Prevalence and factors associated with the presence of nonalcoholic fatty liver disease in an adult population in Spain

Background/aims The prevalence of nonalcoholic fatty liver disease (NAFLD) is unknown in Spain. The purpose of detecting NAFLD patients is to determine the associated factors and prevent its evolution to more severe forms. The aim of this study is to determine the prevalence and factors associated with NAFLD. Methods This is a multicentre, cross-sectional, populational study. Individuals between 15 and 85 years of age were randomly selected from 25 primary healthcare centres in the province of Barcelona, Spain. Clinical histories were reviewed, and anamnesis, physical examination, blood analysis and hepatic echography were performed. Individuals with an alcohol intake greater than 30 g/day in men and greater than 20 g/day in women or with known liver disease were excluded. Results Seven hundred and sixty-six individuals with a mean age of 53±14 years (range 17–83, 42.2% men) were included in the study. One hundred and ninety-eight individuals presented NAFLD with echographic criteria (prevalence 25.8, 33.4% men and 20.3% women P<0.001). On multivariate analysis, the following were associated with NAFLD: male sex [odds ratio (OR): 2.34, 95% confidence interval (95% CI): 1.57–3.49], age (OR: 1.04 per year, 95% CI: 1.02–1.05), metabolic syndrome (OR: 2.19, 95% CI: 1.29–3.72), insulin resistance (OR: 6.00, 95% CI: 3.43–10.5) and alanine aminotransferase (OR: 4.21, 95% CI: 2.23–7.95). Of the individuals who consumed alcohol, 29.4% consumed alcohol within the inclusion criteria, with a mean of 9.17±6.75 standard beverage units per week. Moderate alcohol intake was not related to NAFLD, although a possible protector effect was found with the quantity consumed among the drinkers who did not consume excessive amounts of alcohol (OR: 0.93 per standard beverage units, 95% CI: 0.88–0.98). Conclusion NAFLD prevalence in our population is very high. Male sex, age, metabolic syndrome, insulin resistance and alanine aminotransferase are the factors associated with NAFLD. Furthermore, studies should be carried out with respect to the controversial effect of alcohol on NAFLD.