Prevalence of primary non-alcoholic fatty liver disease in a population-based study and its association with biochemical and anthropometric measures.

BACKGROUND/AIMS: Only a few studies have assessed the epidemiology of non-alcoholic fatty liver disease (NAFLD). The aim was to evaluate the prevalence of primary NAFLD in a population-based study in Israel and to determine independent risk factors. METHODS: A cross-sectional study of a subsample of the Israeli national health survey (n=352). Individuals with a known etiology for secondary NAFLD were excluded. Each participant underwent an abdominal ultrasound, biochemical tests and an anthropometric evaluation. RESULTS: Three hundred and twenty-six subjects (53.4% male, mean age 50.5+/-10.3 standard deviaton SD]) met the inclusion criteria. The prevalence of primary NAFLD was 30% (25-35% 95% confidence intervals CI]). NAFLD was more prevalent in men than women (38% vs. 21%; P=0.001). Compared with ultrasonography, the sensitivity of serum alanine transaminase (ALT) for the diagnosis of primary NAFLD was 8.2%. Risk factors independently associated with NAFLD included male gender (odds ratios (OR)=2.8, 95% CI 1.5-5.3), abdominal obesity (OR=2.9, 95% CI 1.3-6.4), homeostasis model assessment (OR=5.8, 95% CI 2.0-17.2), hyperinsulinemia (OR=2.3, 95% CI 1.2-4.3, P=0.01) and hypertriglyceridemia (OR=2.4, 95% CI 1.3-4.5). CONCLUSIONS: NAFLD is prevalent in the general Israeli population and closely related to the metabolic syndrome. The use of ALT as a marker for NAFLD seriously underestimates its prevalence.