Thyroid Function and All-cause Mortality in the Context of Multimorbidity: Results From 2 Population-based Studies

We show an association between higher free T4 and mortality for individuals with multimorbidity, whereas lower free T3 was associated with poor survival in individuals with multimorbidity. Our results extend findings from patient populations to people with multimorbidity from the general population. Future research is needed to investigate whether these findings extend to levothyroxine users.