Normal range of alanine aminotransferase concentration is associated with carotid atherosclerosis

ObjectiveTo investigate whether alanine aminotransferase (ALT), even within the reference range, is associated with atherosclerotic burden in apparently healthy adults.MethodsThis was an observational study performed on 830 healthy individuals with normal ALT concentration (≤40 U/L). Atherosclerotic burden was assessed by carotid arterial intima-media thickness (IMT). All subjects were divided according to the quartile based on their ALT concentrations.ResultsDespite all subjects having a normal ALT concentration, ultrasonographic liver steatosis was observed in 48.4% and 36.7% of men and women, respectively. In both genders, subjects in the highest quartile of ALT concentration had a significantly higher waist circumference, triglyceride concentration, HOMA-IR, a higher prevalence of metabolic syndrome, and a greater severity of ultrasonographic liver steatosis than did those in the lower quartiles. In women, the carotid IMT increased significantly with increasing quartiles of ALT concentration (0.62 ± 0.14 mm, 0.66 ± 0.15 mm, 0.69 ± 0.15 mm, vs. 0.72 ± 0.24 mm; P for trend < 0.001). Based on multivariate regression analysis, the serum ALT, even within the normal range, was associated with the carotid IMT in both men and women, and independently of traditional cardiovascular risk factors.ConclusionsALT concentrations, albeit within the reference range, were associated with atherosclerotic burden in healthy adults.