Metabolic syndrome and nonalcoholic fatty liver disease in a Spanish population: influence of the diagnostic criteria used

Abstract

Objective: Nonalcoholic fatty liver disease (NAFLD) is highly prevalent and it is considered the hepatic component of the metabolic syndrome (MetS). The WHO, the National Cholesterol Education Program (NCEP) and the International Diabetes Federation (IDF) have different criteria to define MetS. The aim of this study was to analyze the association between NAFLD and MetS using the three existing criteria.

Methods: Cross-sectional, descriptive population-based study derived from a previous study on the prevalence and factors associated with NAFLD in Spain.

Results: A total of 696 individuals [mean age 53 ± 14 years (range 17-83 years)] were included, 59% of whom were women. The prevalence of MetS was 34.2% according to the IDF, 17.7% according to the NCEP and 15.5% according to the WHO. Concordance among the different criteria was between 76 and 87%, with kappa indexes between 0.39 and 0.54. NAFLD was present in 184 individuals according to echographic criteria (prevalence 26.4%). The prevalence of NAFLD among patients with MetS was 43% (IDF), 53% (NCEP) and 64% (WHO). The odds ratio (95% confidence interval) for a logistic regression using NAFLD as a dependent variable varied from 3.44 (2.42-4.88) for IDF to 7.28 (4.68-11.3) for WHO, being 4.28 (2.84-6.43) for NCEP.

Conclusion: The MetS is quite frequent in the general population, although its prevalence varies considerably according to the criteria used for its definition. The MetS is associated with NAFLD, with the WHO definition being the best to determine its presence, probably because of the inclusion of insulin resistance as a main component. Unification of criteria is needed to adequately compare the prevalence of MetS and its relationship with NAFLD in different population groups.