Prevalence and severity of nonalcoholic fatty liver disease by transient elastography: Genetic and metabolic risk factors in a general population.

BACKGROUND & AIMS: The worldwide spread of obesity is leading to a dramatic increase in the prevalence of nonalcoholic fatty liver disease (NAFLD) and its complications. We aimed to evaluate both prevalence and factors associated with NAFLD in a general population in a Mediterranean area.

METHODS: We considered 890 consecutive individuals included in the community-based ABCD (Alimentazione, Benessere Cardiovascolare e Diabete) study (ISRCTN15840340). Controlled attenuation parameter (CAP) and liver stiffness measurement (LSM) were measured with FibroScan. Participants were genotyped for PNPLA3 rs738409 and TM6SF2 rs58542926 variants.

RESULTS: The prevalence of NAFLD in the cohort was 48%. NAFLD participants exhibited elevated LSM values, suggesting advanced fibrosis (6.5% of cases). Both NAFLD and advanced fibrosis were independently associated with traditional risk factors (NAFLD: age >50 years, obesity, hypertension, elevated ALT and low HDL-cholesterol serum concentrations. Advanced fibrosis: IFG/diabetes, elevated ALT serum concentrations). A high prevalence (>60%) of NAFLD was found in obese people, while it varied widely in non-obese people according to the presence of metabolic risk factors. PNPLA3 G variant (OR = 1.33, 95% C.I. = 1.01-1.8; P < .05) was independently associated with NAFLD. Prevalence of advanced fibrosis (high LSM values) ranged from 3.4% (no risk factors) to 60% (presence of all risk factors). TM6SF2 T variant (OR = 3.06, 95% C.I. = 1.08-8.65, P < .05) was independently associated with advanced fibrosis (high LSM values).

CONCLUSIONS: In a cohort of a general population, the prevalence of NAFLD was very high, and among NAFLD patients a significant proportion had advanced fibrosis (high LSM values). Apart from traditional risk factors, genetic factors may have a significant role that needs to be further investigated.