Background: Current evidence suggest that obesity and metabolic unhealthy status may be linked to a higher risk of several cancers. This study investigated whether thyroid cancer risk is increased by metabolic syndrome (MetS) and obesity phenotypes.

Methods: A total of 23151947 adults who participated in health screening between 2009-2014 were enrolled from the Korean National Health Insurance Database. Body mass index (BMI), waist circumference, fasting glucose, lipid profiles, and blood pressure were measured. Obesity status was subdivided into being metabolically healthy or unhealthy according to MetS besides BMI. Cox proportional hazards models were used to estimate the risk of thyroid cancer.

Results: During the average 5.6-years of follow-up, 158788 cases of thyroid cancer were newly identified. In multivariate models adjusted for age, smoking, drinking, exercise, and income status, the risk of thyroid cancer was increased with increasing BMI and presence of any MetS components. MetS was associated with 1.30-fold higher risk for thyroid cancer in men and 1.12-fold in women. Compared to metabolically healthy non-obese subjects, metabolically unhealthy non-obese subjects had a higher risk of thyroid cancer in both genders. However, metabolically unhealthy obesity versus metabolically healthy obesity were at greater risk for thyroid cancer only in men.

Conclusions: Components of Mets, especially obesity, and MetS were significantly associated with increased risk of thyroid cancer in Korean men and women. Moreover, metabolically unhealthy subjects were at higher risk of thyroid cancer despite normal BMI. Management of metabolic disorders may give additional benefit of thyroid cancer prevention.


E. Kim: None. K. Han: None. H. Kwon: None.

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