Long-term metabolic risks after thyroidectomy and thyroid hormone therapy in thyroid cancer survivors: a nationwide cohort study

Abstract

Background As long-term survival rates improve among thyroid cancer patients, the metabolic consequences of thyroidectomy and thyroid hormone therapy have gained increasing importance. While these treatments are crucial for cancer management, their long-term effects on metabolic health remain inadequately understood. Methods We conducted a retrospective, population-based cohort study utilizing nationwide data from the Korea National Health Insurance Service. We estimated the risk of incident metabolic abnormalities (i) among patients with TC who underwent thyroidectomy compared with matched individuals from the general population without TC, (ii) among TC patients according to thyroidectomy status, and (iii) among TC patients who underwent thyroidectomy, according to thyroid hormone therapy status. The incidence of obesity, diabetes mellitus, hypertension, dyslipidemia, metabolic syndrome, and metabolic dysfunction-associated steatotic liver disease (MASLD) within 5, 8, and 10 years was estimated using multivariable logistic regression models, adjusting for age, sex, household income, alcohol consumption, smoking status, and physical activity. Results Thyroidectomy was associated with higher odds of multiple metabolic abnormalities compared with the matched general population without TC and to TC patients without thyroidectomy, with most associations evident from 5 years onward and some from 8 years. Among TC patients who underwent thyroidectomy, thyroid hormone therapy was significantly associated with metabolic abnormalities. In sex-stratified analyses, overall patterns were largely similar; however, MASLD was not significantly associated with thyroidectomy or thyroid hormone therapy in males. Conclusion Thyroidectomy and thyroid hormone therapy are associated with incidence of metabolic abnormalities within 5, 8, or 10 years among thyroid cancer survivors. These findings support ongoing metabolic monitoring in thyroid cancer survivors and warrant further studies to determine whether individualized hormone management can reduce long-term metabolic risk.