Prevalence and etiology of altered liver tests: a population-based survey in a Mediterranean town.

Serum biochemical liver tests (LTs) (ALT, AST, GGT) and platelet counts are often used to screen for chronic liver disease. Population-based data on abnormal LTs in Mediterranean areas are lacking. The prevalence and etiology of abnormal LTs were assessed from 2002 to 2003 in a 1 in 5 systematic random sample of the general population who were 12 years of age or older in Cittanova, a southern Italian town with 10,600 inhabitants. LTs, indices of metabolism, and markers of HBV and HCV infection were assayed and alcohol intake was recorded in the selected population. In virus-free individuals with abnormal LTs, LTs were retested, and upper abdominal echography and tests for other causes of liver damage were undertaken. Among the 1,645 individuals screened, the prevalence of anti-HCV was 6.5%; the prevalence was particularly high in individuals over 50 years of age. The corresponding prevalence for HBsAg was 0.8%. The overall prevalence of individuals with abnormal LTs was 12.7% (95% CI: 11.1-14.3). The probable cause of abnormal LTs was excessive alcohol in 45.6%, HCV in 18.6%, HBV in 1%, alcohol plus HCV and/or HBV in 8.8%, and rare diseases in 2%. In 24% of individuals with abnormal LTs, the probable cause was nonalcoholic fatty liver disease (NAFLD); in this subgroup, increased body weight, hypercholesterolemia, and hyperglycemia were common, and 63.3% of them had a bright liver at echography. In conclusion, in southern Italy, a Mediterranean area where dietary habits are different from those in industrialized areas, one eighth of the general population has abnormal LTs suggestive of possible liver damage; NAFLD appears to be emerging as a potentially important etiology of this presumed liver injury.