Triiodothyronine is associated with incidence and resolution of fatty liver disease: a longitudinal study in euthyroid Korean adults

Abstract

The positive relationship between triiodothyronine (T3) and fatty liver demonstrated only in cross-sectional study. In this longitudinal cohort study, we aimed to evaluated whether total T3 (TT3) is associated with the development/resolution of fatty liver. We included 1665 South Korean euthyroid adults with ≥ 4 thyroid function tests. We explored the impact of TT3 average on development/resolution of either fatty liver (diagnosed by ultrasound) or modified metabolic dysfunction-associated fatty liver (MAFLD) using Cox proportional hazards regression models. During median 5 years follow-up, 891 (66.9%) participants among participants without fatty liver at baseline developed fatty liver, and 265 (79.6%) participants among participants with fatty liver at baseline resolved fatty liver. Compared with low TT3 average group, high TT3 average group was positively associated with development of fatty liver [adjusted HR 1.17 (1.03–1.34); P = 0.016] and inversely associated with resolution of fatty liver [adjusted HR 0.64 (0.50–0.82); P < 0.001]. The statistical significance was remained for development [adjusted HR 1.24 (1.07–1.44); P = 0.004] and resolution [adjusted HR 0.72 (0.54–0.95); P = 0.024] of modified MAFLD. Our finding provides longitudinal evidence that TT3 level was associated with development and resolution of either fatty liver or modified MAFLD.