study of the Liver.

To define the characteristics of the Italian patient presenting non-alcoholic fatty liver disease. A total of 305 patients with abnormally high plasma aminotransferase and/or gamma-glutamyl-transpeptidase levels for at least 12 months, with no known cause of chronic liver damage, were consecutively enrolled in the study. Clinical, routine biochemical and liver histology investigations were carried out in all patients. Also evaluated were: (a) oral glucose load; (b) insulinaemia and insulin-resistance using the HOMA test model; and (c) plasma endotoxaemia, total antioxidant plasma capability, tumour necrosis factor-alpha, plasma interleukin-6 and -10 levels. Malondialdehyde and 4-hydroxynonenal content were determined on liver samples from 120 patients. The majority of patients were young overweight or obese males, with dyslipidaemia (20-60%), diabetes (10.5%), hyperinsulinaemia (40%), hyperferritinaemia (35%). Endotoxaemia was negative in all patients and cytokines were only sporadically altered. Total antioxidant plasma capability was decreased in 38.4% of the patients. Eighty percent of the cases had histological steatosis with a mild degree of inflammation and fibrosis. Seven patients had cirrhosis. Lipid peroxidation markers were increased in 90% of the cases, inversely correlated with fibrosis. Even if at univariate analysis, age, ferritin and tissue 4-hydroxynonenal were independent factors of steatosis (P < 0.01), and insulin, HOMA and ferritin of inflammation and fibrosis (P < 0.01), at multivariate analysis no single factor was found to be an independent predictor of hepatic lesions. The typical Italian patient with non-alcoholic fatty liver disease is a young male, obese, not diabetic, with a variable incidence of dyslipidaemia and hyperinsulinaemia. Only liver biopsy may define the type of liver damage.