THRB and diabetes mellitus: This discrepancy may reflect differences in: (i) outcome definitions (prediabetes vs. diabetes), as compensatory FT4 elevation in early metabolic dysfunction may transiently improve insulin sensitivity via TRβ-mediated mitochondrial uncoupling (33); and (ii) population characteristics (e.g., our cohort’s younger age [46.4 ± 13.7 years] vs. Laclaustra’s [55.7 ± 8.7 years]).