Increased risk of nonalcoholic fatty liver disease in patients with thyroid cancer: a nationwide cohort study

Background Given that patients with thyroid cancer experience several metabolic disorders, it is inferred that these patients have an elevated risk of non-alcoholic fatty liver disease (NAFLD). However, large-scale studies on this topic are lacking. This study aimed to elucidate the association between thyroid cancer and NAFLD. Methods We used data from the Korean National Health Insurance Service Sample Cohort. A total of 1,407 patients with thyroid cancer and 4,221 matched controls were included following the exclusion process and propensity score matching at a ratio of 1:3. We analyzed hazard ratio, risk factors for NAFLD. Results The study revealed an increased risk of NAFLD (HR 2.28; 95% CI 1.69-3.10; P < 0.001) in patients with thyroid cancer. Thyroid cancer patients exhibited a higher risk of NAFLD when they had no regular exercise (HR 2.41; 95% CI 1.75-3.32). Moreover, body mass index (BMI) and levothyroxine dosage have been identified as potential critical factors for the development of NAFLD in patients with thyroid cancer. Conclusion The incidence rate of NAFLD was higher in patients with thyroid cancer than in the controls. Healthcare professionals should consider regular physical activity, BMI, and cumulative levothyroxine dosage when managing patients with thyroid cancer to mitigate the incidence of NAFLD.