Objective: We examined whether metabolic syndrome (MetS) predicts increased alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGT) levels in young adults, whether spontaneous recovery from MetS has a favorable effect on liver enzyme activities, and whether these enzymes contribute to the atherogenicity of MetS (assessed by carotid intima-media thickness (IMT)).
Methods: The study included 1,553 subjects (base-line age 31.5 ± 5.0 years). ALT and GGT were measured in 2007. MetS was diagnosed by the new Joint Interim Societies definition.
Results: ALT and GGT levels were higher in subjects with MetS compared to those without in 2007. The association was independent of alcohol intake and BMI. In multivariable models adjusted for base-line age, LDL cholesterol, CRP, alcohol intake, and adiponectin, MetS in 2001 predicted increased ALT (β ± SEM = 0.320 ± 0.062, P < 0.0001 in men; 0.134 ± 0.059, P = 0.02 in women) and GGT (β ± SEM = 0.222 ± 0.067, P < 0.0001 in men; 0.236 ± 0.060, P < 0.0001 in women) levels after 6 years. Subjects with MetS only at base-line (2001) had lower ALT levels after 6 years compared to subjects with persistent and incident MetS. No statistically significant interaction for MetS*ALT (P = 0.81) or MetS*GGT (P = 0.92) on IMT was observed.
Conclusion: In young adults MetS may induce liver enzyme changes that indicate increased risk of non-alcoholic fatty liver disease, but we found no evidence that increased enzyme levels would amplify the atherogenicity of MetS.