Korea: Patients with thyroid cancer who underwent thyroidectomy are at increased risk of developing type 2 diabetes mellitus than the matched controls, finds a recent study published in the Journal of Clinical Endocrinology & Metabolism. The researchers found a U-shaped dose-dependent association between levothyroxine dosage and the risk of type 2 diabetes.
Abnormal thyroid function following thyroidectomy and subsequent suppression of thyroid-stimulating hormone can have harmful effects on glucose homeostasis in patients with thyroid cancer. Hye Jin Yoo, Korea University College of Medicine, Seoul, Korea, and colleagues aimed to investigate whether thyroidectomy increases the risk of type 2 diabetes in thyroid cancer patients and to explore the association between levothyroxine dosage and type 2 diabetes risk.
For this purpose, they designed a retrospective population-based cohort study that included 36,377 thyroid cancer patients without known diabetes who underwent thyroidectomy between 2004 and 2013. Using 1:1 propensity score matching, the researchers selected matched non-thyroid cancer subjects.
The main outcome was newly developed type 2 diabetes mellitus.
The study revealed the following findings:
Thyroid cancer patients who underwent thyroidectomy had a higher risk of developing type 2 diabetes mellitus than the matched controls (hazard ratio [HR]: 1.43).
Among thyroid cancer patients, when the second quartile group (in terms of the mean levothyroxine dosage; 101–127 μg/day) was considered the reference group, the risk of type 2 diabetes mellitus increased in the first quartile (<101 μg/day; HR: 1.45) and fourth quartile groups (≥150 μg/day; HR: 1.37); meanwhile, the risk decreased in the third quartile group (128–149 μg/day; HR: 0.91).
"Thyroid cancer patients who underwent thyroidectomy were more likely to develop type 2 diabetes mellitus than the matched controls," the researchers wrote. "There was a U-shaped dose-dependent relationship between the levothyroxine dosage and type 2 diabetes mellitus risk."
Reference:
Eun Roh, Eunjin Noh, Soon Young Hwang, Jung A Kim, Eyun Song, Minjeong Park, Kyung Mook Choi, Sei Hyun Baik, Geum Joon Cho, Hye Jin Yoo, Increased risk of type 2 diabetes in patients with thyroid cancer after thyroidectomy: A nationwide cohort study, The Journal of Clinical Endocrinology & Metabolism, 2021;, dgab776, https://doi.org/10.1210/clinem/dgab776